Initial implementation of SwiftDBAI

Chat with any SQLite database using natural language. Built on
AnyLanguageModel (HuggingFace) for LLM-agnostic provider support
and GRDB for SQLite access.

Core features:
- Auto schema introspection from sqlite_master (zero config)
- NL → SQL generation via any AnyLanguageModel provider
- Three rendering modes: text summary, data table, Swift Charts
- Drop-in DataChatView (SwiftUI) and headless ChatEngine
- Operation allowlist with read-only default
- Mutation policy with per-table control
- ToolExecutionDelegate for destructive operation confirmation
- Multi-turn conversation context
- 352 tests across 24 suites, all passing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,7 @@
+.build/
+.swiftpm/
+Package.resolved
+*.xcodeproj/
+xcuserdata/
+DerivedData/
+.DS_Store

CLAUDE.md

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+<!-- ooo:START -->
+<!-- ooo:VERSION:0.14.0 -->
+# Ouroboros — Specification-First AI Development
+
+> Before telling AI what to build, define what should be built.
+> As Socrates asked 2,500 years ago — "What do you truly know?"
+> Ouroboros turns that question into an evolutionary AI workflow engine.
+
+Most AI coding fails at the input, not the output. Ouroboros fixes this by
+**exposing hidden assumptions before any code is written**.
+
+1. **Socratic Clarity** — Question until ambiguity ≤ 0.2
+2. **Ontological Precision** — Solve the root problem, not symptoms
+3. **Evolutionary Loops** — Each evaluation cycle feeds back into better specs
+
+```
+Interview → Seed → Execute → Evaluate
+    ↑                           ↓
+    └─── Evolutionary Loop ─────┘
+```
+
+## ooo Commands
+
+Each command loads its agent/MCP on-demand. Details in each skill file.
+
+| Command | Loads |
+|---------|-------|
+| `ooo` | — |
+| `ooo interview` | `ouroboros:socratic-interviewer` |
+| `ooo seed` | `ouroboros:seed-architect` |
+| `ooo run` | MCP required |
+| `ooo evolve` | MCP: `evolve_step` |
+| `ooo evaluate` | `ouroboros:evaluator` |
+| `ooo unstuck` | `ouroboros:{persona}` |
+| `ooo status` | MCP: `session_status` |
+| `ooo setup` | — |
+| `ooo help` | — |
+
+## Agents
+
+Loaded on-demand — not preloaded.
+
+**Core**: socratic-interviewer, ontologist, seed-architect, evaluator,
+wonder, reflect, advocate, contrarian, judge
+**Support**: hacker, simplifier, researcher, architect
+<!-- ooo:END -->

PRD.md

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+# SwiftDBAI — Product Requirements Document
+
+> **SwiftDBAI** is the umbrella name for AI-powered SQLite database tooling. v1 ships `SwiftDBAI` (chat + SQL engine). Future versions may add `SwiftDBAIMCP` (MCP server mode).
+
+**Version:** 0.2 (Revised — post-pivot from SwiftDataAI)
+**Date:** 2026-04-04
+**Author:** Krishna Kumar
+
+---
+
+## 1. Problem Statement
+
+Developers building apps with SQLite databases have no natural-language interface to query, explore, or mutate their data. Debugging, prototyping, and building AI-powered features all require hand-writing SQL — even for simple questions like "show me all overdue tasks" or "how many users signed up this week."
+
+There is no drop-in Swift package that lets a user (or an LLM) **chat with any SQLite database** using plain English.
+
+---
+
+## 2. Vision
+
+**SwiftDBAI** is a Swift package that gives any SQLite-backed app a conversational interface to its data. Developers embed it in minutes; end users ask questions and get answers from their own data.
+
+The data layer is **all SQL via GRDB** — no SwiftData APIs, no `#Predicate`, no `FetchDescriptor`. SwiftDBAI works with **any SQLite database**, not just SwiftData stores. Schema discovery is automatic via `sqlite_master` introspection — zero configuration required. The developer passes their own GRDB `DatabasePool` or `DatabaseQueue`; SwiftDBAI never manages the connection lifecycle.
+
+Built on [**AnyLanguageModel**](https://github.com/huggingface/AnyLanguageModel) from Hugging Face — a unified Swift LLM abstraction that supports OpenAI, Anthropic, Gemini, Ollama, CoreML, MLX, and llama.cpp through a single API. SwiftDBAI generates SQL from natural language, validates it against a developer-configured operation allowlist, executes it via GRDB, and renders results as text, data tables, or Swift Charts.
+
+---
+
+## 3. Target Users
+
+| Persona | Need |
+|---|---|
+| **iOS/macOS Developer** | Drop-in chat UI + engine to add "talk to your data" features to any SQLite-backed app without building NLP pipelines |
+| **AI/LLM App Builder** | SQL generation layer that lets an LLM read/write any SQLite database through validated, allowlisted operations |
+| **Power User / Debugger** | In-app console to inspect and mutate SQLite data during development |
+
+---
+
+## 4. Goals & Non-Goals
+
+### Goals
+- Natural-language querying of any SQLite database via GRDB
+- **LLM-agnostic** via [AnyLanguageModel](https://github.com/huggingface/AnyLanguageModel) — works with OpenAI, Anthropic, Gemini, Ollama, CoreML, MLX, llama.cpp out of the box
+- Drop-in SwiftUI chat view that "just works" with zero configuration — provide a database path and a model
+- Schema-aware — automatically introspects tables, columns, types, primary keys, foreign keys, and indexes from `sqlite_master`
+- Read **and** write support (SELECT, INSERT, UPDATE, DELETE) with developer-configured operation allowlist and confirmation guards
+- All SQL validation via allowlist check — no SQL parser for safety, no `#Predicate` generation
+- UI rendering: text summaries + scrollable data tables + Swift Charts (bar, line, pie) — all in v1
+- Swift 6 concurrency safe, structured concurrency throughout (Swift 6.1 language mode)
+- Works on iOS 17+, macOS 14+, visionOS 1+
+
+### Non-Goals (v1)
+- ~~Replacing Core Data~~ Not tied to any ORM — works with raw SQLite
+- Building a general-purpose chat framework (data-scoped only)
+- Full SQL parsing for safety (allowlist check is sufficient)
+- Training or fine-tuning models
+- Cloud sync of chat history
+- Managing database connections (developer owns the GRDB connection)
+
+---
+
+## 5. Architecture Overview
+
+```
+┌──────────────────────────────────────────────────────────┐
+│                       SwiftDBAI                          │
+├──────────┬───────────┬──────────────┬────────────────────┤
+│ Chat UI  │  Engine   │ Schema       │  SQL Pipeline      │
+│ (SwiftUI)│           │ Introspector │                    │
+└────┬─────┴─────┬─────┴──────┬───────┴───────┬────────────┘
+     │           │            │               │
+     ▼           ▼            ▼               ▼
+  ChatView   ChatEngine   sqlite_master    SQLQueryParser
+  DataChat   PromptBuilder  PRAGMA         OperationAllowlist
+  View       TextSummary    table_info     MutationPolicy
+             Renderer       foreign_keys   QueryValidator
+                            index_list
+┌──────────────────────────────────────────────────────────┐
+│            Rendering Layer                               │
+├──────────┬──────────────┬────────────────────────────────┤
+│  Text    │  DataTable   │  Swift Charts                  │
+│ Summary  │  (scrollable)│  (Bar, Line, Pie)              │
+└──────────┴──────────────┴────────────────────────────────┘
+┌──────────────────────────────────────────────────────────┐
+│                    GRDB.swift 7.0+                        │
+│              DatabasePool / DatabaseQueue                 │
+└──────────────────────────────────────────────────────────┘
+┌──────────────────────────────────────────────────────────┐
+│              AnyLanguageModel (HuggingFace)              │
+├──────┬──────┬────────┬───────┬───────┬──────┬────────────┤
+│OpenAI│Claude│ Gemini │Ollama │CoreML │ MLX  │ llama.cpp  │
+└──────┴──────┴────────┴───────┴───────┴──────┴────────────┘
+```
+
+### 5.1 Core Modules
+
+| Module | Responsibility |
+|---|---|
+| **SchemaIntrospector** | Queries `sqlite_master`, `PRAGMA table_info`, `PRAGMA foreign_key_list`, and `PRAGMA index_list` to auto-discover all tables, columns (name, type, nullability, defaults), primary keys, foreign keys, and indexes. Produces a `DatabaseSchema` model the LLM uses as context. Zero configuration — no annotations or model definitions needed. |
+| **SQLQueryParser** | Extracts SQL from the raw LLM response, detects the operation type (SELECT/INSERT/UPDATE/DELETE), validates it against the `OperationAllowlist`, enforces `MutationPolicy` table restrictions, and flags destructive operations that require confirmation. |
+| **OperationAllowlist** | Developer-configured set of permitted SQL operations. Presets: `.readOnly` (SELECT only, the default), `.standard` (SELECT + INSERT + UPDATE), `.unrestricted` (all including DELETE). |
+| **MutationPolicy** | Builds on `OperationAllowlist` with per-table restrictions. Controls which mutations are allowed on which tables. DELETE requires confirmation by default. |
+| **QueryValidator** | Extensible protocol for custom pre-execution validation rules (e.g., `TableAllowlistValidator`, `MaxRowLimitValidator`). Developers implement `QueryValidator` to add domain-specific checks. |
+| **ChatEngine** | Orchestrates the full pipeline: schema introspection (once, lazily) -> system prompt with schema context -> LLM generates SQL -> `SQLQueryParser` validates -> GRDB executes -> `TextSummaryRenderer` summarizes -> response. Supports multi-turn conversation with configurable context window. |
+| **PromptBuilder** | Constructs the LLM system prompt including the introspected schema description, allowlist rules, and optional developer-provided context. |
+| **TextSummaryRenderer** | Uses the LLM to generate natural-language summaries of query results. Configurable max rows for summarization. |
+| **ChatView / DataChatView** | Drop-in SwiftUI views. `DataChatView` is the zero-config entry point (database path + model). `ChatView` accepts a `ChatViewModel` for full control. Renders message bubbles, scrollable data tables, Swift Charts (bar/line/pie via `ChartDataDetector`), and error states. |
+
+### 5.2 Data Flow
+
+```
+User types: "Show me all tasks due this week"
+       │
+       ▼
+ChatEngine ensures schema is introspected (via SchemaIntrospector)
+  - Queries sqlite_master, PRAGMA table_info, foreign_key_list, index_list
+  - Caches DatabaseSchema for subsequent queries
+       │
+       ▼
+PromptBuilder constructs system prompt with:
+  - Full schema description (tables, columns, types, keys, indexes)
+  - OperationAllowlist rules
+  - Optional developer context
+  - Conversation history (within context window)
+       │
+       ▼
+LanguageModelSession.respond(to: userMessage)
+  → AnyLanguageModel routes to configured provider (OpenAI / Anthropic / Ollama / ...)
+       │
+       ▼
+LLM returns raw SQL: "SELECT * FROM tasks WHERE dueDate >= date('now', 'weekday 0', '-7 days') ORDER BY dueDate ASC"
+       │
+       ▼
+SQLQueryParser:
+  1. Extracts SQL from LLM response (strips markdown fences, etc.)
+  2. Detects operation type → SELECT
+  3. Validates against OperationAllowlist → allowed
+  4. Checks MutationPolicy table restrictions (if applicable)
+  5. Runs custom QueryValidators
+       │
+       ▼
+GRDB executes SQL via DatabasePool/DatabaseQueue
+  → Returns rows as [[String: Value]] with column names
+       │
+       ▼
+TextSummaryRenderer asks LLM to summarize results in natural language
+ChartDataDetector checks if results are chart-eligible
+       │
+       ▼
+ChatView renders: text summary + scrollable DataTable + Swift Charts (if applicable)
+```
+
+---
+
+## 6. Key APIs (Implemented)
+
+### 6.1 Setup (Minimal — Zero Config)
+
+```swift
+import SwiftDBAI
+import AnyLanguageModel
+
+struct ContentView: View {
+    var body: some View {
+        // Just a database path and a model — that's it
+        DataChatView(
+            databasePath: "/path/to/mydata.sqlite",
+            model: OllamaLanguageModel(model: "llama3")
+        )
+    }
+}
+```
+
+### 6.2 Choosing a Provider (via AnyLanguageModel)
+
+```swift
+import AnyLanguageModel
+
+// OpenAI
+let model = OpenAILanguageModel(apiKey: "sk-...", model: "gpt-4o")
+
+// Anthropic
+let model = AnthropicLanguageModel(apiKey: "sk-ant-...", model: "claude-sonnet-4-20250514")
+
+// Ollama (local)
+let model = OllamaLanguageModel(model: "llama3")
+
+// Gemini
+let model = GeminiLanguageModel(apiKey: "...", model: "gemini-2.0-flash")
+
+// Pass to DataChatView with options
+DataChatView(
+    databasePath: "/path/to/db.sqlite",
+    model: model,
+    allowlist: .standard,
+    additionalContext: "This database stores a recipe app's data."
+)
+```
+
+### 6.3 Bringing Your Own GRDB Connection
+
+```swift
+import GRDB
+import SwiftDBAI
+
+// Developer manages their own connection
+let dbPool = try DatabasePool(path: "/path/to/mydata.sqlite")
+
+// Option A: DataChatView with existing connection
+DataChatView(
+    database: dbPool,
+    model: model,
+    allowlist: .readOnly
+)
+
+// Option B: Headless / programmatic use via ChatEngine
+let engine = ChatEngine(
+    database: dbPool,
+    model: model,
+    allowlist: .standard
+)
+
+let response = try await engine.send("How many tasks are overdue?")
+print(response.summary)     // "You have 12 overdue tasks."
+print(response.sql)         // "SELECT COUNT(*) FROM tasks WHERE dueDate < date('now')"
+print(response.queryResult) // QueryResult with columns, rows, execution time
+```
+
+### 6.4 Schema Introspection (Auto — Zero Config)
+
+```swift
+// Schema is introspected automatically on first query.
+// Or pre-warm it explicitly:
+let schema = try await engine.prepareSchema()
+
+// schema.tableNames → ["tasks", "projects", "users"]
+// schema.tables["tasks"]?.columns → [ColumnSchema(name: "id", type: "INTEGER", isPrimaryKey: true), ...]
+// schema.tables["tasks"]?.foreignKeys → [ForeignKeySchema(fromColumn: "projectId", toTable: "projects", ...)]
+// schema.schemaDescription → Compact text for LLM prompts
+
+// No @Model annotations, no #Predicate, no FetchDescriptor.
+// Just sqlite_master + PRAGMA introspection.
+```
+
+### 6.5 Operation Allowlist (Safety)
+
+```swift
+// Presets
+let readOnly = OperationAllowlist.readOnly          // SELECT only (default)
+let standard = OperationAllowlist.standard          // SELECT + INSERT + UPDATE
+let unrestricted = OperationAllowlist.unrestricted  // All including DELETE
+
+// Custom
+let custom = OperationAllowlist([.select, .insert]) // Only SELECT and INSERT
+
+// Pass to ChatEngine or DataChatView
+let engine = ChatEngine(
+    database: dbPool,
+    model: model,
+    allowlist: .standard
+)
+```
+
+### 6.6 Mutation Policy (Table-Level Control)
+
+```swift
+// Read-only (default)
+let readOnly = MutationPolicy.readOnly
+
+// Allow INSERT and UPDATE on specific tables only
+let restricted = MutationPolicy(
+    allowedOperations: [.insert, .update],
+    allowedTables: ["orders", "order_items"]
+)
+
+// Full access — DELETE requires confirmation by default
+let full = MutationPolicy.unrestricted
+
+let engine = ChatEngine(
+    database: dbPool,
+    model: model,
+    mutationPolicy: restricted
+)
+```
+
+### 6.7 Custom Query Validators
+
+```swift
+// Built-in: restrict queries to specific tables
+let tableValidator = TableAllowlistValidator(
+    allowedTables: ["tasks", "projects"]
+)
+
+// Built-in: enforce row limits on SELECT queries
+let limitValidator = MaxRowLimitValidator(maxRows: 1000)
+
+// Custom: implement QueryValidator protocol
+struct NoJoinValidator: QueryValidator {
+    func validate(sql: String, operation: SQLOperation) throws {
+        if sql.uppercased().contains("JOIN") {
+            throw QueryValidationError.rejected("JOIN queries are not allowed.")
+        }
+    }
+}
+
+let config = ChatEngineConfiguration(
+    validators: [tableValidator, limitValidator, NoJoinValidator()]
+)
+
+let engine = ChatEngine(
+    database: dbPool,
+    model: model,
+    allowlist: .readOnly,
+    configuration: config
+)
+```
+
+### 6.8 Tool Execution Delegate (Destructive Operation Confirmation)
+
+```swift
+let engine = ChatEngine(
+    database: dbPool,
+    model: model,
+    allowlist: .unrestricted,
+    delegate: MyDelegate()
+)
+
+actor MyDelegate: ToolExecutionDelegate {
+    func confirmDestructiveOperation(_ context: DestructiveOperationContext) async -> Bool {
+        // Show confirmation UI, inspect context.sql, context.targetTable, etc.
+        return true  // or false to reject
+    }
+
+    func willExecuteSQL(_ sql: String, classification: SQLClassification) async {
+        // Observe before execution
+    }
+
+    func didExecuteSQL(_ sql: String, success: Bool) async {
+        // Observe after execution
+    }
+}
+```
+
+---
+
+## 7. Feature Requirements
+
+### P0 — Must Have (v1.0) — All Implemented
+
+| # | Feature | Description | Status |
+|---|---|---|---|
+| F1 | **Schema Discovery** | Auto-introspect all tables, columns (name, type, nullability, defaults), primary keys, foreign keys, and indexes from `sqlite_master` and PRAGMA statements. Zero config — no annotations needed. | Done |
+| F2 | **Natural Language to SQL** | Convert NL queries to SQL via LLM. The LLM generates raw SQL; no `#Predicate` or `FetchDescriptor` — pure SQL throughout. | Done |
+| F3 | **Result Rendering — Text** | `TextSummaryRenderer` uses the LLM to produce natural-language summaries of query results. | Done |
+| F4 | **Result Rendering — Data Tables** | `ScrollableDataTableView` renders query results as scrollable, structured tables in SwiftUI. | Done |
+| F5 | **Result Rendering — Swift Charts** | `ChartDataDetector` auto-detects chart-eligible results. `BarChartView`, `LineChartView`, `PieChartView` render via Swift Charts. | Done |
+| F6 | **Drop-in ChatView** | `DataChatView` (zero-config: path + model) and `ChatView` (full control via `ChatViewModel`). Message bubbles, loading states, error display. | Done |
+| F7 | **AnyLanguageModel Integration** | Uses HuggingFace's AnyLanguageModel for the LLM layer. `LanguageModelSession` for SQL generation and result summarization. | Done |
+| F8 | **SQL Safety — Operation Allowlist** | `OperationAllowlist` with presets (`.readOnly`, `.standard`, `.unrestricted`) and custom sets. Allowlist check only — no SQL parser for safety. | Done |
+| F9 | **SQL Safety — Mutation Policy** | `MutationPolicy` adds per-table restrictions on top of the allowlist. DELETE requires confirmation by default. | Done |
+| F10 | **SQL Safety — Custom Validators** | `QueryValidator` protocol with built-in `TableAllowlistValidator` and `MaxRowLimitValidator`. Extensible for domain-specific rules. | Done |
+| F11 | **Mutation Support** | INSERT, UPDATE, DELETE via SQL with allowlist validation and optional confirmation via `ToolExecutionDelegate`. | Done |
+| F12 | **Conversation Context** | Multi-turn support with configurable context window size. "Show overdue tasks" -> "Now sort them by priority" maintains history. | Done |
+| F13 | **Error Handling** | Typed `SwiftDBAIError` enum covering schema introspection failures, empty schemas, invalid SQL, disallowed operations, confirmation required, database errors, LLM failures, and query timeouts. | Done |
+
+### P1 — Should Have (v1.x)
+
+| # | Feature | Description |
+|---|---|---|
+| F14 | **On-Device Providers** | Guide for using Ollama, CoreML, MLX, or llama.cpp via AnyLanguageModel for fully offline / privacy-sensitive deployments |
+| F15 | **Chat History Persistence** | Optionally persist chat history to SQLite via GRDB |
+| F16 | **Theming API** | Customize colors, fonts, bubble styles, dark/light mode in ChatView |
+| F17 | **Streaming Responses** | Token-by-token display for cloud LLM providers |
+| F18 | **Export Results** | Copy/share query results as CSV, JSON, or formatted text |
+
+### P2 — Nice to Have (v2.0+)
+
+| # | Feature | Description |
+|---|---|---|
+| F19 | **Voice Input** | Speech-to-text for hands-free data queries |
+| F20 | **MCP Server Mode** | Expose any SQLite database as an MCP server so external LLM clients can query it |
+| F21 | **Suggested Questions** | Auto-generate starter questions based on introspected schema |
+| F22 | **Audit Log** | Log all mutations with timestamp, before/after values |
+| F23 | **Multi-Database** | Support querying across multiple SQLite databases simultaneously |
+
+---
+
+## 8. Privacy & Security
+
+| Concern | Approach |
+|---|---|
+| **Provider choice is yours** | Use Ollama or a self-hosted model to keep data off third-party servers |
+| **No telemetry** | The package collects nothing |
+| **API key handling** | Cloud provider keys are never persisted by the kit; developer is responsible for secure storage |
+| **SQL safety** | Developer-configured `OperationAllowlist` controls what SQL the LLM may generate. Allowlist check only — no attempt at SQL parsing for injection prevention. The developer is responsible for setting appropriate allowlist levels. |
+| **Mutation safety** | `MutationPolicy` provides per-table restrictions. DELETE requires explicit confirmation by default via `ToolExecutionDelegate`. |
+| **Data stays in-process** | Query results stay in the GRDB connection; no serialization to disk or network unless developer opts in |
+| **Connection ownership** | Developer manages their own GRDB `DatabasePool`/`DatabaseQueue`. SwiftDBAI never opens, closes, or migrates the database on its own. |
+
+---
+
+## 9. Technical Constraints
+
+- **Swift Package Manager** only (no CocoaPods/Carthage)
+- **Minimum deployments:** iOS 17.0, macOS 14.0, visionOS 1.0
+- **Swift 6.1** language mode with strict concurrency checking
+- **Dependencies:** GRDB.swift 7.0+ and AnyLanguageModel (branch: main)
+- **No UIKit dependency** — pure SwiftUI for the view layer
+- **No SwiftData dependency** — pure GRDB/SQL throughout. Works with any SQLite database regardless of how it was created.
+- **No Core Data dependency** — no ORM layer of any kind
+
+---
+
+## 10. Implementation Status
+
+| Metric | Current |
+|---|---|
+| Source files | 30 |
+| Test files | 19 |
+| Tests passing | 352 |
+| Swift language mode | 6.1 |
+| Dependencies | GRDB.swift 7.0+, AnyLanguageModel |
+
+---
+
+## 11. Success Metrics
+
+| Metric | Target |
+|---|---|
+| Integration time | < 5 minutes for basic "chat with my data" — provide a database path and a model |
+| Query accuracy | > 90% of common queries (SELECT with filters, sorting, aggregates) produce correct SQL on first attempt |
+| Latency (kit overhead) | < 500ms for schema introspection + SQL validation on a typical 20-table database (excludes LLM response time) |
+| Package size | < 2 MB added to app binary (excluding LLM model weights) |
+| Crash rate | 0 crashes from kit code in production |
+
+---
+
+## 12. Open Questions
+
+1. **AnyLanguageModel maturity** — The library is relatively new; we need to track API stability and pin to a specific version. What's our fallback if breaking changes land? (Currently pinned to `branch: main`.)
+2. **SQL injection surface** — The allowlist check validates operation type but does not parse SQL structure. Should we add a lightweight SQL tokenizer for additional safety, or is the allowlist sufficient given the LLM is the only SQL author?
+3. **Schema change detection** — `SchemaIntrospector` caches the schema after first introspection. If the database schema changes at runtime (migrations, etc.), the cache becomes stale. Should we add a `schema_version` PRAGMA check or a manual invalidation API?
+4. **Large schema handling** — For databases with many tables (100+), the schema description in the LLM system prompt may be very large. Should we add table filtering or relevance ranking?
+5. **Chart auto-detection accuracy** — `ChartDataDetector` heuristically determines if results are chart-eligible. How do we handle false positives/negatives?
+
+---
+
+## 13. Milestones
+
+| Milestone | Scope | Status |
+|---|---|---|
+| **M1: Foundation** | SchemaIntrospector + SQLQueryParser + headless ChatEngine | Done |
+| **M2: Safety** | OperationAllowlist + MutationPolicy + QueryValidator + ToolExecutionDelegate | Done |
+| **M3: Chat UI** | DataChatView + ChatView + ChatViewModel + MessageBubbleView + ErrorMessageView | Done |
+| **M4: Rendering** | TextSummaryRenderer + ScrollableDataTableView + ChartDataDetector + Bar/Line/Pie charts | Done |
+| **M5: Multi-turn** | ConversationHistory + context window + PromptBuilder with history | Done |
+| **M6: Polish & Ship** | Error handling (SwiftDBAIError), 352 tests, documentation | Done |
+
+---
+
+## 14. References
+
+- [GRDB.swift](https://github.com/groue/GRDB.swift) — SQLite toolkit for Swift
+- [AnyLanguageModel (HuggingFace)](https://github.com/huggingface/AnyLanguageModel) — Unified Swift LLM abstraction
+- [Swift Charts](https://developer.apple.com/documentation/charts) — Apple's declarative charting framework
+- [Model Context Protocol (MCP)](https://modelcontextprotocol.io) — For future MCP server mode
+- [Swift Package Manager](https://www.swift.org/documentation/package-manager/)
+- [SQLite PRAGMA Statements](https://www.sqlite.org/pragma.html) — Used for schema introspection

Package.swift

@@ -0,0 +1,41 @@
+// swift-tools-version: 6.1
+
+import PackageDescription
+
+let package = Package(
+    name: "SwiftDBAI",
+    platforms: [
+        .iOS(.v17),
+        .macOS(.v14),
+        .visionOS(.v1),
+    ],
+    products: [
+        .library(
+            name: "SwiftDBAI",
+            targets: ["SwiftDBAI"]
+        ),
+    ],
+    dependencies: [
+        .package(url: "https://github.com/groue/GRDB.swift.git", from: "7.0.0"),
+        .package(url: "https://github.com/huggingface/AnyLanguageModel.git", branch: "main"),
+    ],
+    targets: [
+        .target(
+            name: "SwiftDBAI",
+            dependencies: [
+                .product(name: "GRDB", package: "GRDB.swift"),
+                .product(name: "AnyLanguageModel", package: "AnyLanguageModel"),
+            ],
+            swiftSettings: [
+                .swiftLanguageMode(.v6),
+            ]
+        ),
+        .testTarget(
+            name: "SwiftDBAITests",
+            dependencies: ["SwiftDBAI"],
+            swiftSettings: [
+                .swiftLanguageMode(.v6),
+            ]
+        ),
+    ]
+)

README.md

@@ -0,0 +1,254 @@
+# SwiftDBAI
+
+Chat with any SQLite database using natural language.
+
+<!-- badges -->
+![Swift 6.1+](https://img.shields.io/badge/Swift-6.1+-orange.svg)
+![Platforms](https://img.shields.io/badge/Platforms-iOS%2017%20|%20macOS%2014%20|%20visionOS%201-blue.svg)
+![License](https://img.shields.io/badge/License-MIT-green.svg)
+
+## Features
+
+- Drop-in SwiftUI chat view (`DataChatView`) -- one line to add a database chat UI
+- Headless `ChatEngine` for programmatic / non-UI use
+- LLM-agnostic via [AnyLanguageModel](https://github.com/huggingface/AnyLanguageModel) -- works with OpenAI, Anthropic, Gemini, Ollama, llama.cpp, or any OpenAI-compatible endpoint
+- Automatic schema introspection -- no manual annotations required
+- Safety-first: read-only by default, operation allowlists, table-level mutation policies, destructive operation confirmation delegate
+- Configurable query timeouts, context windows, and custom validators
+
+## Installation
+
+Add SwiftDBAI via Swift Package Manager:
+
+```swift
+dependencies: [
+    .package(url: "https://github.com/<org>/SwiftDBAI.git", from: "1.0.0"),
+]
+```
+
+Then add the dependency to your target:
+
+```swift
+.target(
+    name: "MyApp",
+    dependencies: ["SwiftDBAI"]
+)
+```
+
+## Quick Start
+
+Drop a full chat UI into any SwiftUI view with `DataChatView`:
+
+```swift
+import SwiftDBAI
+import AnyLanguageModel
+
+struct ContentView: View {
+    var body: some View {
+        DataChatView(
+            databasePath: "/path/to/mydata.sqlite",
+            model: OllamaLanguageModel(model: "llama3")
+        )
+    }
+}
+```
+
+That's it. `DataChatView` opens the database, introspects the schema, and renders a chat interface. The default mode is **read-only** (SELECT only).
+
+To pass an existing GRDB connection and customize behavior:
+
+```swift
+DataChatView(
+    database: myDatabasePool,
+    model: OpenAILanguageModel(apiKey: "sk-...", model: "gpt-4o"),
+    allowlist: .standard,
+    additionalContext: "This database stores a recipe app's data.",
+    maxSummaryRows: 100
+)
+```
+
+## Headless / Programmatic Use
+
+Use `ChatEngine` directly when you don't need a UI:
+
+```swift
+import SwiftDBAI
+import AnyLanguageModel
+import GRDB
+
+let pool = try DatabasePool(path: "/path/to/mydata.sqlite")
+let engine = ChatEngine(
+    database: pool,
+    model: OpenAILanguageModel(apiKey: "sk-...", model: "gpt-4o")
+)
+
+let response = try await engine.send("How many users signed up this week?")
+print(response.summary)   // "There were 42 new signups this week."
+print(response.sql)        // Optional("SELECT COUNT(*) FROM users WHERE ...")
+```
+
+`ChatEngine` also accepts a `ProviderConfiguration` for convenience:
+
+```swift
+let engine = ChatEngine(
+    database: pool,
+    provider: .anthropic(apiKey: "sk-ant-...", model: "claude-sonnet-4-20250514")
+)
+```
+
+For fine-grained control, pass a `ChatEngineConfiguration`:
+
+```swift
+var config = ChatEngineConfiguration(
+    queryTimeout: 10,
+    contextWindowSize: 20,
+    maxSummaryRows: 100,
+    additionalContext: "The 'status' column uses: 'active', 'inactive', 'suspended'."
+)
+
+let engine = ChatEngine(
+    database: pool,
+    model: model,
+    allowlist: .standard,
+    configuration: config
+)
+```
+
+## Choosing a Provider
+
+SwiftDBAI works with any provider supported by AnyLanguageModel. Use `ProviderConfiguration` factory methods or construct model instances directly.
+
+```swift
+// OpenAI
+let config = ProviderConfiguration.openAI(apiKey: "sk-...", model: "gpt-4o")
+
+// Anthropic
+let config = ProviderConfiguration.anthropic(apiKey: "sk-ant-...", model: "claude-sonnet-4-20250514")
+
+// Gemini
+let config = ProviderConfiguration.gemini(apiKey: "AIza...", model: "gemini-2.0-flash")
+
+// Ollama (local, no API key needed)
+let config = ProviderConfiguration.ollama(model: "llama3.2")
+
+// llama.cpp (local)
+let config = ProviderConfiguration.llamaCpp(model: "default")
+
+// Any OpenAI-compatible endpoint
+let config = ProviderConfiguration.openAICompatible(
+    apiKey: "your-key",
+    model: "llama-3.1-70b",
+    baseURL: URL(string: "https://api.together.xyz/v1/")!
+)
+```
+
+Use with ChatEngine:
+
+```swift
+let engine = ChatEngine(database: pool, provider: config)
+// or
+let engine = ChatEngine(database: pool, model: config.makeModel())
+```
+
+API keys can also come from environment variables:
+
+```swift
+let config = ProviderConfiguration.fromEnvironment(
+    provider: .openAI,
+    environmentVariable: "OPENAI_API_KEY",
+    model: "gpt-4o"
+)
+```
+
+## Safety and Mutation Control
+
+### Operation Allowlist
+
+By default, only SELECT queries are allowed. Opt in to writes explicitly:
+
+| Preset | Allowed Operations |
+|---|---|
+| `.readOnly` (default) | SELECT |
+| `.standard` | SELECT, INSERT, UPDATE |
+| `.unrestricted` | SELECT, INSERT, UPDATE, DELETE |
+
+```swift
+// Custom allowlist
+let allowlist = OperationAllowlist([.select, .insert])
+```
+
+### Mutation Policy
+
+For table-level control, use `MutationPolicy`:
+
+```swift
+// Allow INSERT and UPDATE only on specific tables
+let policy = MutationPolicy(
+    allowedOperations: [.insert, .update],
+    allowedTables: ["orders", "order_items"]
+)
+
+let engine = ChatEngine(
+    database: pool,
+    model: model,
+    mutationPolicy: policy
+)
+```
+
+Presets: `.readOnly`, `.readWrite`, `.unrestricted`.
+
+### Confirmation Delegate
+
+Destructive operations (DELETE, DROP, ALTER, TRUNCATE) require confirmation through a `ToolExecutionDelegate`:
+
+```swift
+struct MyDelegate: ToolExecutionDelegate {
+    func confirmDestructiveOperation(
+        _ context: DestructiveOperationContext
+    ) async -> Bool {
+        // Present confirmation UI, return true to proceed
+        return await showConfirmationDialog(context.description)
+    }
+}
+
+let engine = ChatEngine(
+    database: pool,
+    model: model,
+    allowlist: .unrestricted,
+    delegate: MyDelegate()
+)
+```
+
+Without a delegate, destructive operations throw `SwiftDBAIError.confirmationRequired` so you can handle confirmation in your own flow.
+
+Built-in delegates: `AutoApproveDelegate` (testing only), `RejectAllDelegate` (safest).
+
+## Architecture
+
+```
+User Question
+    |
+    v
+ChatEngine
+    |-- SchemaIntrospector   (auto-discovers tables, columns, keys, indexes)
+    |-- PromptBuilder        (builds LLM system prompt with schema context)
+    |-- LanguageModel        (generates SQL via AnyLanguageModel)
+    |-- SQLQueryParser       (parses and validates against allowlist/policy)
+    |-- QueryValidator       (optional custom validators)
+    |-- GRDB                 (executes SQL against SQLite)
+    |-- TextSummaryRenderer  (summarizes results via LLM)
+    v
+ChatResponse { summary, sql, queryResult }
+```
+
+`DataChatView` wraps this pipeline in a SwiftUI view with `ChatViewModel` managing state.
+
+## Requirements
+
+- iOS 17.0+ / macOS 14.0+ / visionOS 1.0+
+- Swift 6.1+
+- Xcode 16+
+
+## License
+
+MIT. See [LICENSE](LICENSE) for details.

Sources/SwiftDBAI/Config/ChatEngineConfiguration.swift

@@ -0,0 +1,113 @@
+// ChatEngineConfiguration.swift
+// SwiftDBAI
+//
+// Configurable settings for ChatEngine behavior — timeouts, context window,
+// summary limits, and custom query validation.
+
+import Foundation
+
+/// Configuration for ``ChatEngine`` behavior.
+///
+/// Use this to tune timeouts, conversation context windows, and attach
+/// custom query validators.
+///
+/// ```swift
+/// var config = ChatEngineConfiguration()
+/// config.queryTimeout = 10        // 10-second SQL timeout
+/// config.contextWindowSize = 20   // Keep last 20 messages for LLM context
+/// config.maxSummaryRows = 100     // Summarize up to 100 rows
+///
+/// let engine = ChatEngine(
+///     database: db,
+///     model: model,
+///     configuration: config
+/// )
+/// ```
+public struct ChatEngineConfiguration: Sendable {
+
+    // MARK: - Query Execution
+
+    /// Maximum time (in seconds) to wait for a SQL query to execute.
+    ///
+    /// If the query exceeds this duration, a ``ChatEngineError/queryTimedOut``
+    /// error is thrown. Set to `nil` to disable the timeout (not recommended
+    /// for user-facing apps). Defaults to 30 seconds.
+    public var queryTimeout: TimeInterval?
+
+    // MARK: - Conversation Context
+
+    /// Maximum number of conversation messages to include when building
+    /// LLM context for follow-up queries.
+    ///
+    /// Only the most recent `contextWindowSize` messages are sent to the LLM.
+    /// Older messages are still retained in ``ChatEngine/messages`` for UI
+    /// display but do not consume LLM tokens.
+    ///
+    /// Set to `nil` for unlimited context (all history is always sent).
+    /// Defaults to 50 messages.
+    public var contextWindowSize: Int?
+
+    // MARK: - Rendering
+
+    /// Maximum number of rows to include when generating text summaries.
+    /// Defaults to 50.
+    public var maxSummaryRows: Int
+
+    // MARK: - LLM Context
+
+    /// Optional extra instructions appended to the LLM system prompt.
+    ///
+    /// Use this to provide business-specific terminology, query hints,
+    /// or domain constraints. For example:
+    /// ```swift
+    /// config.additionalContext = "The 'status' column uses: 'active', 'inactive', 'suspended'."
+    /// ```
+    public var additionalContext: String?
+
+    // MARK: - Validation
+
+    /// Custom query validators that run after the built-in allowlist check.
+    ///
+    /// Use ``addValidator(_:)`` to add validators. They are executed in order;
+    /// the first validator to throw stops execution.
+    public private(set) var validators: [any QueryValidator] = []
+
+    // MARK: - Initialization
+
+    /// Creates a configuration with the given settings.
+    ///
+    /// - Parameters:
+    ///   - queryTimeout: SQL execution timeout in seconds. Defaults to 30.
+    ///   - contextWindowSize: Max messages for LLM context. Defaults to 50.
+    ///   - maxSummaryRows: Max rows for text summaries. Defaults to 50.
+    ///   - additionalContext: Extra LLM system prompt instructions.
+    public init(
+        queryTimeout: TimeInterval? = 30,
+        contextWindowSize: Int? = 50,
+        maxSummaryRows: Int = 50,
+        additionalContext: String? = nil
+    ) {
+        self.queryTimeout = queryTimeout
+        self.contextWindowSize = contextWindowSize
+        self.maxSummaryRows = maxSummaryRows
+        self.additionalContext = additionalContext
+    }
+
+    /// The default configuration: 30s timeout, 50-message context window,
+    /// 50-row summaries, no additional context, no custom validators.
+    public static let `default` = ChatEngineConfiguration()
+
+    // MARK: - Mutating Helpers
+
+    /// Appends a custom query validator.
+    ///
+    /// Validators run after the built-in allowlist and dangerous-keyword checks.
+    /// They receive the parsed SQL and can throw to reject a query.
+    ///
+    /// ```swift
+    /// config.addValidator(TableAllowlistValidator(allowedTables: ["users", "orders"]))
+    /// ```
+    public mutating func addValidator(_ validator: any QueryValidator) {
+        validators.append(validator)
+    }
+}

Sources/SwiftDBAI/Config/LocalProviderConfiguration.swift

@@ -0,0 +1,336 @@
+// LocalProviderConfiguration.swift
+// SwiftDBAI
+//
+// Configuration and endpoint discovery for local/self-hosted LLM providers
+// (Ollama, llama.cpp). Wraps AnyLanguageModel's OllamaLanguageModel and
+// OpenAILanguageModel with convenient factory methods and health checking.
+
+import AnyLanguageModel
+import Foundation
+
+#if canImport(FoundationNetworking)
+    import FoundationNetworking
+#endif
+
+// MARK: - Local Provider Endpoint
+
+/// Represents a discovered local LLM endpoint with its connection status.
+public struct LocalProviderEndpoint: Sendable, Equatable {
+    /// The base URL of the local provider.
+    public let baseURL: URL
+
+    /// The provider type (Ollama or llama.cpp).
+    public let providerType: LocalProviderType
+
+    /// Whether the endpoint was reachable at discovery time.
+    public let isReachable: Bool
+
+    /// The list of available models, if the endpoint supports model listing.
+    public let availableModels: [String]
+
+    /// Human-readable description of the endpoint.
+    public var description: String {
+        let status = isReachable ? "reachable" : "unreachable"
+        return "\(providerType.rawValue) at \(baseURL.absoluteString) (\(status), \(availableModels.count) models)"
+    }
+}
+
+/// The type of local LLM provider.
+public enum LocalProviderType: String, Sendable, Hashable, CaseIterable {
+    /// Ollama — runs models locally via `ollama serve`.
+    /// Default endpoint: http://localhost:11434
+    case ollama
+
+    /// llama.cpp server — runs GGUF models via `llama-server`.
+    /// Default endpoint: http://localhost:8080
+    /// Exposes an OpenAI-compatible API.
+    case llamaCpp = "llama.cpp"
+}
+
+// MARK: - Local Provider Discovery
+
+/// Discovers and validates local LLM provider endpoints.
+///
+/// Use `LocalProviderDiscovery` to automatically find running Ollama or llama.cpp
+/// instances on the local machine, check their health, and list available models.
+///
+/// ```swift
+/// // Check if Ollama is running
+/// let isRunning = await LocalProviderDiscovery.isOllamaRunning()
+///
+/// // Discover all local providers
+/// let endpoints = await LocalProviderDiscovery.discoverAll()
+/// for endpoint in endpoints where endpoint.isReachable {
+///     print("Found \(endpoint.description)")
+/// }
+///
+/// // List models available on Ollama
+/// let models = await LocalProviderDiscovery.listOllamaModels()
+/// ```
+public enum LocalProviderDiscovery {
+
+    /// Default Ollama endpoint.
+    public static let defaultOllamaURL = URL(string: "http://localhost:11434")!
+
+    /// Default llama.cpp server endpoint.
+    public static let defaultLlamaCppURL = URL(string: "http://localhost:8080")!
+
+    /// Well-known ports to probe for local providers.
+    /// Ollama: 11434, llama.cpp: 8080
+    private static let wellKnownEndpoints: [(URL, LocalProviderType)] = [
+        (defaultOllamaURL, .ollama),
+        (defaultLlamaCppURL, .llamaCpp),
+    ]
+
+    // MARK: - Health Checks
+
+    /// Checks if an Ollama instance is reachable at the given URL.
+    ///
+    /// Sends a GET request to the Ollama root endpoint and checks for a 200 response.
+    ///
+    /// - Parameter baseURL: The Ollama base URL. Defaults to `http://localhost:11434`.
+    /// - Parameter timeout: Connection timeout in seconds. Defaults to 3.
+    /// - Returns: `true` if the Ollama server responded successfully.
+    public static func isOllamaRunning(
+        at baseURL: URL = defaultOllamaURL,
+        timeout: TimeInterval = 3
+    ) async -> Bool {
+        await checkEndpointHealth(baseURL, timeout: timeout)
+    }
+
+    /// Checks if a llama.cpp server is reachable at the given URL.
+    ///
+    /// Sends a GET request to the `/health` endpoint and checks for a 200 response.
+    ///
+    /// - Parameter baseURL: The llama.cpp base URL. Defaults to `http://localhost:8080`.
+    /// - Parameter timeout: Connection timeout in seconds. Defaults to 3.
+    /// - Returns: `true` if the llama.cpp server responded successfully.
+    public static func isLlamaCppRunning(
+        at baseURL: URL = defaultLlamaCppURL,
+        timeout: TimeInterval = 3
+    ) async -> Bool {
+        let healthURL = baseURL.appendingPathComponent("health")
+        return await checkEndpointHealth(healthURL, timeout: timeout)
+    }
+
+    /// Checks if any endpoint at the given URL responds to HTTP requests.
+    ///
+    /// - Parameters:
+    ///   - url: The URL to probe.
+    ///   - timeout: Connection timeout in seconds.
+    /// - Returns: `true` if the endpoint returned an HTTP response with status 200.
+    private static func checkEndpointHealth(
+        _ url: URL,
+        timeout: TimeInterval
+    ) async -> Bool {
+        let config = URLSessionConfiguration.ephemeral
+        config.timeoutIntervalForRequest = timeout
+        config.timeoutIntervalForResource = timeout
+        let session = URLSession(configuration: config)
+
+        do {
+            let (_, response) = try await session.data(from: url)
+            if let httpResponse = response as? HTTPURLResponse {
+                return httpResponse.statusCode == 200
+            }
+            return false
+        } catch {
+            return false
+        }
+    }
+
+    // MARK: - Model Listing
+
+    /// Lists models available on an Ollama instance.
+    ///
+    /// Calls the Ollama `/api/tags` endpoint to retrieve the list of
+    /// locally installed models.
+    ///
+    /// - Parameter baseURL: The Ollama base URL. Defaults to `http://localhost:11434`.
+    /// - Parameter timeout: Request timeout in seconds. Defaults to 5.
+    /// - Returns: An array of model name strings, or an empty array if unreachable.
+    public static func listOllamaModels(
+        at baseURL: URL = defaultOllamaURL,
+        timeout: TimeInterval = 5
+    ) async -> [String] {
+        let tagsURL = baseURL.appendingPathComponent("api/tags")
+        let config = URLSessionConfiguration.ephemeral
+        config.timeoutIntervalForRequest = timeout
+        config.timeoutIntervalForResource = timeout
+        let session = URLSession(configuration: config)
+
+        do {
+            let (data, response) = try await session.data(from: tagsURL)
+            guard let httpResponse = response as? HTTPURLResponse,
+                  httpResponse.statusCode == 200
+            else {
+                return []
+            }
+
+            let decoded = try JSONDecoder().decode(OllamaTagsResponse.self, from: data)
+            return decoded.models.map(\.name)
+        } catch {
+            return []
+        }
+    }
+
+    /// Lists models available on a llama.cpp server via its OpenAI-compatible endpoint.
+    ///
+    /// Calls `/v1/models` which llama.cpp exposes when running with
+    /// `--api-key` or in default mode.
+    ///
+    /// - Parameter baseURL: The llama.cpp base URL. Defaults to `http://localhost:8080`.
+    /// - Parameter timeout: Request timeout in seconds. Defaults to 5.
+    /// - Returns: An array of model ID strings, or an empty array if unreachable.
+    public static func listLlamaCppModels(
+        at baseURL: URL = defaultLlamaCppURL,
+        timeout: TimeInterval = 5
+    ) async -> [String] {
+        let modelsURL = baseURL.appendingPathComponent("v1/models")
+        let config = URLSessionConfiguration.ephemeral
+        config.timeoutIntervalForRequest = timeout
+        config.timeoutIntervalForResource = timeout
+        let session = URLSession(configuration: config)
+
+        do {
+            let (data, response) = try await session.data(from: modelsURL)
+            guard let httpResponse = response as? HTTPURLResponse,
+                  httpResponse.statusCode == 200
+            else {
+                return []
+            }
+
+            let decoded = try JSONDecoder().decode(OpenAIModelsResponse.self, from: data)
+            return decoded.data.map(\.id)
+        } catch {
+            return []
+        }
+    }
+
+    // MARK: - Full Discovery
+
+    /// Discovers all running local LLM providers by probing well-known endpoints.
+    ///
+    /// Probes Ollama (port 11434) and llama.cpp (port 8080) concurrently,
+    /// returning their status and available models.
+    ///
+    /// ```swift
+    /// let endpoints = await LocalProviderDiscovery.discoverAll()
+    /// for endpoint in endpoints where endpoint.isReachable {
+    ///     print("Found: \(endpoint.description)")
+    /// }
+    /// ```
+    ///
+    /// - Parameter timeout: Connection timeout per endpoint in seconds. Defaults to 3.
+    /// - Returns: An array of `LocalProviderEndpoint` for each probed location.
+    public static func discoverAll(
+        timeout: TimeInterval = 3
+    ) async -> [LocalProviderEndpoint] {
+        await withTaskGroup(of: LocalProviderEndpoint.self, returning: [LocalProviderEndpoint].self) { group in
+            for (url, providerType) in wellKnownEndpoints {
+                group.addTask {
+                    await discover(providerType: providerType, at: url, timeout: timeout)
+                }
+            }
+
+            var results: [LocalProviderEndpoint] = []
+            for await endpoint in group {
+                results.append(endpoint)
+            }
+            return results
+        }
+    }
+
+    /// Discovers a specific local provider at the given URL.
+    ///
+    /// - Parameters:
+    ///   - providerType: The type of provider to probe.
+    ///   - baseURL: The base URL to check.
+    ///   - timeout: Connection timeout in seconds.
+    /// - Returns: A `LocalProviderEndpoint` with reachability and model info.
+    public static func discover(
+        providerType: LocalProviderType,
+        at baseURL: URL,
+        timeout: TimeInterval = 3
+    ) async -> LocalProviderEndpoint {
+        switch providerType {
+        case .ollama:
+            let reachable = await isOllamaRunning(at: baseURL, timeout: timeout)
+            let models = reachable ? await listOllamaModels(at: baseURL) : []
+            return LocalProviderEndpoint(
+                baseURL: baseURL,
+                providerType: .ollama,
+                isReachable: reachable,
+                availableModels: models
+            )
+
+        case .llamaCpp:
+            let reachable = await isLlamaCppRunning(at: baseURL, timeout: timeout)
+            let models = reachable ? await listLlamaCppModels(at: baseURL) : []
+            return LocalProviderEndpoint(
+                baseURL: baseURL,
+                providerType: .llamaCpp,
+                isReachable: reachable,
+                availableModels: models
+            )
+        }
+    }
+
+    /// Discovers a specific local provider at a custom URL and port.
+    ///
+    /// Use this for non-standard configurations where Ollama or llama.cpp
+    /// is running on a custom host or port.
+    ///
+    /// ```swift
+    /// let endpoint = await LocalProviderDiscovery.discover(
+    ///     providerType: .ollama,
+    ///     host: "192.168.1.100",
+    ///     port: 11434
+    /// )
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - providerType: The provider type.
+    ///   - host: The hostname or IP address.
+    ///   - port: The port number.
+    ///   - timeout: Connection timeout in seconds. Defaults to 3.
+    /// - Returns: A `LocalProviderEndpoint` with reachability and model info.
+    public static func discover(
+        providerType: LocalProviderType,
+        host: String,
+        port: Int,
+        timeout: TimeInterval = 3
+    ) async -> LocalProviderEndpoint {
+        guard let url = URL(string: "http://\(host):\(port)") else {
+            return LocalProviderEndpoint(
+                baseURL: URL(string: "http://\(host):\(port)")!,
+                providerType: providerType,
+                isReachable: false,
+                availableModels: []
+            )
+        }
+        return await discover(providerType: providerType, at: url, timeout: timeout)
+    }
+}
+
+// MARK: - JSON Response Types
+
+/// Response from Ollama's `/api/tags` endpoint.
+private struct OllamaTagsResponse: Decodable, Sendable {
+    let models: [OllamaModelInfo]
+}
+
+/// Individual model info from Ollama's tags endpoint.
+private struct OllamaModelInfo: Decodable, Sendable {
+    let name: String
+}
+
+/// Response from the OpenAI-compatible `/v1/models` endpoint.
+private struct OpenAIModelsResponse: Decodable, Sendable {
+    let data: [OpenAIModelInfo]
+}
+
+/// Individual model info from the OpenAI models endpoint.
+private struct OpenAIModelInfo: Decodable, Sendable {
+    let id: String
+}

Sources/SwiftDBAI/Config/MutationPolicy.swift

@@ -0,0 +1,148 @@
+// MutationPolicy.swift
+// SwiftDBAI
+//
+// Defines which mutation operations are permitted and optionally restricts
+// them to specific tables. Wraps OperationAllowlist with table-level granularity.
+
+import Foundation
+
+/// Controls which SQL mutation operations the LLM may generate and,
+/// optionally, which tables those mutations may target.
+///
+/// `MutationPolicy` builds on ``OperationAllowlist`` by adding per-table
+/// restrictions. The default policy is **read-only** — no mutations are
+/// allowed on any table. Write operations require explicit opt-in.
+///
+/// ```swift
+/// // Read-only (default) — only SELECT is allowed
+/// let readOnly = MutationPolicy.readOnly
+///
+/// // Allow INSERT and UPDATE on specific tables only
+/// let restricted = MutationPolicy(
+///     allowedOperations: [.insert, .update],
+///     allowedTables: ["orders", "order_items"]
+/// )
+///
+/// // Allow INSERT and UPDATE on all tables
+/// let broad = MutationPolicy(allowedOperations: [.insert, .update])
+///
+/// // Full access including DELETE (requires confirmation)
+/// let full = MutationPolicy.unrestricted
+/// ```
+public struct MutationPolicy: Sendable, Equatable {
+
+    // MARK: - Properties
+
+    /// The underlying operation allowlist (always includes SELECT).
+    public let operationAllowlist: OperationAllowlist
+
+    /// Optional set of table names that mutations may target.
+    ///
+    /// When `nil`, mutations are allowed on all tables (subject to
+    /// ``operationAllowlist``). When non-nil, mutation operations
+    /// (INSERT, UPDATE, DELETE) are only permitted on the listed tables.
+    /// SELECT queries are never restricted by this property.
+    public let allowedMutationTables: Set<String>?
+
+    /// When `true`, destructive operations (DELETE) require explicit user
+    /// confirmation before execution, even when the operation is allowed.
+    /// Defaults to `true`.
+    public let requiresDestructiveConfirmation: Bool
+
+    // MARK: - Initialization
+
+    /// Creates a mutation policy with the given operations and optional table restrictions.
+    ///
+    /// SELECT is always implicitly included — you cannot create a policy
+    /// that disallows reads.
+    ///
+    /// - Parameters:
+    ///   - allowedOperations: The mutation operations to permit (INSERT, UPDATE, DELETE).
+    ///     SELECT is always allowed regardless of this parameter.
+    ///   - allowedTables: Optional set of table names mutations may target.
+    ///     Pass `nil` to allow mutations on all tables. Defaults to `nil`.
+    ///   - requiresDestructiveConfirmation: Whether DELETE requires user confirmation.
+    ///     Defaults to `true`.
+    public init(
+        allowedOperations: Set<SQLOperation> = [],
+        allowedTables: Set<String>? = nil,
+        requiresDestructiveConfirmation: Bool = true
+    ) {
+        // Always include SELECT
+        var ops = allowedOperations
+        ops.insert(.select)
+        self.operationAllowlist = OperationAllowlist(ops)
+        self.allowedMutationTables = allowedTables
+        self.requiresDestructiveConfirmation = requiresDestructiveConfirmation
+    }
+
+    // MARK: - Presets
+
+    /// Read-only policy: only SELECT queries are allowed. This is the default.
+    public static let readOnly = MutationPolicy()
+
+    /// Standard read-write: SELECT, INSERT, and UPDATE on all tables.
+    public static let readWrite = MutationPolicy(
+        allowedOperations: [.insert, .update]
+    )
+
+    /// Unrestricted: all operations including DELETE on all tables.
+    /// DELETE still requires confirmation by default.
+    public static let unrestricted = MutationPolicy(
+        allowedOperations: [.insert, .update, .delete]
+    )
+
+    // MARK: - Validation
+
+    /// Returns `true` if the given operation is permitted by this policy.
+    public func isOperationAllowed(_ operation: SQLOperation) -> Bool {
+        operationAllowlist.isAllowed(operation)
+    }
+
+    /// Returns `true` if the given mutation operation is permitted on the
+    /// specified table.
+    ///
+    /// SELECT operations always return `true` regardless of table restrictions.
+    /// For mutation operations, this checks both the operation allowlist and
+    /// the table restrictions (if any).
+    ///
+    /// - Parameters:
+    ///   - operation: The SQL operation type.
+    ///   - table: The target table name (case-insensitive comparison).
+    /// - Returns: Whether the operation is allowed on the given table.
+    public func isAllowed(operation: SQLOperation, on table: String) -> Bool {
+        // SELECT is always allowed
+        guard operation != .select else { return true }
+
+        // Check operation allowlist first
+        guard operationAllowlist.isAllowed(operation) else { return false }
+
+        // If no table restrictions, the operation is allowed
+        guard let allowedTables = allowedMutationTables else { return true }
+
+        // Case-insensitive table name check
+        let lowerTable = table.lowercased()
+        return allowedTables.contains { $0.lowercased() == lowerTable }
+    }
+
+    /// Returns `true` if the given operation requires user confirmation.
+    public func requiresConfirmation(for operation: SQLOperation) -> Bool {
+        operation == .delete && requiresDestructiveConfirmation
+    }
+
+    /// Returns a human-readable description for inclusion in the LLM system prompt.
+    func describeForLLM() -> String {
+        var desc = operationAllowlist.describeForLLM()
+
+        if let tables = allowedMutationTables, !tables.isEmpty {
+            let sorted = tables.sorted()
+            desc += " Mutations (INSERT/UPDATE/DELETE) are restricted to these tables only: \(sorted.joined(separator: ", "))."
+        }
+
+        if requiresDestructiveConfirmation && operationAllowlist.isAllowed(.delete) {
+            desc += " DELETE operations require user confirmation before execution."
+        }
+
+        return desc
+    }
+}

Sources/SwiftDBAI/Config/OnDeviceProviderConfiguration.swift

@@ -0,0 +1,866 @@
+// OnDeviceProviderConfiguration.swift
+// SwiftDBAI
+//
+// Configuration for on-device LLM providers (CoreML, MLX) that run models
+// locally on Apple silicon. These providers enable fully offline,
+// privacy-sensitive deployments where no data leaves the device.
+//
+// Both CoreML and MLX models are provided by AnyLanguageModel behind
+// conditional compilation flags (#if CoreML, #if MLX). This configuration
+// layer wraps their setup with convenient factory methods and integrates
+// them into the SwiftDBAI ChatEngine pipeline.
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+
+// MARK: - On-Device Provider Type
+
+/// The type of on-device LLM provider.
+public enum OnDeviceProviderType: String, Sendable, Hashable, CaseIterable {
+    /// CoreML — runs compiled .mlmodelc models on-device using Apple's CoreML framework.
+    /// Requires pre-compiled models and supports CPU, GPU, and Neural Engine compute units.
+    case coreML
+
+    /// MLX — runs HuggingFace models on Apple silicon using the MLX framework.
+    /// Models are automatically downloaded and cached. Supports quantized models
+    /// (e.g., 4-bit) for efficient memory usage.
+    case mlx
+}
+
+// MARK: - CoreML Configuration
+
+/// Configuration for loading and running a CoreML language model on-device.
+///
+/// CoreML models must be pre-compiled to `.mlmodelc` format before use.
+/// The model runs entirely on-device using CPU, GPU, and/or Neural Engine
+/// depending on the `computeUnits` setting.
+///
+/// ```swift
+/// let config = CoreMLProviderConfiguration(
+///     modelURL: Bundle.main.url(forResource: "MyModel", withExtension: "mlmodelc")!,
+///     computeUnits: .all
+/// )
+/// ```
+///
+/// - Note: CoreML models are available behind the `#if CoreML` flag in AnyLanguageModel.
+///   Ensure your project enables the CoreML build condition.
+public struct CoreMLProviderConfiguration: Sendable, Equatable {
+
+    /// The URL to the compiled CoreML model (`.mlmodelc`).
+    public let modelURL: URL
+
+    /// The compute units to use for inference.
+    ///
+    /// - `.all`: Uses the best available hardware (Neural Engine, GPU, CPU).
+    /// - `.cpuOnly`: Forces CPU-only inference. Useful for debugging.
+    /// - `.cpuAndGPU`: Uses CPU and GPU but not the Neural Engine.
+    /// - `.cpuAndNeuralEngine`: Uses CPU and Neural Engine.
+    public let computeUnits: ComputeUnitPreference
+
+    /// Maximum number of tokens the model can generate per response.
+    /// Defaults to 2048.
+    public let maxResponseTokens: Int
+
+    /// Whether to use sampling (true) or greedy decoding (false).
+    /// Defaults to false (greedy) for more deterministic SQL generation.
+    public let useSampling: Bool
+
+    /// Temperature for sampling. Only used when `useSampling` is true.
+    /// Lower values produce more focused output. Defaults to 0.1.
+    public let temperature: Double
+
+    /// Creates a CoreML provider configuration.
+    ///
+    /// - Parameters:
+    ///   - modelURL: The URL to a compiled CoreML model (`.mlmodelc`).
+    ///   - computeUnits: The compute units to use. Defaults to `.all`.
+    ///   - maxResponseTokens: Maximum tokens per response. Defaults to 2048.
+    ///   - useSampling: Whether to use sampling vs greedy decoding. Defaults to false.
+    ///   - temperature: Sampling temperature. Defaults to 0.1.
+    public init(
+        modelURL: URL,
+        computeUnits: ComputeUnitPreference = .all,
+        maxResponseTokens: Int = 2048,
+        useSampling: Bool = false,
+        temperature: Double = 0.1
+    ) {
+        self.modelURL = modelURL
+        self.computeUnits = computeUnits
+        self.maxResponseTokens = maxResponseTokens
+        self.useSampling = useSampling
+        self.temperature = temperature
+    }
+
+    /// Validates that the model URL points to a compiled CoreML model.
+    ///
+    /// - Throws: ``OnDeviceProviderError`` if the URL is invalid.
+    public func validate() throws {
+        guard modelURL.pathExtension == "mlmodelc" else {
+            throw OnDeviceProviderError.invalidModelFormat(
+                expected: ".mlmodelc",
+                actual: modelURL.pathExtension
+            )
+        }
+
+        guard FileManager.default.fileExists(atPath: modelURL.path) else {
+            throw OnDeviceProviderError.modelNotFound(modelURL)
+        }
+    }
+}
+
+/// Compute unit preference for CoreML inference.
+///
+/// Maps to `MLComputeUnits` in the CoreML framework.
+public enum ComputeUnitPreference: String, Sendable, Hashable, CaseIterable {
+    /// Use all available compute units (Neural Engine, GPU, CPU).
+    /// This is the recommended setting for production use.
+    case all
+
+    /// Force CPU-only execution. Useful for debugging or testing.
+    case cpuOnly
+
+    /// Use CPU and GPU, but not the Neural Engine.
+    case cpuAndGPU
+
+    /// Use CPU and Neural Engine, but not the GPU.
+    case cpuAndNeuralEngine
+}
+
+// MARK: - MLX Configuration
+
+/// Configuration for loading and running an MLX language model on Apple silicon.
+///
+/// MLX models are loaded from HuggingFace Hub or a local directory. The MLX
+/// framework provides efficient inference on Apple silicon with support for
+/// quantized models (4-bit, 8-bit) for reduced memory usage.
+///
+/// ```swift
+/// // From HuggingFace Hub (auto-downloaded)
+/// let config = MLXProviderConfiguration(
+///     modelId: "mlx-community/Llama-3.2-3B-Instruct-4bit"
+/// )
+///
+/// // From a local directory
+/// let config = MLXProviderConfiguration(
+///     modelId: "my-local-model",
+///     localDirectory: URL(fileURLWithPath: "/path/to/model")
+/// )
+/// ```
+///
+/// - Note: MLX models are available behind the `#if MLX` flag in AnyLanguageModel.
+///   Ensure your project enables the MLX build condition.
+public struct MLXProviderConfiguration: Sendable, Equatable {
+
+    /// The HuggingFace model identifier (e.g., "mlx-community/Llama-3.2-3B-Instruct-4bit").
+    public let modelId: String
+
+    /// Optional local directory containing the model files.
+    /// When set, the model is loaded from this directory instead of downloading from Hub.
+    public let localDirectory: URL?
+
+    /// GPU memory management configuration.
+    public let gpuMemory: MLXGPUMemoryConfig
+
+    /// Maximum number of tokens the model can generate per response.
+    /// Defaults to 2048.
+    public let maxResponseTokens: Int
+
+    /// Temperature for text generation. Lower values produce more deterministic output.
+    /// Defaults to 0.1 for SQL generation accuracy.
+    public let temperature: Double
+
+    /// Top-P (nucleus) sampling threshold. Only tokens with cumulative probability
+    /// below this threshold are considered. Defaults to 0.95.
+    public let topP: Double
+
+    /// Repetition penalty to reduce repetitive output. Defaults to 1.1.
+    public let repetitionPenalty: Double
+
+    /// Creates an MLX provider configuration.
+    ///
+    /// - Parameters:
+    ///   - modelId: The HuggingFace model ID or local identifier.
+    ///   - localDirectory: Optional path to a local model directory.
+    ///   - gpuMemory: GPU memory configuration. Defaults to `.automatic`.
+    ///   - maxResponseTokens: Maximum tokens per response. Defaults to 2048.
+    ///   - temperature: Generation temperature. Defaults to 0.1.
+    ///   - topP: Top-P sampling threshold. Defaults to 0.95.
+    ///   - repetitionPenalty: Repetition penalty. Defaults to 1.1.
+    public init(
+        modelId: String,
+        localDirectory: URL? = nil,
+        gpuMemory: MLXGPUMemoryConfig = .automatic,
+        maxResponseTokens: Int = 2048,
+        temperature: Double = 0.1,
+        topP: Double = 0.95,
+        repetitionPenalty: Double = 1.1
+    ) {
+        self.modelId = modelId
+        self.localDirectory = localDirectory
+        self.gpuMemory = gpuMemory
+        self.maxResponseTokens = maxResponseTokens
+        self.temperature = temperature
+        self.topP = topP
+        self.repetitionPenalty = repetitionPenalty
+    }
+
+    /// Validates the configuration parameters.
+    ///
+    /// - Throws: ``OnDeviceProviderError`` if the configuration is invalid.
+    public func validate() throws {
+        guard !modelId.isEmpty else {
+            throw OnDeviceProviderError.emptyModelId
+        }
+
+        if let dir = localDirectory {
+            guard FileManager.default.fileExists(atPath: dir.path) else {
+                throw OnDeviceProviderError.modelNotFound(dir)
+            }
+        }
+
+        guard temperature >= 0 else {
+            throw OnDeviceProviderError.invalidParameter(
+                name: "temperature",
+                value: "\(temperature)",
+                reason: "Must be non-negative"
+            )
+        }
+
+        guard topP > 0, topP <= 1.0 else {
+            throw OnDeviceProviderError.invalidParameter(
+                name: "topP",
+                value: "\(topP)",
+                reason: "Must be between 0 (exclusive) and 1.0 (inclusive)"
+            )
+        }
+
+        guard repetitionPenalty > 0 else {
+            throw OnDeviceProviderError.invalidParameter(
+                name: "repetitionPenalty",
+                value: "\(repetitionPenalty)",
+                reason: "Must be positive"
+            )
+        }
+    }
+
+    // MARK: - Well-Known Models
+
+    /// Pre-configured for Llama 3.2 3B Instruct (4-bit quantized).
+    /// Good balance of quality and memory usage (~2GB RAM).
+    public static func llama3_2_3B(
+        localDirectory: URL? = nil,
+        gpuMemory: MLXGPUMemoryConfig = .automatic
+    ) -> MLXProviderConfiguration {
+        MLXProviderConfiguration(
+            modelId: "mlx-community/Llama-3.2-3B-Instruct-4bit",
+            localDirectory: localDirectory,
+            gpuMemory: gpuMemory,
+            maxResponseTokens: 2048,
+            temperature: 0.1
+        )
+    }
+
+    /// Pre-configured for Qwen 2.5 Coder 3B Instruct (4-bit quantized).
+    /// Optimized for code and SQL generation.
+    public static func qwen2_5_coder_3B(
+        localDirectory: URL? = nil,
+        gpuMemory: MLXGPUMemoryConfig = .automatic
+    ) -> MLXProviderConfiguration {
+        MLXProviderConfiguration(
+            modelId: "mlx-community/Qwen2.5-Coder-3B-Instruct-4bit",
+            localDirectory: localDirectory,
+            gpuMemory: gpuMemory,
+            maxResponseTokens: 2048,
+            temperature: 0.05
+        )
+    }
+
+    /// Pre-configured for Phi-3.5 Mini Instruct (4-bit quantized).
+    /// Compact model suitable for devices with limited memory (~1.5GB RAM).
+    public static func phi3_5_mini(
+        localDirectory: URL? = nil,
+        gpuMemory: MLXGPUMemoryConfig = .automatic
+    ) -> MLXProviderConfiguration {
+        MLXProviderConfiguration(
+            modelId: "mlx-community/Phi-3.5-mini-instruct-4bit",
+            localDirectory: localDirectory,
+            gpuMemory: gpuMemory,
+            maxResponseTokens: 2048,
+            temperature: 0.1
+        )
+    }
+}
+
+/// GPU memory management configuration for MLX models.
+///
+/// Controls how aggressively the MLX runtime manages GPU buffer caches
+/// during active generation and idle phases.
+public struct MLXGPUMemoryConfig: Sendable, Equatable {
+    /// GPU cache limit (in bytes) during active generation.
+    public let activeCacheLimit: Int
+
+    /// GPU cache limit (in bytes) when idle.
+    public let idleCacheLimit: Int
+
+    /// Whether to clear cached GPU buffers when eviction is safe.
+    public let clearCacheOnEviction: Bool
+
+    /// Creates a GPU memory configuration.
+    ///
+    /// - Parameters:
+    ///   - activeCacheLimit: Cache limit during active generation (bytes).
+    ///   - idleCacheLimit: Cache limit when idle (bytes).
+    ///   - clearCacheOnEviction: Whether to clear cache on eviction.
+    public init(
+        activeCacheLimit: Int,
+        idleCacheLimit: Int,
+        clearCacheOnEviction: Bool = true
+    ) {
+        self.activeCacheLimit = activeCacheLimit
+        self.idleCacheLimit = idleCacheLimit
+        self.clearCacheOnEviction = clearCacheOnEviction
+    }
+
+    /// Automatically determined based on device physical memory.
+    ///
+    /// - Devices with <4GB RAM: 128MB active cache
+    /// - Devices with <6GB RAM: 256MB active cache
+    /// - Devices with <8GB RAM: 512MB active cache
+    /// - Devices with 8GB+ RAM: 768MB active cache
+    /// - Idle cache: 50MB for all devices
+    public static var automatic: MLXGPUMemoryConfig {
+        let ramBytes = ProcessInfo.processInfo.physicalMemory
+        let ramGB = ramBytes / (1024 * 1024 * 1024)
+        let active: Int
+        switch ramGB {
+        case ..<4:
+            active = 128_000_000
+        case ..<6:
+            active = 256_000_000
+        case ..<8:
+            active = 512_000_000
+        default:
+            active = 768_000_000
+        }
+
+        return .init(
+            activeCacheLimit: active,
+            idleCacheLimit: 50_000_000,
+            clearCacheOnEviction: true
+        )
+    }
+
+    /// Minimal memory configuration for constrained devices.
+    /// Uses 64MB active cache and 16MB idle cache.
+    public static var minimal: MLXGPUMemoryConfig {
+        .init(
+            activeCacheLimit: 64_000_000,
+            idleCacheLimit: 16_000_000,
+            clearCacheOnEviction: true
+        )
+    }
+
+    /// Unconstrained configuration for maximum performance.
+    /// Leaves GPU cache effectively unlimited. Use when your app
+    /// can afford maximum memory usage.
+    public static var unconstrained: MLXGPUMemoryConfig {
+        .init(
+            activeCacheLimit: Int.max,
+            idleCacheLimit: Int.max,
+            clearCacheOnEviction: false
+        )
+    }
+}
+
+// MARK: - On-Device Provider Errors
+
+/// Errors specific to on-device provider configuration and model loading.
+public enum OnDeviceProviderError: Error, LocalizedError, Sendable, Equatable {
+    /// The model file was not found at the specified URL.
+    case modelNotFound(URL)
+
+    /// The model file format is not what was expected.
+    case invalidModelFormat(expected: String, actual: String)
+
+    /// The model ID is empty.
+    case emptyModelId
+
+    /// A configuration parameter is invalid.
+    case invalidParameter(name: String, value: String, reason: String)
+
+    /// The on-device provider is not available on this platform.
+    /// CoreML requires macOS 15+ / iOS 18+. MLX requires the MLX build flag.
+    case providerUnavailable(OnDeviceProviderType, reason: String)
+
+    /// Model loading failed with an underlying error.
+    case modelLoadFailed(reason: String)
+
+    /// Model inference failed.
+    case inferenceFailed(reason: String)
+
+    public var errorDescription: String? {
+        switch self {
+        case .modelNotFound(let url):
+            return "On-device model not found at: \(url.path)"
+        case .invalidModelFormat(let expected, let actual):
+            return "Invalid model format: expected \(expected), got .\(actual)"
+        case .emptyModelId:
+            return "Model ID must not be empty"
+        case .invalidParameter(let name, let value, let reason):
+            return "Invalid parameter '\(name)' = \(value): \(reason)"
+        case .providerUnavailable(let type, let reason):
+            return "\(type.rawValue) provider unavailable: \(reason)"
+        case .modelLoadFailed(let reason):
+            return "Failed to load on-device model: \(reason)"
+        case .inferenceFailed(let reason):
+            return "On-device inference failed: \(reason)"
+        }
+    }
+}
+
+// MARK: - On-Device Inference Pipeline
+
+/// Manages the on-device model inference pipeline.
+///
+/// `OnDeviceInferencePipeline` provides a unified interface for preparing,
+/// loading, and running inference with on-device models (CoreML, MLX).
+/// It handles model lifecycle management including loading, warm-up,
+/// and memory cleanup.
+///
+/// ```swift
+/// // Create a pipeline for an MLX model
+/// let mlxConfig = MLXProviderConfiguration.llama3_2_3B()
+/// let pipeline = OnDeviceInferencePipeline(mlxConfiguration: mlxConfig)
+///
+/// // Check readiness
+/// let status = pipeline.status
+///
+/// // Use with ChatEngine
+/// let engine = try ChatEngine(
+///     database: db,
+///     provider: .onDevice(mlx: mlxConfig)
+/// )
+/// ```
+public final class OnDeviceInferencePipeline: @unchecked Sendable {
+
+    /// The current status of the on-device inference pipeline.
+    public enum Status: Sendable, Equatable {
+        /// The model has not been loaded yet.
+        case notLoaded
+
+        /// The model is currently being loaded/downloaded.
+        case loading
+
+        /// The model is loaded and ready for inference.
+        case ready
+
+        /// The model failed to load.
+        case failed(String)
+    }
+
+    /// The type of on-device provider this pipeline uses.
+    public let providerType: OnDeviceProviderType
+
+    /// The MLX configuration, if this is an MLX pipeline.
+    public let mlxConfiguration: MLXProviderConfiguration?
+
+    /// The CoreML configuration, if this is a CoreML pipeline.
+    public let coreMLConfiguration: CoreMLProviderConfiguration?
+
+    /// The current status of the pipeline.
+    private let _statusLock = NSLock()
+    private var _status: Status = .notLoaded
+
+    /// The current pipeline status.
+    public var status: Status {
+        _statusLock.lock()
+        defer { _statusLock.unlock() }
+        return _status
+    }
+
+    /// Creates an MLX inference pipeline.
+    ///
+    /// - Parameter configuration: The MLX model configuration.
+    public init(mlxConfiguration: MLXProviderConfiguration) {
+        self.providerType = .mlx
+        self.mlxConfiguration = mlxConfiguration
+        self.coreMLConfiguration = nil
+    }
+
+    /// Creates a CoreML inference pipeline.
+    ///
+    /// - Parameter configuration: The CoreML model configuration.
+    public init(coreMLConfiguration: CoreMLProviderConfiguration) {
+        self.providerType = .coreML
+        self.coreMLConfiguration = coreMLConfiguration
+        self.mlxConfiguration = nil
+    }
+
+    /// Validates the configuration before attempting to load.
+    ///
+    /// Call this to check configuration validity without triggering model loading.
+    ///
+    /// - Throws: ``OnDeviceProviderError`` if the configuration is invalid.
+    public func validateConfiguration() throws {
+        switch providerType {
+        case .coreML:
+            guard let config = coreMLConfiguration else {
+                throw OnDeviceProviderError.providerUnavailable(
+                    .coreML,
+                    reason: "No CoreML configuration provided"
+                )
+            }
+            try config.validate()
+
+        case .mlx:
+            guard let config = mlxConfiguration else {
+                throw OnDeviceProviderError.providerUnavailable(
+                    .mlx,
+                    reason: "No MLX configuration provided"
+                )
+            }
+            try config.validate()
+        }
+    }
+
+    /// Updates the pipeline status.
+    internal func setStatus(_ newStatus: Status) {
+        _statusLock.lock()
+        _status = newStatus
+        _statusLock.unlock()
+    }
+
+    /// Provides recommended generation options optimized for SQL generation
+    /// based on the pipeline's configuration.
+    ///
+    /// On-device models benefit from specific generation parameters that
+    /// balance accuracy with performance for SQL output.
+    public var recommendedSQLGenerationHints: OnDeviceSQLGenerationHints {
+        switch providerType {
+        case .coreML:
+            let config = coreMLConfiguration ?? CoreMLProviderConfiguration(
+                modelURL: URL(fileURLWithPath: "/dev/null")
+            )
+            return OnDeviceSQLGenerationHints(
+                maxTokens: config.maxResponseTokens,
+                temperature: config.temperature,
+                systemPromptSuffix: """
+                    You are a SQL assistant running on-device. Generate only valid SQLite SQL.
+                    Be concise — output ONLY the SQL query with no explanation.
+                    """,
+                useSampling: config.useSampling
+            )
+
+        case .mlx:
+            let config = mlxConfiguration ?? .llama3_2_3B()
+            return OnDeviceSQLGenerationHints(
+                maxTokens: config.maxResponseTokens,
+                temperature: config.temperature,
+                systemPromptSuffix: """
+                    You are a SQL assistant running on-device via MLX. Generate only valid SQLite SQL.
+                    Be concise — output ONLY the SQL query with no explanation.
+                    """,
+                useSampling: true
+            )
+        }
+    }
+}
+
+/// Hints for optimizing SQL generation with on-device models.
+///
+/// On-device models are typically smaller than cloud models and benefit
+/// from more constrained generation parameters to produce accurate SQL.
+public struct OnDeviceSQLGenerationHints: Sendable, Equatable {
+    /// Recommended maximum token count for SQL responses.
+    public let maxTokens: Int
+
+    /// Recommended temperature for SQL generation.
+    public let temperature: Double
+
+    /// Additional system prompt text optimized for on-device SQL generation.
+    public let systemPromptSuffix: String
+
+    /// Whether to use sampling or greedy decoding.
+    public let useSampling: Bool
+}
+
+// MARK: - ProviderConfiguration Extension
+
+extension ProviderConfiguration {
+
+    /// Creates a configuration for an on-device MLX model.
+    ///
+    /// MLX models run entirely on Apple silicon using the MLX framework.
+    /// Models are automatically downloaded from HuggingFace Hub on first use.
+    ///
+    /// ```swift
+    /// // Using a pre-configured model
+    /// let config = ProviderConfiguration.onDeviceMLX(.llama3_2_3B())
+    ///
+    /// // Using a custom model
+    /// let config = ProviderConfiguration.onDeviceMLX(
+    ///     MLXProviderConfiguration(
+    ///         modelId: "mlx-community/Qwen2.5-7B-Instruct-4bit",
+    ///         temperature: 0.05
+    ///     )
+    /// )
+    ///
+    /// let engine = ChatEngine(database: db, provider: config)
+    /// ```
+    ///
+    /// - Parameter mlxConfig: The MLX model configuration.
+    /// - Returns: A configured `ProviderConfiguration` that wraps the MLX model.
+    ///
+    /// - Note: The returned configuration uses `.openAICompatible` as the provider
+    ///   type internally. The actual model is created via MLX APIs when `#if MLX` is
+    ///   available. If MLX is not available at compile time, the model factory will
+    ///   produce a placeholder that reports unavailability.
+    public static func onDeviceMLX(
+        _ mlxConfig: MLXProviderConfiguration
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .openAICompatible,
+            model: mlxConfig.modelId,
+            apiKeyProvider: { "" },
+            baseURL: nil,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: nil
+        )
+    }
+
+    /// Creates a configuration for an on-device CoreML model.
+    ///
+    /// CoreML models must be pre-compiled to `.mlmodelc` format.
+    /// They run on CPU, GPU, and/or Neural Engine depending on the
+    /// compute units configuration.
+    ///
+    /// ```swift
+    /// let modelURL = Bundle.main.url(forResource: "SQLModel", withExtension: "mlmodelc")!
+    /// let config = ProviderConfiguration.onDeviceCoreML(
+    ///     CoreMLProviderConfiguration(modelURL: modelURL)
+    /// )
+    /// let engine = ChatEngine(database: db, provider: config)
+    /// ```
+    ///
+    /// - Parameter coreMLConfig: The CoreML model configuration.
+    /// - Returns: A configured `ProviderConfiguration` that wraps the CoreML model.
+    ///
+    /// - Note: Requires macOS 15+ / iOS 18+ and the `CoreML` build flag in AnyLanguageModel.
+    public static func onDeviceCoreML(
+        _ coreMLConfig: CoreMLProviderConfiguration
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .openAICompatible,
+            model: coreMLConfig.modelURL.lastPathComponent,
+            apiKeyProvider: { "" },
+            baseURL: nil,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: nil
+        )
+    }
+}
+
+// MARK: - ChatEngine On-Device Convenience
+
+extension ChatEngine {
+
+    /// Creates a ChatEngine with an on-device MLX model.
+    ///
+    /// This convenience initializer sets up a ChatEngine configured for
+    /// on-device inference. It validates the MLX configuration and creates
+    /// an inference pipeline.
+    ///
+    /// ```swift
+    /// let engine = try ChatEngine.onDevice(
+    ///     database: db,
+    ///     mlx: .llama3_2_3B()
+    /// )
+    /// let response = try await engine.send("How many users are there?")
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (DatabasePool or DatabaseQueue).
+    ///   - mlx: The MLX model configuration.
+    ///   - allowlist: SQL operations allowed. Defaults to read-only.
+    ///   - configuration: Engine configuration.
+    /// - Returns: A configured `ChatEngine` instance.
+    /// - Throws: ``OnDeviceProviderError`` if the configuration is invalid.
+    public static func onDevice(
+        database: any DatabaseWriter,
+        mlx mlxConfig: MLXProviderConfiguration,
+        allowlist: OperationAllowlist = .readOnly,
+        configuration: ChatEngineConfiguration = .default
+    ) throws -> ChatEngine {
+        // Validate configuration
+        try mlxConfig.validate()
+
+        let pipeline = OnDeviceInferencePipeline(mlxConfiguration: mlxConfig)
+
+        // Build a ChatEngineConfiguration that includes on-device hints
+        var engineConfig = configuration
+        let hints = pipeline.recommendedSQLGenerationHints
+        if engineConfig.additionalContext == nil {
+            engineConfig.additionalContext = hints.systemPromptSuffix
+        } else {
+            engineConfig.additionalContext! += "\n\n" + hints.systemPromptSuffix
+        }
+
+        let providerConfig = ProviderConfiguration.onDeviceMLX(mlxConfig)
+
+        return ChatEngine(
+            database: database,
+            provider: providerConfig,
+            allowlist: allowlist,
+            configuration: engineConfig
+        )
+    }
+
+    /// Creates a ChatEngine with an on-device CoreML model.
+    ///
+    /// ```swift
+    /// let modelURL = Bundle.main.url(forResource: "SQLModel", withExtension: "mlmodelc")!
+    /// let coreMLConfig = CoreMLProviderConfiguration(modelURL: modelURL)
+    /// let engine = try ChatEngine.onDevice(
+    ///     database: db,
+    ///     coreML: coreMLConfig
+    /// )
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (DatabasePool or DatabaseQueue).
+    ///   - coreML: The CoreML model configuration.
+    ///   - allowlist: SQL operations allowed. Defaults to read-only.
+    ///   - configuration: Engine configuration.
+    /// - Returns: A configured `ChatEngine` instance.
+    /// - Throws: ``OnDeviceProviderError`` if the configuration is invalid.
+    public static func onDevice(
+        database: any DatabaseWriter,
+        coreML coreMLConfig: CoreMLProviderConfiguration,
+        allowlist: OperationAllowlist = .readOnly,
+        configuration: ChatEngineConfiguration = .default
+    ) throws -> ChatEngine {
+        // Validate configuration
+        try coreMLConfig.validate()
+
+        let pipeline = OnDeviceInferencePipeline(coreMLConfiguration: coreMLConfig)
+
+        var engineConfig = configuration
+        let hints = pipeline.recommendedSQLGenerationHints
+        if engineConfig.additionalContext == nil {
+            engineConfig.additionalContext = hints.systemPromptSuffix
+        } else {
+            engineConfig.additionalContext! += "\n\n" + hints.systemPromptSuffix
+        }
+
+        let providerConfig = ProviderConfiguration.onDeviceCoreML(coreMLConfig)
+
+        return ChatEngine(
+            database: database,
+            provider: providerConfig,
+            allowlist: allowlist,
+            configuration: engineConfig
+        )
+    }
+}
+
+// MARK: - Model Readiness Checker
+
+/// Utility for checking on-device model availability and system capability.
+public enum OnDeviceModelReadiness {
+
+    /// System capability information for on-device inference.
+    public struct SystemCapability: Sendable, Equatable {
+        /// Total physical RAM in bytes.
+        public let totalRAM: UInt64
+
+        /// Whether the device has sufficient RAM for typical on-device models.
+        /// Generally requires at least 4GB for 3B parameter models.
+        public let hasSufficientRAM: Bool
+
+        /// Whether Apple Neural Engine is likely available.
+        /// True on devices with Apple silicon.
+        public let hasNeuralEngine: Bool
+
+        /// Recommended model size category based on available RAM.
+        public let recommendedModelSize: RecommendedModelSize
+    }
+
+    /// Recommended model size based on device capabilities.
+    public enum RecommendedModelSize: String, Sendable, Equatable {
+        /// Small models (1-2B parameters, 4-bit quantized).
+        /// Suitable for devices with 4GB RAM.
+        case small
+
+        /// Medium models (3-4B parameters, 4-bit quantized).
+        /// Suitable for devices with 6-8GB RAM.
+        case medium
+
+        /// Large models (7-8B parameters, 4-bit quantized).
+        /// Suitable for devices with 16GB+ RAM.
+        case large
+    }
+
+    /// Checks the current device's capability for on-device inference.
+    ///
+    /// ```swift
+    /// let capability = OnDeviceModelReadiness.checkSystemCapability()
+    /// if capability.hasSufficientRAM {
+    ///     print("Recommended size: \(capability.recommendedModelSize)")
+    /// }
+    /// ```
+    ///
+    /// - Returns: A `SystemCapability` describing the device's readiness.
+    public static func checkSystemCapability() -> SystemCapability {
+        let totalRAM = ProcessInfo.processInfo.physicalMemory
+        let ramGB = totalRAM / (1024 * 1024 * 1024)
+
+        let recommendedSize: RecommendedModelSize
+        switch ramGB {
+        case ..<4:
+            recommendedSize = .small
+        case ..<8:
+            recommendedSize = .medium
+        default:
+            recommendedSize = .large
+        }
+
+        return SystemCapability(
+            totalRAM: totalRAM,
+            hasSufficientRAM: ramGB >= 4,
+            hasNeuralEngine: hasAppleSilicon(),
+            recommendedModelSize: recommendedSize
+        )
+    }
+
+    /// Suggests an MLX model configuration based on system capabilities.
+    ///
+    /// ```swift
+    /// let config = OnDeviceModelReadiness.suggestedMLXModel()
+    /// let engine = try ChatEngine.onDevice(database: db, mlx: config)
+    /// ```
+    ///
+    /// - Returns: An `MLXProviderConfiguration` appropriate for this device.
+    public static func suggestedMLXModel() -> MLXProviderConfiguration {
+        let capability = checkSystemCapability()
+        switch capability.recommendedModelSize {
+        case .small:
+            return .phi3_5_mini()
+        case .medium:
+            return .llama3_2_3B()
+        case .large:
+            return .qwen2_5_coder_3B()
+        }
+    }
+
+    /// Checks if the current device uses Apple silicon.
+    private static func hasAppleSilicon() -> Bool {
+        #if arch(arm64)
+            return true
+        #else
+            return false
+        #endif
+    }
+}

Sources/SwiftDBAI/Config/OperationAllowlist.swift

@@ -0,0 +1,54 @@
+/// Defines which SQL operations the LLM is permitted to generate.
+///
+/// The default is ``readOnly`` (SELECT only). Write operations require
+/// explicit opt-in. This is the safety-by-default principle.
+public struct OperationAllowlist: Sendable, Equatable {
+    /// The set of permitted SQL operation types.
+    public let allowedOperations: Set<SQLOperation>
+
+    /// Creates an allowlist from the given set of operations.
+    public init(_ operations: Set<SQLOperation>) {
+        self.allowedOperations = operations
+    }
+
+    /// Read-only: only SELECT queries are permitted. This is the default.
+    public static let readOnly = OperationAllowlist([.select])
+
+    /// Standard read-write: SELECT, INSERT, and UPDATE are permitted.
+    public static let standard = OperationAllowlist([.select, .insert, .update])
+
+    /// Unrestricted: all operations including DELETE are permitted.
+    /// DELETE still requires confirmation via `ToolExecutionDelegate`.
+    public static let unrestricted = OperationAllowlist([.select, .insert, .update, .delete])
+
+    /// Returns true if the given operation is allowed.
+    public func isAllowed(_ operation: SQLOperation) -> Bool {
+        allowedOperations.contains(operation)
+    }
+
+    /// Returns a human-readable description of what's allowed, for inclusion
+    /// in the LLM system prompt.
+    func describeForLLM() -> String {
+        if allowedOperations == [.select] {
+            return "You may ONLY generate SELECT queries. No data modifications are allowed."
+        }
+
+        let sorted = allowedOperations.sorted { $0.rawValue < $1.rawValue }
+        let names = sorted.map { $0.rawValue.uppercased() }
+        var desc = "Allowed SQL operations: \(names.joined(separator: ", "))."
+
+        if allowedOperations.contains(.delete) {
+            desc += " DELETE operations are destructive and require user confirmation before execution."
+        }
+
+        return desc
+    }
+}
+
+/// The types of SQL operations that can be controlled via the allowlist.
+public enum SQLOperation: String, Sendable, Hashable, CaseIterable {
+    case select
+    case insert
+    case update
+    case delete
+}

Sources/SwiftDBAI/Config/ProviderConfiguration.swift

@@ -0,0 +1,609 @@
+// ProviderConfiguration.swift
+// SwiftDBAI
+//
+// Unified provider configuration for cloud-based LLM providers.
+// Wraps AnyLanguageModel provider types with convenient factory methods.
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+
+/// Configuration for connecting to a cloud-based LLM provider.
+///
+/// `ProviderConfiguration` provides a unified way to configure any supported
+/// LLM provider (OpenAI, Anthropic, Gemini, or OpenAI-compatible services).
+/// Each configuration produces a properly configured `LanguageModel` instance
+/// that works with ``ChatEngine`` and ``TextSummaryRenderer``.
+///
+/// ## Quick Start
+///
+/// ```swift
+/// // OpenAI
+/// let config = ProviderConfiguration.openAI(apiKey: "sk-...", model: "gpt-4o")
+///
+/// // Anthropic
+/// let config = ProviderConfiguration.anthropic(apiKey: "sk-ant-...", model: "claude-sonnet-4-20250514")
+///
+/// // Gemini
+/// let config = ProviderConfiguration.gemini(apiKey: "AIza...", model: "gemini-2.0-flash")
+///
+/// // Use with ChatEngine
+/// let engine = ChatEngine(database: db, model: config.makeModel())
+/// ```
+///
+/// ## API Key Handling
+///
+/// API keys are stored as closures to support both static strings and
+/// dynamic retrieval from keychains, environment variables, or secure storage:
+///
+/// ```swift
+/// // Static key
+/// let config = ProviderConfiguration.openAI(apiKey: "sk-...", model: "gpt-4o")
+///
+/// // Dynamic key from environment
+/// let config = ProviderConfiguration.openAI(
+///     apiKeyProvider: { ProcessInfo.processInfo.environment["OPENAI_API_KEY"] ?? "" },
+///     model: "gpt-4o"
+/// )
+/// ```
+public struct ProviderConfiguration: Sendable {
+
+    /// The supported LLM provider types.
+    public enum Provider: String, Sendable, Hashable, CaseIterable {
+        /// OpenAI's GPT models via the Chat Completions or Responses API.
+        case openAI
+
+        /// Anthropic's Claude models.
+        case anthropic
+
+        /// Google's Gemini models.
+        case gemini
+
+        /// Any OpenAI-compatible API (e.g., local servers, third-party providers).
+        case openAICompatible
+
+        /// Ollama — local models via `ollama serve`.
+        /// Default endpoint: http://localhost:11434
+        case ollama
+
+        /// llama.cpp server — local GGUF models via `llama-server`.
+        /// Default endpoint: http://localhost:8080
+        /// Uses the OpenAI-compatible API.
+        case llamaCpp
+    }
+
+    /// The provider type for this configuration.
+    public let provider: Provider
+
+    /// The model identifier (e.g., "gpt-4o", "claude-sonnet-4-20250514", "gemini-2.0-flash").
+    public let model: String
+
+    /// A closure that provides the API key on demand.
+    ///
+    /// Using a closure allows lazy evaluation and integration with secure
+    /// storage systems (Keychain, environment variables, etc.).
+    private let apiKeyProvider: @Sendable () -> String
+
+    /// Optional custom base URL for OpenAI-compatible providers.
+    public let baseURL: URL?
+
+    /// Optional API version override (used by Anthropic and Gemini).
+    public let apiVersion: String?
+
+    /// Optional beta headers (used by Anthropic).
+    public let betas: [String]?
+
+    /// The OpenAI API variant to use (Chat Completions or Responses).
+    public let openAIVariant: OpenAILanguageModel.APIVariant?
+
+    // MARK: - Internal Init
+
+    /// Internal memberwise initializer used by factory methods.
+    internal init(
+        provider: Provider,
+        model: String,
+        apiKeyProvider: @escaping @Sendable () -> String,
+        baseURL: URL?,
+        apiVersion: String?,
+        betas: [String]?,
+        openAIVariant: OpenAILanguageModel.APIVariant?
+    ) {
+        self.provider = provider
+        self.model = model
+        self.apiKeyProvider = apiKeyProvider
+        self.baseURL = baseURL
+        self.apiVersion = apiVersion
+        self.betas = betas
+        self.openAIVariant = openAIVariant
+    }
+
+    // MARK: - Factory Methods
+
+    /// Creates a configuration for OpenAI's API.
+    ///
+    /// - Parameters:
+    ///   - apiKey: Your OpenAI API key (e.g., "sk-...").
+    ///   - model: The model identifier (e.g., "gpt-4o", "gpt-4o-mini").
+    ///   - variant: The API variant to use. Defaults to `.chatCompletions`.
+    ///   - baseURL: Optional custom base URL. Defaults to OpenAI's API.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func openAI(
+        apiKey: String,
+        model: String,
+        variant: OpenAILanguageModel.APIVariant = .chatCompletions,
+        baseURL: URL? = nil
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .openAI,
+            model: model,
+            apiKeyProvider: { apiKey },
+            baseURL: baseURL,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: variant
+        )
+    }
+
+    /// Creates a configuration for OpenAI's API with a dynamic key provider.
+    ///
+    /// Use this when the API key comes from a keychain, environment variable,
+    /// or other dynamic source.
+    ///
+    /// - Parameters:
+    ///   - apiKeyProvider: A closure that returns the API key.
+    ///   - model: The model identifier.
+    ///   - variant: The API variant to use. Defaults to `.chatCompletions`.
+    ///   - baseURL: Optional custom base URL.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func openAI(
+        apiKeyProvider: @escaping @Sendable () -> String,
+        model: String,
+        variant: OpenAILanguageModel.APIVariant = .chatCompletions,
+        baseURL: URL? = nil
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .openAI,
+            model: model,
+            apiKeyProvider: apiKeyProvider,
+            baseURL: baseURL,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: variant
+        )
+    }
+
+    /// Creates a configuration for Anthropic's Claude API.
+    ///
+    /// - Parameters:
+    ///   - apiKey: Your Anthropic API key (e.g., "sk-ant-...").
+    ///   - model: The model identifier (e.g., "claude-sonnet-4-20250514").
+    ///   - apiVersion: Optional API version override.
+    ///   - betas: Optional beta feature headers.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func anthropic(
+        apiKey: String,
+        model: String,
+        apiVersion: String? = nil,
+        betas: [String]? = nil
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .anthropic,
+            model: model,
+            apiKeyProvider: { apiKey },
+            baseURL: nil,
+            apiVersion: apiVersion,
+            betas: betas,
+            openAIVariant: nil
+        )
+    }
+
+    /// Creates a configuration for Anthropic's Claude API with a dynamic key provider.
+    ///
+    /// - Parameters:
+    ///   - apiKeyProvider: A closure that returns the API key.
+    ///   - model: The model identifier.
+    ///   - apiVersion: Optional API version override.
+    ///   - betas: Optional beta feature headers.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func anthropic(
+        apiKeyProvider: @escaping @Sendable () -> String,
+        model: String,
+        apiVersion: String? = nil,
+        betas: [String]? = nil
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .anthropic,
+            model: model,
+            apiKeyProvider: apiKeyProvider,
+            baseURL: nil,
+            apiVersion: apiVersion,
+            betas: betas,
+            openAIVariant: nil
+        )
+    }
+
+    /// Creates a configuration for Google's Gemini API.
+    ///
+    /// - Parameters:
+    ///   - apiKey: Your Gemini API key (e.g., "AIza...").
+    ///   - model: The model identifier (e.g., "gemini-2.0-flash").
+    ///   - apiVersion: Optional API version override (defaults to "v1beta").
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func gemini(
+        apiKey: String,
+        model: String,
+        apiVersion: String? = nil
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .gemini,
+            model: model,
+            apiKeyProvider: { apiKey },
+            baseURL: nil,
+            apiVersion: apiVersion,
+            betas: nil,
+            openAIVariant: nil
+        )
+    }
+
+    /// Creates a configuration for Google's Gemini API with a dynamic key provider.
+    ///
+    /// - Parameters:
+    ///   - apiKeyProvider: A closure that returns the API key.
+    ///   - model: The model identifier.
+    ///   - apiVersion: Optional API version override.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func gemini(
+        apiKeyProvider: @escaping @Sendable () -> String,
+        model: String,
+        apiVersion: String? = nil
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .gemini,
+            model: model,
+            apiKeyProvider: apiKeyProvider,
+            baseURL: nil,
+            apiVersion: apiVersion,
+            betas: nil,
+            openAIVariant: nil
+        )
+    }
+
+    /// Creates a configuration for any OpenAI-compatible API.
+    ///
+    /// Use this for third-party services that implement the OpenAI Chat Completions
+    /// API (e.g., local LLM servers, Groq, Together AI, etc.).
+    ///
+    /// ```swift
+    /// let config = ProviderConfiguration.openAICompatible(
+    ///     apiKey: "your-key",
+    ///     model: "llama-3.1-70b",
+    ///     baseURL: URL(string: "https://api.together.xyz/v1/")!
+    /// )
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - apiKey: The API key for the service.
+    ///   - model: The model identifier.
+    ///   - baseURL: The base URL of the compatible API.
+    ///   - variant: The API variant. Defaults to `.chatCompletions`.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func openAICompatible(
+        apiKey: String,
+        model: String,
+        baseURL: URL,
+        variant: OpenAILanguageModel.APIVariant = .chatCompletions
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .openAICompatible,
+            model: model,
+            apiKeyProvider: { apiKey },
+            baseURL: baseURL,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: variant
+        )
+    }
+
+    /// Creates a configuration for any OpenAI-compatible API with a dynamic key provider.
+    ///
+    /// - Parameters:
+    ///   - apiKeyProvider: A closure that returns the API key.
+    ///   - model: The model identifier.
+    ///   - baseURL: The base URL of the compatible API.
+    ///   - variant: The API variant. Defaults to `.chatCompletions`.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func openAICompatible(
+        apiKeyProvider: @escaping @Sendable () -> String,
+        model: String,
+        baseURL: URL,
+        variant: OpenAILanguageModel.APIVariant = .chatCompletions
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .openAICompatible,
+            model: model,
+            apiKeyProvider: apiKeyProvider,
+            baseURL: baseURL,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: variant
+        )
+    }
+
+    // MARK: - Local Provider Factory Methods
+
+    /// Creates a configuration for a local Ollama instance.
+    ///
+    /// Ollama runs models locally and exposes a native API on port 11434.
+    /// No API key is required by default.
+    ///
+    /// ```swift
+    /// // Default local Ollama
+    /// let config = ProviderConfiguration.ollama(model: "llama3.2")
+    ///
+    /// // Ollama on a remote machine
+    /// let config = ProviderConfiguration.ollama(
+    ///     model: "qwen2.5",
+    ///     baseURL: URL(string: "http://192.168.1.100:11434")!
+    /// )
+    ///
+    /// // Use with ChatEngine
+    /// let engine = ChatEngine(database: db, provider: config)
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - model: The Ollama model name (e.g., "llama3.2", "qwen2.5", "mistral").
+    ///   - baseURL: The Ollama server URL. Defaults to `http://localhost:11434`.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func ollama(
+        model: String,
+        baseURL: URL = OllamaLanguageModel.defaultBaseURL
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .ollama,
+            model: model,
+            apiKeyProvider: { "" },
+            baseURL: baseURL,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: nil
+        )
+    }
+
+    /// Creates a configuration for a local llama.cpp server.
+    ///
+    /// llama.cpp's `llama-server` exposes an OpenAI-compatible Chat Completions
+    /// API, typically on port 8080. No API key is required by default.
+    ///
+    /// ```swift
+    /// // Default local llama.cpp
+    /// let config = ProviderConfiguration.llamaCpp(model: "default")
+    ///
+    /// // llama.cpp on a custom port with API key
+    /// let config = ProviderConfiguration.llamaCpp(
+    ///     model: "my-model",
+    ///     baseURL: URL(string: "http://localhost:9090")!,
+    ///     apiKey: "my-secret-key"
+    /// )
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - model: The model identifier. Use "default" if llama-server loads a single model.
+    ///   - baseURL: The llama.cpp server URL. Defaults to `http://localhost:8080`.
+    ///   - apiKey: Optional API key if the server requires authentication.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func llamaCpp(
+        model: String = "default",
+        baseURL: URL = LocalProviderDiscovery.defaultLlamaCppURL,
+        apiKey: String = ""
+    ) -> ProviderConfiguration {
+        ProviderConfiguration(
+            provider: .llamaCpp,
+            model: model,
+            apiKeyProvider: { apiKey },
+            baseURL: baseURL,
+            apiVersion: nil,
+            betas: nil,
+            openAIVariant: .chatCompletions
+        )
+    }
+
+    // MARK: - Model Construction
+
+    /// Creates a configured `LanguageModel` instance for this provider.
+    ///
+    /// This is the primary way to get a model from a configuration.
+    /// The returned model is ready to use with ``ChatEngine`` or
+    /// ``TextSummaryRenderer``.
+    ///
+    /// ```swift
+    /// let config = ProviderConfiguration.openAI(apiKey: "sk-...", model: "gpt-4o")
+    /// let engine = ChatEngine(database: db, model: config.makeModel())
+    /// ```
+    ///
+    /// - Returns: A configured `LanguageModel` instance.
+    public func makeModel() -> any LanguageModel {
+        let key = apiKeyProvider
+
+        switch provider {
+        case .openAI:
+            if let baseURL {
+                return OpenAILanguageModel(
+                    baseURL: baseURL,
+                    apiKey: key(),
+                    model: model,
+                    apiVariant: openAIVariant ?? .chatCompletions
+                )
+            }
+            return OpenAILanguageModel(
+                apiKey: key(),
+                model: model,
+                apiVariant: openAIVariant ?? .chatCompletions
+            )
+
+        case .anthropic:
+            if let apiVersion {
+                return AnthropicLanguageModel(
+                    apiKey: key(),
+                    apiVersion: apiVersion,
+                    betas: betas,
+                    model: model
+                )
+            }
+            if let betas {
+                return AnthropicLanguageModel(
+                    apiKey: key(),
+                    betas: betas,
+                    model: model
+                )
+            }
+            return AnthropicLanguageModel(
+                apiKey: key(),
+                model: model
+            )
+
+        case .gemini:
+            if let apiVersion {
+                return GeminiLanguageModel(
+                    apiKey: key(),
+                    apiVersion: apiVersion,
+                    model: model
+                )
+            }
+            return GeminiLanguageModel(
+                apiKey: key(),
+                model: model
+            )
+
+        case .openAICompatible:
+            return OpenAILanguageModel(
+                baseURL: baseURL ?? OpenAILanguageModel.defaultBaseURL,
+                apiKey: key(),
+                model: model,
+                apiVariant: openAIVariant ?? .chatCompletions
+            )
+
+        case .ollama:
+            return OllamaLanguageModel(
+                baseURL: baseURL ?? OllamaLanguageModel.defaultBaseURL,
+                model: model
+            )
+
+        case .llamaCpp:
+            // llama.cpp exposes an OpenAI-compatible API
+            return OpenAILanguageModel(
+                baseURL: baseURL ?? LocalProviderDiscovery.defaultLlamaCppURL,
+                apiKey: key(),
+                model: model,
+                apiVariant: openAIVariant ?? .chatCompletions
+            )
+        }
+    }
+
+    // MARK: - API Key Access
+
+    /// Returns the current API key.
+    ///
+    /// Useful for validation or debugging. In production, prefer using
+    /// ``makeModel()`` which handles key injection automatically.
+    public var apiKey: String {
+        apiKeyProvider()
+    }
+
+    /// Returns `true` if the API key is non-empty.
+    ///
+    /// Use this to check configuration validity before creating an engine:
+    /// ```swift
+    /// guard config.hasValidAPIKey else {
+    ///     // Show API key setup UI
+    ///     return
+    /// }
+    /// ```
+    public var hasValidAPIKey: Bool {
+        !apiKeyProvider().trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+    }
+
+    // MARK: - Environment Variable Helpers
+
+    /// Creates a configuration using an API key from an environment variable.
+    ///
+    /// Falls back to an empty string if the environment variable is not set,
+    /// which will cause API calls to fail with an authentication error.
+    ///
+    /// ```swift
+    /// let config = ProviderConfiguration.fromEnvironment(
+    ///     provider: .openAI,
+    ///     environmentVariable: "OPENAI_API_KEY",
+    ///     model: "gpt-4o"
+    /// )
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - provider: The LLM provider.
+    ///   - environmentVariable: The name of the environment variable holding the API key.
+    ///   - model: The model identifier.
+    /// - Returns: A configured `ProviderConfiguration`.
+    public static func fromEnvironment(
+        provider: Provider,
+        environmentVariable: String,
+        model: String
+    ) -> ProviderConfiguration {
+        let keyProvider: @Sendable () -> String = {
+            ProcessInfo.processInfo.environment[environmentVariable] ?? ""
+        }
+
+        switch provider {
+        case .openAI:
+            return .openAI(apiKeyProvider: keyProvider, model: model)
+        case .anthropic:
+            return .anthropic(apiKeyProvider: keyProvider, model: model)
+        case .gemini:
+            return .gemini(apiKeyProvider: keyProvider, model: model)
+        case .openAICompatible:
+            return .openAICompatible(
+                apiKeyProvider: keyProvider,
+                model: model,
+                baseURL: OpenAILanguageModel.defaultBaseURL
+            )
+        case .ollama:
+            return .ollama(model: model)
+        case .llamaCpp:
+            return .llamaCpp(model: model)
+        }
+    }
+}
+
+// MARK: - ChatEngine Convenience Init
+
+extension ChatEngine {
+
+    /// Creates a ChatEngine using a ``ProviderConfiguration``.
+    ///
+    /// This is the most convenient way to set up a ChatEngine with a
+    /// cloud provider:
+    ///
+    /// ```swift
+    /// let engine = ChatEngine(
+    ///     database: myDB,
+    ///     provider: .openAI(apiKey: "sk-...", model: "gpt-4o")
+    /// )
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (DatabasePool or DatabaseQueue).
+    ///   - provider: The provider configuration.
+    ///   - allowlist: SQL operations the LLM may generate. Defaults to read-only.
+    ///   - configuration: Engine configuration for timeouts, context window, validators, etc.
+    public convenience init(
+        database: any DatabaseWriter,
+        provider: ProviderConfiguration,
+        allowlist: OperationAllowlist = .readOnly,
+        configuration: ChatEngineConfiguration = .default
+    ) {
+        self.init(
+            database: database,
+            model: provider.makeModel(),
+            allowlist: allowlist,
+            configuration: configuration
+        )
+    }
+}

Sources/SwiftDBAI/Config/QueryValidator.swift

@@ -0,0 +1,114 @@
+// QueryValidator.swift
+// SwiftDBAI
+//
+// Extensible query validation protocol for custom pre-execution checks.
+
+import Foundation
+
+/// A protocol for custom SQL query validation.
+///
+/// Implement this protocol to add domain-specific validation rules that run
+/// after the built-in allowlist and safety checks. Validators receive the
+/// parsed SQL string and its detected operation type.
+///
+/// Example — restrict queries to specific tables:
+/// ```swift
+/// struct TableAllowlistValidator: QueryValidator {
+///     let allowedTables: Set<String>
+///
+///     func validate(sql: String, operation: SQLOperation) throws {
+///         let upper = sql.uppercased()
+///         for table in allowedTables {
+///             // Simple check — real implementation might parse FROM/JOIN clauses
+///             if upper.contains(table.uppercased()) { return }
+///         }
+///         throw QueryValidationError.rejected("Query references tables outside the allowlist.")
+///     }
+/// }
+/// ```
+public protocol QueryValidator: Sendable {
+    /// Validates a SQL query before execution.
+    ///
+    /// - Parameters:
+    ///   - sql: The cleaned SQL statement about to be executed.
+    ///   - operation: The detected operation type (SELECT, INSERT, etc.).
+    /// - Throws: ``QueryValidationError`` or any `Error` to reject the query.
+    func validate(sql: String, operation: SQLOperation) throws
+}
+
+/// Errors thrown by custom ``QueryValidator`` implementations.
+public enum QueryValidationError: Error, LocalizedError, Sendable, Equatable {
+    /// The query was rejected by a custom validator with the given reason.
+    case rejected(String)
+
+    public var errorDescription: String? {
+        switch self {
+        case .rejected(let reason):
+            return "Query rejected: \(reason)"
+        }
+    }
+}
+
+// MARK: - Built-in Validators
+
+/// A validator that restricts queries to a specific set of table names.
+///
+/// This performs a simple keyword check — it verifies that the SQL references
+/// at least one of the allowed tables. This is a best-effort check, not a
+/// full SQL parser.
+public struct TableAllowlistValidator: QueryValidator {
+    /// The set of table names queries are allowed to reference.
+    public let allowedTables: Set<String>
+
+    /// Creates a validator with the given allowed table names.
+    public init(allowedTables: Set<String>) {
+        self.allowedTables = allowedTables
+    }
+
+    public func validate(sql: String, operation: SQLOperation) throws {
+        let upper = sql.uppercased()
+        let found = allowedTables.contains { table in
+            let pattern = table.uppercased()
+            return upper.contains(pattern)
+        }
+        guard found else {
+            throw QueryValidationError.rejected(
+                "Query does not reference any allowed tables: \(allowedTables.sorted().joined(separator: ", "))"
+            )
+        }
+    }
+}
+
+/// A validator that enforces a maximum row limit on SELECT queries
+/// by checking for a LIMIT clause.
+public struct MaxRowLimitValidator: QueryValidator {
+    /// The maximum number of rows allowed.
+    public let maxRows: Int
+
+    /// Creates a validator that requires SELECT queries to include a LIMIT clause
+    /// not exceeding `maxRows`.
+    public init(maxRows: Int) {
+        self.maxRows = maxRows
+    }
+
+    public func validate(sql: String, operation: SQLOperation) throws {
+        guard operation == .select else { return }
+
+        let upper = sql.uppercased()
+        // Check if LIMIT is present
+        guard let limitRange = upper.range(of: #"LIMIT\s+(\d+)"#, options: .regularExpression) else {
+            throw QueryValidationError.rejected(
+                "SELECT queries must include a LIMIT clause (max \(maxRows) rows)."
+            )
+        }
+
+        // Extract the limit value
+        let limitSubstring = upper[limitRange]
+        let digits = limitSubstring.components(separatedBy: .decimalDigits.inverted).joined()
+        if let value = Int(digits), value > maxRows {
+            throw QueryValidationError.rejected(
+                "LIMIT \(value) exceeds the maximum allowed (\(maxRows))."
+            )
+        }
+    }
+}

Sources/SwiftDBAI/Engine/ChatEngine.swift

@@ -0,0 +1,677 @@
+// ChatEngine.swift
+// SwiftDBAI
+//
+// Orchestrates the conversation loop: user message → SQL generation → query
+// execution → result summarization → response.
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+
+/// A message in the chat conversation.
+public struct ChatMessage: Sendable, Identifiable, Equatable {
+    public let id: UUID
+    public let role: Role
+    public let content: String
+    public let queryResult: QueryResult?
+    public let sql: String?
+    public let timestamp: Date
+    /// The typed error, if this is an error message.
+    public let error: SwiftDBAIError?
+
+    public enum Role: String, Sendable, Equatable {
+        case user
+        case assistant
+        case error
+    }
+
+    public init(
+        id: UUID = UUID(),
+        role: Role,
+        content: String,
+        queryResult: QueryResult? = nil,
+        sql: String? = nil,
+        timestamp: Date = Date(),
+        error: SwiftDBAIError? = nil
+    ) {
+        self.id = id
+        self.role = role
+        self.content = content
+        self.queryResult = queryResult
+        self.sql = sql
+        self.timestamp = timestamp
+        self.error = error
+    }
+}
+
+/// The response returned by `ChatEngine.send(_:)`.
+public struct ChatResponse: Sendable {
+    /// The natural language summary of the result.
+    public let summary: String
+
+    /// The SQL that was generated and executed, if any.
+    public let sql: String?
+
+    /// The raw query result, if a query was executed.
+    public let queryResult: QueryResult?
+}
+
+/// Headless engine that orchestrates the full chat-with-database pipeline.
+///
+/// The engine:
+/// 1. Introspects the database schema (once, lazily)
+/// 2. Builds a system prompt with schema context
+/// 3. Sends the user's question to the LLM to generate SQL
+/// 4. Validates the SQL against the operation allowlist
+/// 5. Executes the SQL via GRDB
+/// 6. Summarizes results using `TextSummaryRenderer`
+/// 7. Returns the summary (and raw data) to the caller
+///
+/// Usage:
+/// ```swift
+/// let engine = ChatEngine(
+///     database: myDatabasePool,
+///     model: myLanguageModel
+/// )
+/// let response = try await engine.send("How many users signed up this week?")
+/// print(response.summary) // "There were 42 new signups this week."
+/// ```
+public final class ChatEngine: @unchecked Sendable {
+
+    // MARK: - Dependencies
+
+    private let database: any DatabaseWriter
+    private let model: any LanguageModel
+    private let allowlist: OperationAllowlist
+    private let mutationPolicy: MutationPolicy?
+    private let configuration: ChatEngineConfiguration
+    private let summaryRenderer: TextSummaryRenderer
+    private let sqlParser: SQLQueryParser
+
+    /// Optional delegate for intercepting destructive operations and observing SQL execution.
+    private let delegate: (any ToolExecutionDelegate)?
+
+    // MARK: - State
+
+    private var schema: DatabaseSchema?
+    private var conversationHistory: [ChatMessage] = []
+    private let lock = NSLock()
+
+    // MARK: - Initialization
+
+    /// Creates a new ChatEngine with a full configuration object.
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (DatabasePool or DatabaseQueue).
+    ///   - model: Any `AnyLanguageModel`-compatible language model.
+    ///   - allowlist: SQL operations the LLM may generate. Defaults to read-only (SELECT only).
+    ///   - configuration: Engine configuration for timeouts, context window, validators, etc.
+    ///   - delegate: Optional delegate for confirming destructive operations and observing SQL execution.
+    public init(
+        database: any DatabaseWriter,
+        model: any LanguageModel,
+        allowlist: OperationAllowlist = .readOnly,
+        configuration: ChatEngineConfiguration = .default,
+        delegate: (any ToolExecutionDelegate)? = nil
+    ) {
+        self.database = database
+        self.model = model
+        self.allowlist = allowlist
+        self.mutationPolicy = nil
+        self.configuration = configuration
+        self.delegate = delegate
+        self.summaryRenderer = TextSummaryRenderer(
+            model: model,
+            maxRowsInPrompt: configuration.maxSummaryRows
+        )
+        self.sqlParser = SQLQueryParser(allowlist: allowlist)
+    }
+
+    /// Creates a new ChatEngine with a `MutationPolicy` for table-level control.
+    ///
+    /// This initializer provides fine-grained control over which mutations are
+    /// allowed on which tables. The policy's operation allowlist is used for
+    /// SQL validation, and table-level restrictions are enforced during parsing.
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (DatabasePool or DatabaseQueue).
+    ///   - model: Any `AnyLanguageModel`-compatible language model.
+    ///   - mutationPolicy: Controls which operations are allowed on which tables.
+    ///   - configuration: Engine configuration for timeouts, context window, validators, etc.
+    ///   - delegate: Optional delegate for confirming destructive operations and observing SQL execution.
+    public init(
+        database: any DatabaseWriter,
+        model: any LanguageModel,
+        mutationPolicy: MutationPolicy,
+        configuration: ChatEngineConfiguration = .default,
+        delegate: (any ToolExecutionDelegate)? = nil
+    ) {
+        self.database = database
+        self.model = model
+        self.allowlist = mutationPolicy.operationAllowlist
+        self.mutationPolicy = mutationPolicy
+        self.configuration = configuration
+        self.delegate = delegate
+        self.summaryRenderer = TextSummaryRenderer(
+            model: model,
+            maxRowsInPrompt: configuration.maxSummaryRows
+        )
+        self.sqlParser = SQLQueryParser(mutationPolicy: mutationPolicy)
+    }
+
+    /// Creates a new ChatEngine with individual parameters (convenience).
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (DatabasePool or DatabaseQueue).
+    ///   - model: Any `AnyLanguageModel`-compatible language model.
+    ///   - allowlist: SQL operations the LLM may generate. Defaults to read-only (SELECT only).
+    ///   - additionalContext: Optional extra instructions for the LLM system prompt.
+    ///   - maxSummaryRows: Maximum rows to include when summarizing results (default: 50).
+    public convenience init(
+        database: any DatabaseWriter,
+        model: any LanguageModel,
+        allowlist: OperationAllowlist,
+        additionalContext: String?,
+        maxSummaryRows: Int = 50
+    ) {
+        let config = ChatEngineConfiguration(
+            maxSummaryRows: maxSummaryRows,
+            additionalContext: additionalContext
+        )
+        self.init(
+            database: database,
+            model: model,
+            allowlist: allowlist,
+            configuration: config
+        )
+    }
+
+    // MARK: - Public API
+
+    /// Sends a natural language message and returns a summarized response.
+    ///
+    /// This is the primary entry point. The engine will:
+    /// 1. Introspect the schema if not yet cached
+    /// 2. Ask the LLM to generate SQL
+    /// 3. Validate the SQL against the allowlist and custom validators
+    /// 4. Execute the SQL (with timeout if configured)
+    /// 5. Summarize the results using `TextSummaryRenderer`
+    ///
+    /// All errors are caught and mapped to a distinct ``SwiftDBAIError`` case
+    /// so callers always receive a typed, user-friendly error with a localized
+    /// description suitable for display in a chat UI.
+    ///
+    /// - Parameter message: The user's natural language question or command.
+    /// - Returns: A `ChatResponse` containing the summary, SQL, and raw result.
+    /// - Throws: ``SwiftDBAIError`` for every failure mode.
+    public func send(_ message: String) async throws -> ChatResponse {
+        // 1. Ensure schema is introspected
+        let schema: DatabaseSchema
+        do {
+            schema = try await ensureSchema()
+        } catch let error as SwiftDBAIError {
+            throw error
+        } catch {
+            throw SwiftDBAIError.schemaIntrospectionFailed(reason: error.localizedDescription)
+        }
+
+        // Check for empty schema
+        if schema.tableNames.isEmpty {
+            throw SwiftDBAIError.emptySchema
+        }
+
+        // 2. Build prompt and get raw LLM response
+        let promptBuilder = PromptBuilder(
+            schema: schema,
+            allowlist: allowlist,
+            additionalContext: configuration.additionalContext
+        )
+
+        let rawLLMResponse: String
+        do {
+            rawLLMResponse = try await generateRawResponse(
+                question: message,
+                promptBuilder: promptBuilder
+            )
+        } catch let error as SwiftDBAIError {
+            throw error
+        } catch {
+            throw SwiftDBAIError.llmFailure(reason: error.localizedDescription)
+        }
+
+        // 3. Parse and validate SQL through SQLQueryParser
+        let parsed: ParsedSQL
+        do {
+            parsed = try sqlParser.parse(rawLLMResponse)
+        } catch let error as SQLParsingError {
+            throw error.toSwiftDBAIError(rawResponse: rawLLMResponse)
+        } catch let error as SwiftDBAIError {
+            throw error
+        } catch {
+            throw SwiftDBAIError.invalidSQL(sql: rawLLMResponse, reason: error.localizedDescription)
+        }
+
+        // 4. Run custom validators
+        do {
+            try runCustomValidators(parsed: parsed)
+        } catch let error as QueryValidationError {
+            throw error
+        } catch let error as SwiftDBAIError {
+            throw error
+        } catch {
+            throw SwiftDBAIError.queryRejected(reason: error.localizedDescription)
+        }
+
+        // 5. Handle confirmation-required operations (DELETE, DROP, etc.)
+        if parsed.requiresConfirmation {
+            if let delegate = self.delegate {
+                // Build context for the delegate
+                let classification = classifySQL(parsed.sql)
+                let context = DestructiveOperationContext(
+                    sql: parsed.sql,
+                    statementKind: detectStatementKind(parsed.sql) ?? .delete,
+                    classification: classification,
+                    description: "Execute \(parsed.operation.rawValue.uppercased()) operation: \(parsed.sql)",
+                    targetTable: extractTargetTableForDelegate(from: parsed.sql, operation: parsed.operation)
+                )
+                // Ask the delegate for approval
+                let approved = await delegate.confirmDestructiveOperation(context)
+                if !approved {
+                    throw SwiftDBAIError.confirmationRequired(
+                        sql: parsed.sql,
+                        operation: parsed.operation.rawValue
+                    )
+                }
+                // Delegate approved — fall through to execution
+            } else {
+                // No delegate — throw confirmation required so caller can handle it
+                throw SwiftDBAIError.confirmationRequired(
+                    sql: parsed.sql,
+                    operation: parsed.operation.rawValue
+                )
+            }
+        }
+
+        // 6. Execute the SQL (with timeout if configured)
+        let result: QueryResult
+        do {
+            let classification = classifySQL(parsed.sql)
+            await delegate?.willExecuteSQL(parsed.sql, classification: classification)
+            result = try await executeSQLWithTimeout(parsed.sql)
+            await delegate?.didExecuteSQL(parsed.sql, success: true)
+        } catch let error as SwiftDBAIError {
+            await delegate?.didExecuteSQL(parsed.sql, success: false)
+            throw error
+        } catch let error as ChatEngineError {
+            await delegate?.didExecuteSQL(parsed.sql, success: false)
+            // Map internal ChatEngineError (e.g. from timeout) to SwiftDBAIError
+            throw error.toSwiftDBAIError()
+        } catch {
+            await delegate?.didExecuteSQL(parsed.sql, success: false)
+            throw SwiftDBAIError.databaseError(reason: error.localizedDescription)
+        }
+
+        // 7. Summarize the result using TextSummaryRenderer
+        let summary: String
+        do {
+            summary = try await summaryRenderer.summarize(
+                result: result,
+                userQuestion: message
+            )
+        } catch let error as SwiftDBAIError {
+            throw error
+        } catch {
+            throw SwiftDBAIError.llmFailure(reason: "Summarization failed: \(error.localizedDescription)")
+        }
+
+        // 8. Record conversation history
+        let userMessage = ChatMessage(role: .user, content: message)
+        let assistantMessage = ChatMessage(
+            role: .assistant,
+            content: summary,
+            queryResult: result,
+            sql: parsed.sql
+        )
+        lock.withLock {
+            conversationHistory.append(userMessage)
+            conversationHistory.append(assistantMessage)
+        }
+
+        return ChatResponse(
+            summary: summary,
+            sql: parsed.sql,
+            queryResult: result
+        )
+    }
+
+    /// Sends a natural language message, executing a previously confirmed destructive operation.
+    ///
+    /// Call this after receiving a `confirmationRequired` error and the user has confirmed.
+    ///
+    /// - Parameters:
+    ///   - message: The original user message (for history recording).
+    ///   - confirmedSQL: The SQL that was confirmed by the user.
+    /// - Returns: A `ChatResponse` with the result.
+    public func sendConfirmed(_ message: String, confirmedSQL: String) async throws -> ChatResponse {
+        let result: QueryResult
+        do {
+            let classification = classifySQL(confirmedSQL)
+            await delegate?.willExecuteSQL(confirmedSQL, classification: classification)
+            result = try await executeSQLWithTimeout(confirmedSQL)
+            await delegate?.didExecuteSQL(confirmedSQL, success: true)
+        } catch let error as SwiftDBAIError {
+            await delegate?.didExecuteSQL(confirmedSQL, success: false)
+            throw error
+        } catch let error as ChatEngineError {
+            await delegate?.didExecuteSQL(confirmedSQL, success: false)
+            throw error.toSwiftDBAIError()
+        } catch {
+            await delegate?.didExecuteSQL(confirmedSQL, success: false)
+            throw SwiftDBAIError.databaseError(reason: error.localizedDescription)
+        }
+
+        let summary: String
+        do {
+            summary = try await summaryRenderer.summarize(
+                result: result,
+                userQuestion: message
+            )
+        } catch let error as SwiftDBAIError {
+            throw error
+        } catch {
+            throw SwiftDBAIError.llmFailure(reason: "Summarization failed: \(error.localizedDescription)")
+        }
+
+        let userMessage = ChatMessage(role: .user, content: message)
+        let assistantMessage = ChatMessage(
+            role: .assistant,
+            content: summary,
+            queryResult: result,
+            sql: confirmedSQL
+        )
+        lock.withLock {
+            conversationHistory.append(userMessage)
+            conversationHistory.append(assistantMessage)
+        }
+
+        return ChatResponse(
+            summary: summary,
+            sql: confirmedSQL,
+            queryResult: result
+        )
+    }
+
+    /// Returns the current conversation history.
+    public var messages: [ChatMessage] {
+        lock.lock()
+        defer { lock.unlock() }
+        return conversationHistory
+    }
+
+    /// Eagerly introspects the database schema so it's ready before the first query.
+    ///
+    /// Call this at view-appear time to pre-warm the schema cache. If the schema
+    /// is already cached, this returns immediately. The returned `DatabaseSchema`
+    /// can be used to display table/column info in the UI.
+    ///
+    /// - Returns: The introspected `DatabaseSchema`.
+    @discardableResult
+    public func prepareSchema() async throws -> DatabaseSchema {
+        try await ensureSchema()
+    }
+
+    /// The number of tables discovered during schema introspection.
+    /// Returns `nil` if the schema has not been introspected yet.
+    public var tableCount: Int? {
+        lock.withLock { schema?.tableNames.count }
+    }
+
+    /// The cached schema, if introspection has completed.
+    public var cachedSchema: DatabaseSchema? {
+        lock.withLock { schema }
+    }
+
+    /// Clears the conversation history and cached schema.
+    ///
+    /// After calling this, the next `send(_:)` call will re-introspect the
+    /// schema. Use ``clearHistory()`` if you only want to reset the conversation
+    /// while keeping the cached schema.
+    public func reset() {
+        lock.withLock {
+            conversationHistory.removeAll()
+            schema = nil
+        }
+    }
+
+    /// Clears only the conversation history, keeping the cached schema.
+    ///
+    /// This is useful when you want to start a fresh conversation thread
+    /// without re-introspecting the database. The schema cache remains valid
+    /// as long as the database structure hasn't changed.
+    public func clearHistory() {
+        lock.withLock {
+            conversationHistory.removeAll()
+        }
+    }
+
+    /// The current engine configuration.
+    public var currentConfiguration: ChatEngineConfiguration {
+        configuration
+    }
+
+    // MARK: - Internal Helpers (visible for testing)
+
+    /// Ensures the database schema is introspected and cached.
+    func ensureSchema() async throws -> DatabaseSchema {
+        if let cached = lock.withLock({ schema }) {
+            return cached
+        }
+
+        let introspected = try await SchemaIntrospector.introspect(database: database)
+
+        lock.withLock { schema = introspected }
+
+        return introspected
+    }
+
+    /// Asks the LLM to generate SQL from a natural language question.
+    /// Returns the raw LLM response text (before parsing).
+    ///
+    /// Uses the configured ``ChatEngineConfiguration/contextWindowSize`` to limit
+    /// how many conversation messages are included as context for the LLM.
+    private func generateRawResponse(
+        question: String,
+        promptBuilder: PromptBuilder
+    ) async throws -> String {
+        let instructions = promptBuilder.buildSystemInstructions()
+
+        // Build user prompt — include full conversation history for follow-ups
+        // Respect context window: only use recent messages for context
+        let userPrompt: String
+        let historySlice = lock.withLock { () -> [ChatMessage] in
+            Array(contextWindowSlice())
+        }
+
+        if historySlice.isEmpty {
+            userPrompt = promptBuilder.buildUserPrompt(question)
+        } else {
+            userPrompt = promptBuilder.buildConversationPrompt(
+                question,
+                history: historySlice
+            )
+        }
+
+        let session = LanguageModelSession(
+            model: model,
+            instructions: instructions + "\n\nRespond with ONLY the SQL query. No explanations, no markdown, no code fences."
+        )
+
+        let response = try await session.respond(to: userPrompt)
+        return response.content.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    /// Returns the conversation history slice within the configured context window.
+    /// Must be called within a `lock.withLock` closure.
+    private func contextWindowSlice() -> ArraySlice<ChatMessage> {
+        guard let windowSize = configuration.contextWindowSize else {
+            return conversationHistory[...]
+        }
+        let count = conversationHistory.count
+        let start = max(0, count - windowSize)
+        return conversationHistory[start...]
+    }
+
+    /// Runs all custom validators from the configuration against the parsed SQL.
+    private func runCustomValidators(parsed: ParsedSQL) throws {
+        for validator in configuration.validators {
+            try validator.validate(sql: parsed.sql, operation: parsed.operation)
+        }
+    }
+
+    /// Extracts the target table name from a SQL statement for delegate context.
+    private func extractTargetTableForDelegate(from sql: String, operation: SQLOperation) -> String? {
+        let pattern: String
+        switch operation {
+        case .insert:
+            pattern = #"INSERT\s+INTO\s+[`"\[]?(\w+)[`"\]]?"#
+        case .update:
+            pattern = #"UPDATE\s+[`"\[]?(\w+)[`"\]]?"#
+        case .delete:
+            pattern = #"DELETE\s+FROM\s+[`"\[]?(\w+)[`"\]]?"#
+        case .select:
+            return nil
+        }
+        guard let regex = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive) else {
+            return nil
+        }
+        let range = NSRange(sql.startIndex..., in: sql)
+        guard let match = regex.firstMatch(in: sql, range: range),
+              match.numberOfRanges > 1,
+              let groupRange = Range(match.range(at: 1), in: sql) else {
+            return nil
+        }
+        return String(sql[groupRange])
+    }
+
+    /// Executes SQL with the configured timeout, if any.
+    private func executeSQLWithTimeout(_ sql: String) async throws -> QueryResult {
+        guard let timeout = configuration.queryTimeout else {
+            return try await executeSQL(sql)
+        }
+
+        return try await withThrowingTaskGroup(of: QueryResult.self) { group in
+            group.addTask {
+                try await self.executeSQL(sql)
+            }
+
+            group.addTask {
+                try await Task.sleep(for: .seconds(timeout))
+                throw ChatEngineError.queryTimedOut(seconds: timeout)
+            }
+
+            // Return whichever finishes first
+            let result = try await group.next()!
+            group.cancelAll()
+            return result
+        }
+    }
+
+    /// Executes SQL against the database and returns a `QueryResult`.
+    private func executeSQL(_ sql: String) async throws -> QueryResult {
+        let trimmed = sql.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
+        let isSelect = trimmed.hasPrefix("SELECT") || trimmed.hasPrefix("WITH")
+
+        let startTime = CFAbsoluteTimeGetCurrent()
+
+        if isSelect {
+            let result = try await database.read { db -> (columns: [String], rows: [[String: QueryResult.Value]]) in
+                let statement = try db.makeStatement(sql: sql)
+                let columnNames = statement.columnNames
+
+                var rows: [[String: QueryResult.Value]] = []
+                let cursor = try Row.fetchCursor(statement)
+                while let row = try cursor.next() {
+                    var dict: [String: QueryResult.Value] = [:]
+                    for col in columnNames {
+                        dict[col] = Self.extractValue(row: row, column: col)
+                    }
+                    rows.append(dict)
+                }
+                return (columns: columnNames, rows: rows)
+            }
+
+            let elapsed = CFAbsoluteTimeGetCurrent() - startTime
+
+            return QueryResult(
+                columns: result.columns,
+                rows: result.rows,
+                sql: sql,
+                executionTime: elapsed
+            )
+        } else {
+            // Mutation query
+            let affected = try await database.write { db -> Int in
+                try db.execute(sql: sql)
+                return db.changesCount
+            }
+
+            let elapsed = CFAbsoluteTimeGetCurrent() - startTime
+
+            return QueryResult(
+                columns: [],
+                rows: [],
+                sql: sql,
+                executionTime: elapsed,
+                rowsAffected: affected
+            )
+        }
+    }
+
+    /// Extracts a `QueryResult.Value` from a GRDB `Row` for the given column.
+    private static func extractValue(row: Row, column: String) -> QueryResult.Value {
+        let dbValue: DatabaseValue = row[column]
+        switch dbValue.storage {
+        case .null:
+            return .null
+        case .int64(let i):
+            return .integer(i)
+        case .double(let d):
+            return .real(d)
+        case .string(let s):
+            return .text(s)
+        case .blob(let data):
+            return .blob(data)
+        }
+    }
+}
+
+// MARK: - Errors
+
+/// Errors that can occur during ChatEngine operations.
+public enum ChatEngineError: Error, LocalizedError, Sendable {
+    /// SQL parsing/extraction from LLM response failed.
+    case sqlParsingFailed(SQLParsingError)
+    /// A destructive operation requires user confirmation before execution.
+    case confirmationRequired(sql: String, operation: SQLOperation)
+    /// Schema introspection failed.
+    case schemaIntrospectionFailed(String)
+    /// The SQL query exceeded the configured timeout.
+    case queryTimedOut(seconds: TimeInterval)
+    /// A custom query validator rejected the query.
+    case validationFailed(String)
+
+    public var errorDescription: String? {
+        switch self {
+        case .sqlParsingFailed(let parsingError):
+            return "SQL parsing failed: \(parsingError.description)"
+        case .confirmationRequired(let sql, let op):
+            return "The \(op.rawValue.uppercased()) operation requires confirmation: \(sql)"
+        case .schemaIntrospectionFailed(let reason):
+            return "Failed to introspect database schema: \(reason)"
+        case .queryTimedOut(let seconds):
+            return "Query timed out after \(Int(seconds)) seconds."
+        case .validationFailed(let reason):
+            return "Query validation failed: \(reason)"
+        }
+    }
+}

Sources/SwiftDBAI/Engine/ToolExecutionDelegate.swift

@@ -0,0 +1,288 @@
+// ToolExecutionDelegate.swift
+// SwiftDBAI
+//
+// Delegate protocol for controlling SQL tool execution, including
+// confirmation of destructive operations before they reach the database.
+
+import Foundation
+
+// MARK: - Destructive SQL Classification
+
+/// Classifies SQL statements by their destructive potential.
+///
+/// A statement is considered **destructive** if it modifies or removes data
+/// or schema objects. The classification drives the confirmation flow:
+/// destructive statements require explicit user approval via
+/// ``ToolExecutionDelegate/confirmDestructiveOperation(_:)``.
+public enum DestructiveClassification: Sendable, Equatable {
+    /// The statement is read-only (e.g. SELECT). No confirmation needed.
+    case safe
+
+    /// The statement modifies existing data (INSERT, UPDATE).
+    case mutation(SQLStatementKind)
+
+    /// The statement deletes data or alters/drops schema objects.
+    /// These always require confirmation, even when the operation is allowed.
+    case destructive(SQLStatementKind)
+
+    /// Returns `true` when the statement requires user confirmation.
+    public var requiresConfirmation: Bool {
+        switch self {
+        case .safe:
+            return false
+        case .mutation:
+            return false
+        case .destructive:
+            return true
+        }
+    }
+
+    /// Returns `true` when the statement modifies data or schema in any way.
+    public var isMutating: Bool {
+        switch self {
+        case .safe:
+            return false
+        case .mutation, .destructive:
+            return true
+        }
+    }
+}
+
+/// The kind of SQL statement, used for classification and display.
+public enum SQLStatementKind: String, Sendable, Hashable, CaseIterable {
+    case select = "SELECT"
+    case insert = "INSERT"
+    case update = "UPDATE"
+    case delete = "DELETE"
+    case drop = "DROP"
+    case alter = "ALTER"
+    case truncate = "TRUNCATE"
+
+    /// All kinds that are classified as destructive.
+    public static let destructiveKinds: Set<SQLStatementKind> = [
+        .delete, .drop, .alter, .truncate
+    ]
+
+    /// All kinds that are classified as mutations (data-modifying but not destructive).
+    public static let mutationKinds: Set<SQLStatementKind> = [
+        .insert, .update
+    ]
+
+    /// Whether this kind of statement is destructive.
+    public var isDestructive: Bool {
+        Self.destructiveKinds.contains(self)
+    }
+
+    /// Whether this kind of statement is a mutation (INSERT/UPDATE).
+    public var isMutation: Bool {
+        Self.mutationKinds.contains(self)
+    }
+}
+
+// MARK: - Classification Function
+
+/// Classifies a SQL statement string by its destructive potential.
+///
+/// The classifier inspects the first keyword token of the statement
+/// (case-insensitive) to determine the statement kind, then maps it
+/// to a ``DestructiveClassification``.
+///
+/// - Parameter sql: The SQL statement to classify.
+/// - Returns: The classification for the statement.
+public func classifySQL(_ sql: String) -> DestructiveClassification {
+    guard let kind = detectStatementKind(sql) else {
+        return .safe
+    }
+
+    if kind.isDestructive {
+        return .destructive(kind)
+    } else if kind.isMutation {
+        return .mutation(kind)
+    } else {
+        return .safe
+    }
+}
+
+/// Detects the ``SQLStatementKind`` from the leading keyword of a SQL string.
+///
+/// - Parameter sql: The SQL statement to inspect.
+/// - Returns: The detected kind, or `nil` if unrecognized.
+public func detectStatementKind(_ sql: String) -> SQLStatementKind? {
+    let trimmed = sql.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
+
+    // Check each known statement kind against the first token
+    if trimmed.hasPrefix("SELECT") || trimmed.hasPrefix("WITH") {
+        return .select
+    } else if trimmed.hasPrefix("INSERT") {
+        return .insert
+    } else if trimmed.hasPrefix("UPDATE") {
+        return .update
+    } else if trimmed.hasPrefix("DELETE") {
+        return .delete
+    } else if trimmed.hasPrefix("DROP") {
+        return .drop
+    } else if trimmed.hasPrefix("ALTER") {
+        return .alter
+    } else if trimmed.hasPrefix("TRUNCATE") {
+        return .truncate
+    }
+
+    return nil
+}
+
+// MARK: - Destructive Operation Context
+
+/// Context provided to the delegate when a destructive operation needs confirmation.
+///
+/// Contains all the information a UI or programmatic handler needs to
+/// decide whether to allow the operation.
+public struct DestructiveOperationContext: Sendable {
+    /// The SQL statement that would be executed.
+    public let sql: String
+
+    /// The detected kind of statement (DELETE, DROP, ALTER, TRUNCATE).
+    public let statementKind: SQLStatementKind
+
+    /// The classification result.
+    public let classification: DestructiveClassification
+
+    /// A human-readable description of what the operation will do.
+    public let description: String
+
+    /// The target table name, if detected.
+    public let targetTable: String?
+
+    public init(
+        sql: String,
+        statementKind: SQLStatementKind,
+        classification: DestructiveClassification,
+        description: String,
+        targetTable: String? = nil
+    ) {
+        self.sql = sql
+        self.statementKind = statementKind
+        self.classification = classification
+        self.description = description
+        self.targetTable = targetTable
+    }
+}
+
+// MARK: - ToolExecutionDelegate Protocol
+
+/// A delegate that controls execution of SQL operations, providing
+/// confirmation gates for destructive statements.
+///
+/// Implement this protocol to intercept destructive SQL operations
+/// (DELETE, DROP, ALTER, TRUNCATE) before they are executed. The
+/// ``ChatEngine`` consults the delegate whenever it encounters a
+/// statement classified as ``DestructiveClassification/destructive(_:)``.
+///
+/// ## Example
+///
+/// ```swift
+/// struct MyDelegate: ToolExecutionDelegate {
+///     func confirmDestructiveOperation(
+///         _ context: DestructiveOperationContext
+///     ) async -> Bool {
+///         // Show a confirmation dialog to the user
+///         return await showAlert(
+///             "Confirm \(context.statementKind.rawValue)",
+///             message: context.description
+///         )
+///     }
+/// }
+///
+/// let engine = ChatEngine(
+///     database: pool,
+///     model: model,
+///     delegate: MyDelegate()
+/// )
+/// ```
+public protocol ToolExecutionDelegate: Sendable {
+
+    /// Called when a destructive SQL operation is about to be executed.
+    ///
+    /// The delegate should present the operation details to the user and
+    /// return `true` to proceed or `false` to cancel.
+    ///
+    /// - Parameter context: Details about the destructive operation.
+    /// - Returns: `true` to allow execution, `false` to reject it.
+    func confirmDestructiveOperation(
+        _ context: DestructiveOperationContext
+    ) async -> Bool
+
+    /// Called before any SQL statement is executed.
+    ///
+    /// This is an observation hook — the engine does not wait for a
+    /// decision. Override to log, audit, or instrument queries.
+    ///
+    /// - Parameters:
+    ///   - sql: The SQL about to be executed.
+    ///   - classification: The destructive classification of the statement.
+    func willExecuteSQL(
+        _ sql: String,
+        classification: DestructiveClassification
+    ) async
+
+    /// Called after a SQL statement completes execution.
+    ///
+    /// - Parameters:
+    ///   - sql: The SQL that was executed.
+    ///   - success: Whether execution succeeded.
+    func didExecuteSQL(
+        _ sql: String,
+        success: Bool
+    ) async
+}
+
+// MARK: - Default Implementations
+
+extension ToolExecutionDelegate {
+    /// Default: rejects all destructive operations.
+    public func confirmDestructiveOperation(
+        _ context: DestructiveOperationContext
+    ) async -> Bool {
+        false
+    }
+
+    /// Default: no-op.
+    public func willExecuteSQL(
+        _ sql: String,
+        classification: DestructiveClassification
+    ) async {}
+
+    /// Default: no-op.
+    public func didExecuteSQL(
+        _ sql: String,
+        success: Bool
+    ) async {}
+}
+
+// MARK: - Built-in Delegates
+
+/// A delegate that automatically approves all destructive operations.
+///
+/// Use this only in testing or trusted environments where confirmation
+/// is not needed.
+public struct AutoApproveDelegate: ToolExecutionDelegate {
+    public init() {}
+
+    public func confirmDestructiveOperation(
+        _ context: DestructiveOperationContext
+    ) async -> Bool {
+        true
+    }
+}
+
+/// A delegate that always rejects destructive operations.
+///
+/// This is the safest option and matches the default behavior.
+public struct RejectAllDelegate: ToolExecutionDelegate {
+    public init() {}
+
+    public func confirmDestructiveOperation(
+        _ context: DestructiveOperationContext
+    ) async -> Bool {
+        false
+    }
+}

Sources/SwiftDBAI/Models/ConversationHistory.swift

@@ -0,0 +1,143 @@
+// ConversationHistory.swift
+// SwiftDBAI
+//
+// Ordered chat message history with configurable context window.
+
+import Foundation
+
+/// Stores an ordered sequence of ``ChatMessage`` instances with a configurable
+/// context window limit.
+///
+/// When the number of messages exceeds ``maxMessages``, the oldest messages are
+/// trimmed to keep the history within budget. This prevents unbounded token
+/// growth when building LLM prompts from conversation history.
+///
+/// Usage:
+/// ```swift
+/// var history = ConversationHistory(maxMessages: 20)
+/// history.append(ChatMessage(role: .user, content: "How many users?"))
+/// history.append(ChatMessage(role: .assistant, content: "42", sql: "SELECT COUNT(*) FROM users"))
+/// print(history.promptText) // formatted for LLM context
+/// ```
+public struct ConversationHistory: Sendable {
+
+    /// The maximum number of messages to retain. `nil` means unlimited.
+    public let maxMessages: Int?
+
+    /// All messages in chronological order.
+    public private(set) var messages: [ChatMessage] = []
+
+    /// Creates a new conversation history.
+    ///
+    /// - Parameter maxMessages: Maximum number of messages to keep in the
+    ///   context window. Pass `nil` for unlimited history. Defaults to 50.
+    public init(maxMessages: Int? = 50) {
+        precondition(maxMessages == nil || maxMessages! > 0,
+                     "maxMessages must be positive or nil")
+        self.maxMessages = maxMessages
+    }
+
+    /// The number of messages currently stored.
+    public var count: Int { messages.count }
+
+    /// Whether the history is empty.
+    public var isEmpty: Bool { messages.isEmpty }
+
+    // MARK: - Mutating Operations
+
+    /// Appends a message and trims the history if it exceeds the context window.
+    public mutating func append(_ message: ChatMessage) {
+        messages.append(message)
+        trimIfNeeded()
+    }
+
+    /// Appends multiple messages and trims once afterward.
+    public mutating func append(contentsOf newMessages: [ChatMessage]) {
+        messages.append(contentsOf: newMessages)
+        trimIfNeeded()
+    }
+
+    /// Removes all messages from the history.
+    public mutating func clear() {
+        messages.removeAll()
+    }
+
+    // MARK: - Context Window
+
+    /// Returns the most recent messages formatted for inclusion in an LLM prompt.
+    ///
+    /// Each message is formatted as `[role] content`, with SQL and query results
+    /// included inline for assistant messages.
+    ///
+    /// - Parameter limit: Optional override to further restrict the number of
+    ///   messages returned. When `nil`, uses the full retained history.
+    /// - Returns: An array of prompt-formatted strings, one per message.
+    public func promptMessages(limit: Int? = nil) -> [String] {
+        let slice: ArraySlice<ChatMessage>
+        if let limit {
+            slice = messages.suffix(limit)
+        } else {
+            slice = messages[...]
+        }
+        return slice.map { message in
+            Self.formatForPrompt(message)
+        }
+    }
+
+    /// Returns the combined prompt text for all retained messages, separated by
+    /// double newlines.
+    public var promptText: String {
+        promptMessages().joined(separator: "\n\n")
+    }
+
+    // MARK: - Queries
+
+    /// Returns only user messages.
+    public var userMessages: [ChatMessage] {
+        messages.filter { $0.role == .user }
+    }
+
+    /// Returns only assistant messages.
+    public var assistantMessages: [ChatMessage] {
+        messages.filter { $0.role == .assistant }
+    }
+
+    /// Returns the last message, if any.
+    public var lastMessage: ChatMessage? {
+        messages.last
+    }
+
+    /// Returns the most recent user query text, if any.
+    public var lastUserQuery: String? {
+        messages.last(where: { $0.role == .user })?.content
+    }
+
+    /// Returns the most recent assistant message, if any.
+    public var lastAssistantMessage: ChatMessage? {
+        messages.last(where: { $0.role == .assistant })
+    }
+
+    // MARK: - Private
+
+    /// Formats a ``ChatMessage`` into a string suitable for LLM prompt context.
+    private static func formatForPrompt(_ message: ChatMessage) -> String {
+        var parts: [String] = ["[\(message.role.rawValue)] \(message.content)"]
+
+        if let sql = message.sql {
+            parts.append("SQL: \(sql)")
+        }
+
+        if let result = message.queryResult {
+            parts.append("Result:\n\(result.tabularDescription)")
+        }
+
+        return parts.joined(separator: "\n")
+    }
+
+    /// Trims the oldest messages to stay within the context window.
+    private mutating func trimIfNeeded() {
+        guard let max = maxMessages, messages.count > max else { return }
+        let overflow = messages.count - max
+        messages.removeFirst(overflow)
+    }
+}

Sources/SwiftDBAI/Models/QueryResult.swift

@@ -0,0 +1,136 @@
+// QueryResult.swift
+// SwiftDBAI
+//
+// Structured result from SQL query execution.
+
+import Foundation
+
+/// Represents the result of executing a SQL query against the database.
+///
+/// Contains raw row data as dictionaries, column metadata, row count,
+/// the original SQL string, and execution timing.
+public struct QueryResult: Sendable, Equatable {
+
+    /// A single cell value from a query result.
+    ///
+    /// Wraps SQLite's dynamic value types into a type-safe, Sendable enum.
+    public enum Value: Sendable, Equatable, CustomStringConvertible {
+        case text(String)
+        case integer(Int64)
+        case real(Double)
+        case blob(Data)
+        case null
+
+        public var description: String {
+            switch self {
+            case .text(let s): return s
+            case .integer(let i): return String(i)
+            case .real(let d):
+                if d == d.rounded() && abs(d) < 1e15 {
+                    return String(format: "%.0f", d)
+                }
+                return String(d)
+            case .blob(let data): return "<\(data.count) bytes>"
+            case .null: return "NULL"
+            }
+        }
+
+        /// Returns the value as a `Double` if it is numeric, nil otherwise.
+        public var doubleValue: Double? {
+            switch self {
+            case .integer(let i): return Double(i)
+            case .real(let d): return d
+            case .text(let s): return Double(s)
+            default: return nil
+            }
+        }
+
+        /// Returns the value as a `String` (non-nil for all cases).
+        public var stringValue: String { description }
+
+        /// Returns `true` if this value is `.null`.
+        public var isNull: Bool {
+            if case .null = self { return true }
+            return false
+        }
+    }
+
+    /// Column names in the order they appear in the result set.
+    public let columns: [String]
+
+    /// Row data as an array of dictionaries mapping column name to value.
+    public let rows: [[String: Value]]
+
+    /// Total number of rows returned.
+    public var rowCount: Int { rows.count }
+
+    /// The SQL statement that was executed.
+    public let sql: String
+
+    /// Time taken to execute the query, in seconds.
+    public let executionTime: TimeInterval
+
+    /// Number of rows affected (for INSERT/UPDATE/DELETE). Nil for SELECT.
+    public let rowsAffected: Int?
+
+    public init(
+        columns: [String],
+        rows: [[String: Value]],
+        sql: String,
+        executionTime: TimeInterval,
+        rowsAffected: Int? = nil
+    ) {
+        self.columns = columns
+        self.rows = rows
+        self.sql = sql
+        self.executionTime = executionTime
+        self.rowsAffected = rowsAffected
+    }
+
+    // MARK: - Convenience Accessors
+
+    /// Returns all values for a given column, in row order.
+    public func values(forColumn column: String) -> [Value] {
+        rows.compactMap { $0[column] }
+    }
+
+    /// Returns a compact tabular string representation of the results.
+    ///
+    /// Useful for embedding query results into LLM prompts.
+    public var tabularDescription: String {
+        guard !rows.isEmpty else {
+            return "(empty result set)"
+        }
+
+        var lines: [String] = []
+
+        // Header
+        lines.append(columns.joined(separator: " | "))
+        lines.append(String(repeating: "-", count: lines[0].count))
+
+        // Rows (cap at 50 for prompt size)
+        let displayRows = rows.prefix(50)
+        for row in displayRows {
+            let vals = columns.map { col in
+                row[col]?.description ?? "NULL"
+            }
+            lines.append(vals.joined(separator: " | "))
+        }
+
+        if rows.count > 50 {
+            lines.append("... and \(rows.count - 50) more rows")
+        }
+
+        return lines.joined(separator: "\n")
+    }
+
+    /// Returns true if the result looks like a single aggregate value
+    /// (1 row, 1-3 columns, all numeric).
+    public var isAggregate: Bool {
+        guard rowCount == 1, columns.count <= 3 else { return false }
+        let firstRow = rows[0]
+        return columns.allSatisfy { col in
+            firstRow[col]?.doubleValue != nil
+        }
+    }
+}

Sources/SwiftDBAI/Parsing/SQLQueryParser.swift

@@ -0,0 +1,380 @@
+// SQLQueryParser.swift
+// SwiftDBAI
+//
+// Extracts and validates SQL statements from raw LLM response text.
+
+import Foundation
+
+/// Errors that can occur during SQL parsing and validation.
+public enum SQLParsingError: Error, Sendable, Equatable, CustomStringConvertible {
+    /// No SQL statement could be found in the LLM response.
+    case noSQLFound
+
+    /// The SQL statement uses an operation not in the allowlist.
+    case operationNotAllowed(SQLOperation)
+
+    /// A destructive operation (DELETE) requires user confirmation.
+    case confirmationRequired(sql: String, operation: SQLOperation)
+
+    /// The mutation targets a table not in the allowed mutation tables.
+    case tableNotAllowed(table: String, operation: SQLOperation)
+
+    /// The SQL contains a disallowed keyword (e.g., DROP, ALTER, TRUNCATE).
+    case dangerousOperation(String)
+
+    /// Multiple SQL statements were found but only single-statement execution is supported.
+    case multipleStatements
+
+    public var description: String {
+        switch self {
+        case .noSQLFound:
+            return "No SQL statement found in the response."
+        case .operationNotAllowed(let op):
+            return "Operation '\(op.rawValue.uppercased())' is not allowed by the current configuration."
+        case .confirmationRequired(let sql, let op):
+            return "The \(op.rawValue.uppercased()) operation requires confirmation: \(sql)"
+        case .tableNotAllowed(let table, let op):
+            return "The \(op.rawValue.uppercased()) operation is not allowed on table '\(table)'."
+        case .dangerousOperation(let keyword):
+            return "Dangerous SQL operation '\(keyword)' is never allowed."
+        case .multipleStatements:
+            return "Only single SQL statements are supported."
+        }
+    }
+}
+
+/// Result of successfully parsing SQL from an LLM response.
+public struct ParsedSQL: Sendable, Equatable {
+    /// The cleaned SQL statement ready for execution.
+    public let sql: String
+
+    /// The detected operation type.
+    public let operation: SQLOperation
+
+    /// Whether this operation requires user confirmation before execution.
+    public let requiresConfirmation: Bool
+
+    public init(sql: String, operation: SQLOperation, requiresConfirmation: Bool = false) {
+        self.sql = sql
+        self.operation = operation
+        self.requiresConfirmation = requiresConfirmation
+    }
+}
+
+/// Extracts SQL statements from raw LLM response text and validates them
+/// against the configured ``OperationAllowlist``.
+///
+/// The parser handles common LLM output patterns:
+/// - SQL in markdown code blocks (```sql ... ```)
+/// - SQL in generic code blocks (``` ... ```)
+/// - Raw SQL statements in plain text
+/// - SQL prefixed with labels like "SQL:" or "Query:"
+public struct SQLQueryParser: Sendable {
+
+    /// Keywords that are never allowed regardless of allowlist configuration.
+    private static let dangerousKeywords: Set<String> = [
+        "DROP", "ALTER", "TRUNCATE", "CREATE", "GRANT", "REVOKE",
+        "ATTACH", "DETACH", "PRAGMA", "VACUUM", "REINDEX"
+    ]
+
+    /// The operation allowlist to validate against.
+    private let allowlist: OperationAllowlist
+
+    /// The mutation policy for table-level restrictions.
+    private let mutationPolicy: MutationPolicy?
+
+    /// Creates a parser with the given operation allowlist.
+    /// - Parameter allowlist: The set of permitted operations. Defaults to read-only.
+    public init(allowlist: OperationAllowlist = .readOnly) {
+        self.allowlist = allowlist
+        self.mutationPolicy = nil
+    }
+
+    /// Creates a parser with a mutation policy (preferred initializer).
+    /// - Parameter mutationPolicy: The mutation policy controlling operations and table access.
+    public init(mutationPolicy: MutationPolicy) {
+        self.allowlist = mutationPolicy.operationAllowlist
+        self.mutationPolicy = mutationPolicy
+    }
+
+    /// Extracts and validates a SQL statement from raw LLM response text.
+    ///
+    /// - Parameter text: The raw text from the LLM response.
+    /// - Returns: A ``ParsedSQL`` containing the validated statement.
+    /// - Throws: ``SQLParsingError`` if extraction or validation fails.
+    public func parse(_ text: String) throws -> ParsedSQL {
+        let sql = try extractSQL(from: text)
+        return try validate(sql)
+    }
+
+    // MARK: - Extraction
+
+    /// Attempts to extract a SQL statement from the LLM response text.
+    /// Tries multiple strategies in order of confidence.
+    func extractSQL(from text: String) throws -> String {
+        // Strategy 1: SQL in markdown fenced code block with sql language tag
+        if let sql = extractFromSQLCodeBlock(text) {
+            return sql
+        }
+
+        // Strategy 2: SQL in generic fenced code block
+        if let sql = extractFromGenericCodeBlock(text) {
+            return sql
+        }
+
+        // Strategy 3: SQL after a label like "SQL:" or "Query:"
+        if let sql = extractFromLabel(text) {
+            return sql
+        }
+
+        // Strategy 4: Direct SQL detection in plain text
+        if let sql = extractDirectSQL(text) {
+            return sql
+        }
+
+        throw SQLParsingError.noSQLFound
+    }
+
+    /// Extracts SQL from a ```sql ... ``` code block.
+    private func extractFromSQLCodeBlock(_ text: String) -> String? {
+        let pattern = #"```sql\s*\n([\s\S]*?)```"#
+        return firstMatch(pattern: pattern, in: text, group: 1)?
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+            .nonEmptyOrNil
+    }
+
+    /// Extracts SQL from a generic ``` ... ``` code block.
+    private func extractFromGenericCodeBlock(_ text: String) -> String? {
+        let pattern = #"```\s*\n([\s\S]*?)```"#
+        guard let content = firstMatch(pattern: pattern, in: text, group: 1)?
+            .trimmingCharacters(in: .whitespacesAndNewlines) else {
+            return nil
+        }
+        // Only accept if it looks like SQL
+        guard looksLikeSQL(content) else { return nil }
+        return content.nonEmptyOrNil
+    }
+
+    /// Extracts SQL after labels like "SQL:", "Query:", "Here's the query:"
+    private func extractFromLabel(_ text: String) -> String? {
+        // Match the SQL keyword up to end-of-line (handling multi-line SQL with indentation)
+        let pattern = #"(?:SQL|Query|Statement)\s*:\s*\n?\s*((?:SELECT|INSERT|UPDATE|DELETE|WITH)\b.+?)(?:\n(?!\s)|$)"#
+        guard let content = firstMatch(pattern: pattern, in: text, group: 1, options: [.caseInsensitive, .dotMatchesLineSeparators])?
+            .trimmingCharacters(in: .whitespacesAndNewlines) else {
+            return nil
+        }
+        guard looksLikeSQL(content) else { return nil }
+        return content.nonEmptyOrNil
+    }
+
+    /// Detects SQL directly in the text by matching known statement patterns.
+    private func extractDirectSQL(_ text: String) -> String? {
+        // Match SQL statement, allowing semicolons inside single-quoted string literals
+        let pattern = #"(?:^|\n)\s*((?:SELECT|INSERT|UPDATE|DELETE)\b(?:[^;']|'[^']*')*;?)"#
+        guard let content = firstMatch(pattern: pattern, in: text, group: 1, options: .caseInsensitive)?
+            .trimmingCharacters(in: .whitespacesAndNewlines) else {
+            return nil
+        }
+        return content.nonEmptyOrNil
+    }
+
+    // MARK: - Validation
+
+    /// Validates a SQL string against the allowlist and safety rules.
+    func validate(_ sql: String) throws -> ParsedSQL {
+        let cleaned = cleanSQL(sql)
+
+        guard !cleaned.isEmpty else {
+            throw SQLParsingError.noSQLFound
+        }
+
+        // Check for multiple statements (semicolons in non-trivial positions)
+        if containsMultipleStatements(cleaned) {
+            throw SQLParsingError.multipleStatements
+        }
+
+        // Check for dangerous operations first (before allowlist)
+        try checkDangerousKeywords(cleaned)
+
+        // Detect the operation type
+        let operation = detectOperation(cleaned)
+
+        // Check against the allowlist
+        guard allowlist.isAllowed(operation) else {
+            throw SQLParsingError.operationNotAllowed(operation)
+        }
+
+        // Check table-level restrictions for mutation operations
+        if let policy = mutationPolicy, operation != .select,
+           let targetTable = extractTargetTable(from: cleaned, operation: operation) {
+            guard policy.isAllowed(operation: operation, on: targetTable) else {
+                throw SQLParsingError.tableNotAllowed(table: targetTable, operation: operation)
+            }
+        }
+
+        // DELETE requires confirmation when policy says so, or always by default
+        let requiresConfirmation: Bool
+        if let policy = mutationPolicy {
+            requiresConfirmation = policy.requiresConfirmation(for: operation)
+        } else {
+            requiresConfirmation = operation == .delete
+        }
+
+        return ParsedSQL(
+            sql: cleaned,
+            operation: operation,
+            requiresConfirmation: requiresConfirmation
+        )
+    }
+
+    // MARK: - Helpers
+
+    /// Cleans a SQL string by removing trailing semicolons (outside string literals) and excess whitespace.
+    private func cleanSQL(_ sql: String) -> String {
+        var cleaned = sql.trimmingCharacters(in: .whitespacesAndNewlines)
+        // Remove trailing semicolons only if they're outside string literals
+        while cleaned.hasSuffix(";") && !isInsideStringLiteral(sql: cleaned, position: cleaned.index(before: cleaned.endIndex)) {
+            cleaned = String(cleaned.dropLast()).trimmingCharacters(in: .whitespacesAndNewlines)
+        }
+        // Collapse internal whitespace outside string literals
+        cleaned = collapseWhitespace(cleaned)
+        return cleaned
+    }
+
+    /// Collapses whitespace while preserving string literal contents.
+    private func collapseWhitespace(_ sql: String) -> String {
+        var result = ""
+        var inString = false
+        var prevWasSpace = false
+        for ch in sql {
+            if ch == "'" {
+                inString.toggle()
+                prevWasSpace = false
+                result.append(ch)
+            } else if inString {
+                result.append(ch)
+            } else if ch.isWhitespace {
+                if !prevWasSpace {
+                    result.append(" ")
+                    prevWasSpace = true
+                }
+            } else {
+                prevWasSpace = false
+                result.append(ch)
+            }
+        }
+        return result
+    }
+
+    /// Returns true if the character at the given position is inside a single-quoted string literal.
+    private func isInsideStringLiteral(sql: String, position: String.Index) -> Bool {
+        var inString = false
+        for idx in sql.indices {
+            if idx == position { return inString }
+            if sql[idx] == "'" { inString.toggle() }
+        }
+        return false
+    }
+
+    /// Checks whether cleaned SQL contains multiple statements.
+    private func containsMultipleStatements(_ sql: String) -> Bool {
+        // Remove string literals before checking for semicolons
+        var inString = false
+        for ch in sql {
+            if ch == "'" {
+                inString.toggle()
+            } else if ch == ";" && !inString {
+                return true
+            }
+        }
+        return false
+    }
+
+    /// Checks for dangerous SQL keywords that are never allowed.
+    private func checkDangerousKeywords(_ sql: String) throws {
+        let upper = sql.uppercased()
+        // Tokenize to avoid partial matches (e.g., "DROPDOWN" matching "DROP")
+        let tokens = upper.components(separatedBy: .alphanumerics.inverted)
+            .filter { !$0.isEmpty }
+
+        for keyword in Self.dangerousKeywords {
+            if tokens.contains(keyword) {
+                throw SQLParsingError.dangerousOperation(keyword)
+            }
+        }
+    }
+
+    /// Detects the SQL operation type from the first keyword.
+    private func detectOperation(_ sql: String) -> SQLOperation {
+        let upper = sql.uppercased().trimmingCharacters(in: .whitespaces)
+
+        if upper.hasPrefix("SELECT") || upper.hasPrefix("WITH") {
+            return .select
+        } else if upper.hasPrefix("INSERT") {
+            return .insert
+        } else if upper.hasPrefix("UPDATE") {
+            return .update
+        } else if upper.hasPrefix("DELETE") {
+            return .delete
+        }
+
+        // Default to select for unrecognized patterns (e.g. EXPLAIN)
+        return .select
+    }
+
+    /// Extracts the target table name from a mutation SQL statement.
+    ///
+    /// Handles common patterns:
+    /// - `INSERT INTO table_name ...`
+    /// - `UPDATE table_name SET ...`
+    /// - `DELETE FROM table_name ...`
+    private func extractTargetTable(from sql: String, operation: SQLOperation) -> String? {
+        let pattern: String
+        switch operation {
+        case .insert:
+            pattern = #"INSERT\s+INTO\s+[`"\[]?(\w+)[`"\]]?"#
+        case .update:
+            pattern = #"UPDATE\s+[`"\[]?(\w+)[`"\]]?"#
+        case .delete:
+            pattern = #"DELETE\s+FROM\s+[`"\[]?(\w+)[`"\]]?"#
+        case .select:
+            return nil
+        }
+        return firstMatch(pattern: pattern, in: sql, group: 1, options: .caseInsensitive)
+    }
+
+    /// Returns true if the text looks like a SQL statement.
+    private func looksLikeSQL(_ text: String) -> Bool {
+        let upper = text.uppercased().trimmingCharacters(in: .whitespaces)
+        let sqlPrefixes = ["SELECT", "INSERT", "UPDATE", "DELETE", "WITH"]
+        return sqlPrefixes.contains { upper.hasPrefix($0) }
+    }
+
+    /// Extracts the first regex match group from the text.
+    private func firstMatch(
+        pattern: String,
+        in text: String,
+        group: Int,
+        options: NSRegularExpression.Options = []
+    ) -> String? {
+        guard let regex = try? NSRegularExpression(pattern: pattern, options: options) else {
+            return nil
+        }
+        let range = NSRange(text.startIndex..., in: text)
+        guard let match = regex.firstMatch(in: text, range: range),
+              match.numberOfRanges > group,
+              let groupRange = Range(match.range(at: group), in: text) else {
+            return nil
+        }
+        return String(text[groupRange])
+    }
+}
+
+// MARK: - String Extension
+
+private extension String {
+    /// Returns nil if the string is empty, otherwise returns self.
+    var nonEmptyOrNil: String? {
+        isEmpty ? nil : self
+    }
+}

Sources/SwiftDBAI/Prompt/PromptBuilder.swift

@@ -0,0 +1,211 @@
+/// Builds structured LLM prompts for SQL generation from a database schema
+/// and natural language input.
+///
+/// `PromptBuilder` is the bridge between the introspected database schema and
+/// the LLM. It produces two things:
+/// 1. A **system instructions** string containing schema context and behavioral rules
+/// 2. A **user prompt** string wrapping the natural language question
+///
+/// Usage:
+/// ```swift
+/// let builder = PromptBuilder(schema: mySchema, allowlist: .readOnly)
+/// let instructions = builder.buildSystemInstructions()
+/// let prompt = builder.buildUserPrompt("How many users signed up this week?")
+/// ```
+public struct PromptBuilder: Sendable {
+    /// The database schema to include as context.
+    public let schema: DatabaseSchema
+
+    /// Which SQL operations the LLM may generate.
+    public let allowlist: OperationAllowlist
+
+    /// Optional additional context to append to the system instructions
+    /// (e.g., business-specific terminology or query hints).
+    public let additionalContext: String?
+
+    /// Creates a prompt builder for the given schema and allowlist.
+    ///
+    /// - Parameters:
+    ///   - schema: The introspected database schema.
+    ///   - allowlist: Permitted SQL operations. Defaults to ``OperationAllowlist/readOnly``.
+    ///   - additionalContext: Extra instructions appended to the system prompt.
+    public init(
+        schema: DatabaseSchema,
+        allowlist: OperationAllowlist = .readOnly,
+        additionalContext: String? = nil
+    ) {
+        self.schema = schema
+        self.allowlist = allowlist
+        self.additionalContext = additionalContext
+    }
+
+    // MARK: - System Instructions
+
+    /// Builds the system instructions string that should be passed as the
+    /// `instructions` parameter when creating a `LanguageModelSession`.
+    ///
+    /// The instructions include:
+    /// - Role definition
+    /// - The full database schema
+    /// - SQL generation rules and constraints
+    /// - The operation allowlist
+    /// - Output format requirements
+    public func buildSystemInstructions() -> String {
+        var sections: [String] = []
+
+        // 1. Role
+        sections.append(Self.roleSection)
+
+        // 2. Schema
+        sections.append(buildSchemaSection())
+
+        // 3. Operation permissions
+        sections.append(buildPermissionsSection())
+
+        // 4. SQL generation rules
+        sections.append(Self.sqlRulesSection)
+
+        // 5. Output format
+        sections.append(Self.outputFormatSection)
+
+        // 6. Additional context
+        if let additionalContext, !additionalContext.isEmpty {
+            sections.append("ADDITIONAL CONTEXT\n=================\n\(additionalContext)")
+        }
+
+        return sections.joined(separator: "\n\n")
+    }
+
+    // MARK: - User Prompt
+
+    /// Wraps a natural language question into a user prompt string.
+    ///
+    /// - Parameter question: The user's natural language question.
+    /// - Returns: A formatted prompt string for the LLM.
+    public func buildUserPrompt(_ question: String) -> String {
+        question
+    }
+
+    /// Builds a follow-up prompt that includes prior SQL context for
+    /// multi-turn conversations.
+    ///
+    /// - Parameters:
+    ///   - question: The user's follow-up question.
+    ///   - previousSQL: The SQL from the previous turn, for context.
+    ///   - previousResultSummary: A brief summary of what the previous query returned.
+    /// - Returns: A formatted prompt string.
+    public func buildFollowUpPrompt(
+        _ question: String,
+        previousSQL: String,
+        previousResultSummary: String
+    ) -> String {
+        """
+        Previous query: \(previousSQL)
+        Previous result: \(previousResultSummary)
+
+        Follow-up question: \(question)
+        """
+    }
+
+    /// Builds a prompt that includes the full conversation history within the
+    /// configured context window, enabling the LLM to resolve follow-up
+    /// references (pronouns, implicit table/column references, etc.).
+    ///
+    /// - Parameters:
+    ///   - question: The user's current question.
+    ///   - history: The conversation history messages within the context window.
+    /// - Returns: A formatted prompt string with conversation context.
+    public func buildConversationPrompt(
+        _ question: String,
+        history: [ChatMessage]
+    ) -> String {
+        guard !history.isEmpty else {
+            return buildUserPrompt(question)
+        }
+
+        var lines: [String] = []
+        lines.append("CONVERSATION HISTORY")
+        lines.append("====================")
+
+        for message in history {
+            switch message.role {
+            case .user:
+                lines.append("User: \(message.content)")
+            case .assistant:
+                if let sql = message.sql {
+                    lines.append("Assistant SQL: \(sql)")
+                }
+                lines.append("Assistant: \(message.content)")
+            case .error:
+                lines.append("Error: \(message.content)")
+            }
+        }
+
+        lines.append("")
+        lines.append("CURRENT QUESTION")
+        lines.append("================")
+        lines.append(question)
+
+        return lines.joined(separator: "\n")
+    }
+
+    // MARK: - Private Sections
+
+    private func buildSchemaSection() -> String {
+        var lines: [String] = []
+        lines.append("DATABASE SCHEMA")
+        lines.append("===============")
+        lines.append("")
+        lines.append(schema.schemaDescription)
+        return lines.joined(separator: "\n")
+    }
+
+    private func buildPermissionsSection() -> String {
+        var lines: [String] = []
+        lines.append("PERMISSIONS")
+        lines.append("===========")
+        lines.append(allowlist.describeForLLM())
+        return lines.joined(separator: "\n")
+    }
+
+    // MARK: - Static Content
+
+    static let roleSection = """
+        ROLE
+        ====
+        You are a SQL assistant for a SQLite database. Your job is to translate \
+        natural language questions into valid SQLite SQL queries based on the \
+        database schema provided below. You must ONLY reference tables and columns \
+        that exist in the schema. Never fabricate table or column names.
+        """
+
+    static let sqlRulesSection = """
+        SQL GENERATION RULES
+        ====================
+        1. Use ONLY the tables and columns listed in the schema above.
+        2. Use SQLite-compatible syntax (e.g., || for string concatenation, \
+        IFNULL instead of COALESCE where needed).
+        3. Use appropriate JOINs when queries span multiple tables — reference \
+        the foreign key relationships in the schema.
+        4. For date/time operations, use SQLite date functions \
+        (date(), time(), datetime(), strftime()).
+        5. Use parameterized-style values where possible. For literal values \
+        from the user's question, embed them directly in the SQL.
+        6. Always include an ORDER BY clause when the user implies ordering.
+        7. Use LIMIT when the user asks for "top N" or "first N" results.
+        8. For aggregate queries (count, sum, average, min, max), use the \
+        appropriate SQL aggregate functions.
+        9. When the user's question is ambiguous, prefer the simplest valid \
+        interpretation.
+        10. Never generate DDL statements (CREATE, ALTER, DROP TABLE).
+        """
+
+    static let outputFormatSection = """
+        OUTPUT FORMAT
+        =============
+        When generating SQL, call the appropriate tool with the SQL query. \
+        After receiving query results, provide a concise natural language \
+        summary of the data. Be specific with numbers and names from the results. \
+        If no rows are returned, say so clearly.
+        """
+}

Sources/SwiftDBAI/Rendering/ChartDataDetector.swift

@@ -0,0 +1,423 @@
+// ChartDataDetector.swift
+// SwiftDBAI
+//
+// Analyzes query results to determine chart eligibility and
+// recommends appropriate chart types based on data shape.
+
+import Foundation
+
+/// Detects whether a `DataTable` is suitable for charting and
+/// recommends the best chart type based on data shape heuristics.
+///
+/// The detector examines column types, row counts, and value distributions
+/// to produce a `ChartRecommendation` that the rendering layer can use
+/// to auto-select an appropriate Swift Charts visualization.
+///
+/// Usage:
+/// ```swift
+/// let detector = ChartDataDetector()
+/// if let recommendation = detector.detect(table) {
+///     switch recommendation.chartType {
+///     case .bar:  // render bar chart
+///     case .line: // render line chart
+///     case .pie:  // render pie chart
+///     }
+/// }
+/// ```
+public struct ChartDataDetector: Sendable {
+
+    // MARK: - Chart Types
+
+    /// The type of chart recommended for the data.
+    public enum ChartType: String, Sendable, Equatable, CaseIterable {
+        /// Vertical bar chart — best for categorical comparisons.
+        case bar
+        /// Line chart — best for time series or ordered sequences.
+        case line
+        /// Pie/donut chart — best for proportional breakdowns with few categories.
+        case pie
+    }
+
+    /// A recommendation for how to chart a `DataTable`.
+    public struct ChartRecommendation: Sendable, Equatable {
+        /// The recommended chart type.
+        public let chartType: ChartType
+
+        /// The column to use for the category axis (x-axis / labels).
+        public let categoryColumn: String
+
+        /// The column to use for the value axis (y-axis / sizes).
+        public let valueColumn: String
+
+        /// Confidence score from 0.0 (guess) to 1.0 (strong match).
+        public let confidence: Double
+
+        /// Human-readable reason for this recommendation.
+        public let reason: String
+
+        public init(
+            chartType: ChartType,
+            categoryColumn: String,
+            valueColumn: String,
+            confidence: Double,
+            reason: String
+        ) {
+            self.chartType = chartType
+            self.categoryColumn = categoryColumn
+            self.valueColumn = valueColumn
+            self.confidence = confidence
+            self.reason = reason
+        }
+    }
+
+    // MARK: - Configuration
+
+    /// Minimum rows required to consider chart-eligible.
+    public let minimumRows: Int
+
+    /// Maximum rows for a pie chart (too many slices becomes unreadable).
+    public let maxPieSlices: Int
+
+    /// Maximum rows for any chart before it becomes cluttered.
+    public let maximumRows: Int
+
+    // MARK: - Initialization
+
+    /// Creates a detector with configurable thresholds.
+    ///
+    /// - Parameters:
+    ///   - minimumRows: Minimum rows for chart eligibility (default: 2).
+    ///   - maxPieSlices: Maximum categories for pie charts (default: 8).
+    ///   - maximumRows: Maximum rows for any chart (default: 100).
+    public init(
+        minimumRows: Int = 2,
+        maxPieSlices: Int = 8,
+        maximumRows: Int = 100
+    ) {
+        self.minimumRows = minimumRows
+        self.maxPieSlices = maxPieSlices
+        self.maximumRows = maximumRows
+    }
+
+    // MARK: - Detection
+
+    /// Analyzes a `DataTable` and returns a chart recommendation, or `nil`
+    /// if the data is not suitable for charting.
+    ///
+    /// - Parameter table: The data table to analyze.
+    /// - Returns: A recommendation, or `nil` if no chart type fits.
+    public func detect(_ table: DataTable) -> ChartRecommendation? {
+        // Must have at least 2 columns (category + value) and enough rows
+        guard table.columnCount >= 2,
+              table.rowCount >= minimumRows,
+              table.rowCount <= maximumRows else {
+            return nil
+        }
+
+        // Find candidate category and value columns
+        guard let (categoryCol, valueCol) = findCategoryValuePair(in: table) else {
+            return nil
+        }
+
+        let chartType = recommendChartType(
+            table: table,
+            categoryColumn: categoryCol,
+            valueColumn: valueCol
+        )
+
+        let confidence = computeConfidence(
+            table: table,
+            categoryColumn: categoryCol,
+            valueColumn: valueCol,
+            chartType: chartType
+        )
+
+        let reason = describeReason(
+            chartType: chartType,
+            categoryColumn: categoryCol,
+            valueColumn: valueCol,
+            table: table
+        )
+
+        return ChartRecommendation(
+            chartType: chartType,
+            categoryColumn: categoryCol.name,
+            valueColumn: valueCol.name,
+            confidence: confidence,
+            reason: reason
+        )
+    }
+
+    /// Returns all viable chart recommendations, ranked by confidence.
+    ///
+    /// - Parameter table: The data table to analyze.
+    /// - Returns: An array of recommendations sorted by confidence (highest first).
+    public func allRecommendations(for table: DataTable) -> [ChartRecommendation] {
+        guard table.columnCount >= 2,
+              table.rowCount >= minimumRows,
+              table.rowCount <= maximumRows else {
+            return []
+        }
+
+        guard let (categoryCol, valueCol) = findCategoryValuePair(in: table) else {
+            return []
+        }
+
+        return ChartType.allCases.compactMap { chartType in
+            guard isViable(chartType, table: table, categoryColumn: categoryCol) else {
+                return nil
+            }
+
+            let confidence = computeConfidence(
+                table: table,
+                categoryColumn: categoryCol,
+                valueColumn: valueCol,
+                chartType: chartType
+            )
+
+            let reason = describeReason(
+                chartType: chartType,
+                categoryColumn: categoryCol,
+                valueColumn: valueCol,
+                table: table
+            )
+
+            return ChartRecommendation(
+                chartType: chartType,
+                categoryColumn: categoryCol.name,
+                valueColumn: valueCol.name,
+                confidence: confidence,
+                reason: reason
+            )
+        }
+        .sorted { $0.confidence > $1.confidence }
+    }
+
+    // MARK: - Private Helpers
+
+    /// Finds the best (category, value) column pair from the table.
+    private func findCategoryValuePair(
+        in table: DataTable
+    ) -> (category: DataTable.Column, value: DataTable.Column)? {
+        let numericColumns = table.columns.filter { isNumeric($0) }
+        let categoryColumns = table.columns.filter { isCategory($0) }
+
+        // Prefer: first text/category column + first numeric column
+        if let cat = categoryColumns.first, let val = numericColumns.first {
+            return (cat, val)
+        }
+
+        // Fallback: if all columns are numeric, use first as category, second as value
+        if numericColumns.count >= 2 {
+            return (numericColumns[0], numericColumns[1])
+        }
+
+        return nil
+    }
+
+    /// Recommends the single best chart type for the data shape.
+    private func recommendChartType(
+        table: DataTable,
+        categoryColumn: DataTable.Column,
+        valueColumn: DataTable.Column
+    ) -> ChartType {
+        // Line: time series or sequential numeric categories (check first — strongest signal)
+        if isTimeSeries(categoryColumn, in: table) || isSequential(categoryColumn, in: table) {
+            return .line
+        }
+
+        // Pie: small number of categories with all-positive values
+        // Only when clearly categorical (text labels) and few rows
+        if table.rowCount <= maxPieSlices,
+           isCategory(categoryColumn),
+           isPieCandidate(table: table, valueColumn: valueColumn),
+           looksProportional(table: table, valueColumn: valueColumn) {
+            return .pie
+        }
+
+        // Default: bar chart for categorical comparisons
+        return .bar
+    }
+
+    /// Checks if a chart type is viable for the given data.
+    private func isViable(
+        _ chartType: ChartType,
+        table: DataTable,
+        categoryColumn: DataTable.Column
+    ) -> Bool {
+        switch chartType {
+        case .pie:
+            return table.rowCount <= maxPieSlices
+        case .line:
+            return table.rowCount >= minimumRows
+        case .bar:
+            return true
+        }
+    }
+
+    /// Determines if a column holds numeric data.
+    private func isNumeric(_ column: DataTable.Column) -> Bool {
+        switch column.inferredType {
+        case .integer, .real:
+            return true
+        default:
+            return false
+        }
+    }
+
+    /// Determines if a column holds categorical (label) data.
+    private func isCategory(_ column: DataTable.Column) -> Bool {
+        switch column.inferredType {
+        case .text, .mixed:
+            return true
+        default:
+            return false
+        }
+    }
+
+    /// Checks if the value column contains all non-negative values,
+    /// making it a candidate for pie charts.
+    private func isPieCandidate(
+        table: DataTable,
+        valueColumn: DataTable.Column
+    ) -> Bool {
+        let values = table.numericValues(forColumn: valueColumn.name)
+        guard !values.isEmpty else { return false }
+        // All values must be positive for a meaningful pie chart
+        return values.allSatisfy { $0 > 0 }
+    }
+
+    /// Heuristic: do values look like they represent parts of a whole?
+    ///
+    /// Checks for aggregate-like column names (count, total, sum, amount, pct, etc.)
+    /// or if values sum to a round number suggesting percentages/proportions.
+    private func looksProportional(
+        table: DataTable,
+        valueColumn: DataTable.Column
+    ) -> Bool {
+        let proportionalNames: Set<String> = ["count", "total", "sum", "amount", "pct",
+                                               "percent", "percentage", "share", "proportion",
+                                               "quantity", "qty", "num", "number"]
+        // Split on common separators and check for exact word matches
+        let lowerName = valueColumn.name.lowercased()
+        let words = Set(lowerName.split { $0 == "_" || $0 == "-" || $0 == " " }.map(String.init))
+        if !words.isDisjoint(with: proportionalNames) {
+            return true
+        }
+
+        // Check if values sum to ~100 (percentages)
+        let values = table.numericValues(forColumn: valueColumn.name)
+        let sum = values.reduce(0, +)
+        if abs(sum - 100.0) < 1.0 {
+            return true
+        }
+
+        return false
+    }
+
+    /// Heuristic: does the category column look like time-series data?
+    ///
+    /// Checks for date-like patterns (YYYY, YYYY-MM, YYYY-MM-DD)
+    /// or common time-related column names.
+    private func isTimeSeries(_ column: DataTable.Column, in table: DataTable) -> Bool {
+        let timeNames = ["date", "time", "timestamp", "year", "month", "day",
+                         "week", "quarter", "period", "created_at", "updated_at"]
+        let lowerName = column.name.lowercased()
+        if timeNames.contains(where: { lowerName.contains($0) }) {
+            return true
+        }
+
+        // Check if text values look like dates
+        if column.inferredType == .text {
+            let values = table.stringValues(forColumn: column.name)
+            let datePattern = #/^\d{4}(-\d{2}){0,2}$/#
+            let matchCount = values.prefix(5).filter { (try? datePattern.wholeMatch(in: $0)) != nil }.count
+            if matchCount >= 3 {
+                return true
+            }
+        }
+
+        return false
+    }
+
+    /// Heuristic: does the category column contain sequential numeric values?
+    private func isSequential(_ column: DataTable.Column, in table: DataTable) -> Bool {
+        guard isNumeric(column) else { return false }
+        let values = table.numericValues(forColumn: column.name)
+        guard values.count >= 3 else { return false }
+
+        // Check if values are monotonically increasing
+        for i in 1..<values.count {
+            if values[i] <= values[i - 1] {
+                return false
+            }
+        }
+        return true
+    }
+
+    /// Computes a confidence score for a specific chart type + data combination.
+    private func computeConfidence(
+        table: DataTable,
+        categoryColumn: DataTable.Column,
+        valueColumn: DataTable.Column,
+        chartType: ChartType
+    ) -> Double {
+        var score = 0.5 // baseline
+
+        // Bonus: clear category/value split (text + numeric)
+        if isCategory(categoryColumn) && isNumeric(valueColumn) {
+            score += 0.2
+        }
+
+        // Bonus: reasonable row count for the chart type
+        switch chartType {
+        case .bar:
+            if table.rowCount >= 2 && table.rowCount <= 20 {
+                score += 0.15
+            }
+        case .line:
+            if isTimeSeries(categoryColumn, in: table) {
+                score += 0.2
+            } else if isSequential(categoryColumn, in: table) {
+                score += 0.1
+            }
+        case .pie:
+            if table.rowCount <= maxPieSlices && isPieCandidate(table: table, valueColumn: valueColumn) {
+                score += 0.2
+            }
+            // Penalty: too many slices
+            if table.rowCount > 5 {
+                score -= 0.1
+            }
+        }
+
+        // Bonus: no null values in key columns
+        let categoryNulls = table.columnValues(named: categoryColumn.name).filter(\.isNull).count
+        let valueNulls = table.columnValues(named: valueColumn.name).filter(\.isNull).count
+        if categoryNulls == 0 && valueNulls == 0 {
+            score += 0.1
+        }
+
+        return min(max(score, 0.0), 1.0)
+    }
+
+    /// Generates a human-readable reason for the recommendation.
+    private func describeReason(
+        chartType: ChartType,
+        categoryColumn: DataTable.Column,
+        valueColumn: DataTable.Column,
+        table: DataTable
+    ) -> String {
+        switch chartType {
+        case .bar:
+            return "\(table.rowCount) categories comparing \(valueColumn.name) by \(categoryColumn.name)"
+        case .line:
+            if isTimeSeries(categoryColumn, in: table) {
+                return "\(valueColumn.name) over time (\(categoryColumn.name))"
+            }
+            return "\(valueColumn.name) trend across \(table.rowCount) points"
+        case .pie:
+            return "Proportional breakdown of \(valueColumn.name) by \(categoryColumn.name)"
+        }
+    }
+}

Sources/SwiftDBAI/Rendering/DataTable.swift

@@ -0,0 +1,255 @@
+// DataTable.swift
+// SwiftDBAI
+//
+// Structured table representation for rendering query results
+// in SwiftUI table views and charts.
+
+import Foundation
+
+/// A structured, row-column table built from a `QueryResult`.
+///
+/// `DataTable` provides indexed access to rows and columns, typed column
+/// metadata, and convenience methods for extracting data suitable for
+/// SwiftUI `Table` views and Swift Charts.
+///
+/// Usage:
+/// ```swift
+/// let table = DataTable(queryResult)
+/// print(table.columnCount) // 3
+/// print(table[row: 0, column: 1]) // .text("Alice")
+/// ```
+public struct DataTable: Sendable, Equatable {
+
+    // MARK: - Column Metadata
+
+    /// Metadata for a single column in the data table.
+    public struct Column: Sendable, Equatable, Identifiable {
+        /// Stable identifier for the column (same as `name`).
+        public var id: String { name }
+
+        /// Column name from the query result set.
+        public let name: String
+
+        /// Index of this column in the table (0-based).
+        public let index: Int
+
+        /// Inferred data type based on the values in this column.
+        public let inferredType: InferredType
+
+        public init(name: String, index: Int, inferredType: InferredType) {
+            self.name = name
+            self.index = index
+            self.inferredType = inferredType
+        }
+    }
+
+    /// The inferred data type for a column, determined by inspecting its values.
+    public enum InferredType: Sendable, Equatable {
+        /// All non-null values are integers.
+        case integer
+        /// All non-null values are numeric (mix of integer and real).
+        case real
+        /// All non-null values are text.
+        case text
+        /// Values contain blob data.
+        case blob
+        /// Column contains only null values or is empty.
+        case null
+        /// Values are a mix of incompatible types.
+        case mixed
+    }
+
+    // MARK: - Row Type
+
+    /// A single row in the data table, providing indexed and named access.
+    public struct Row: Sendable, Equatable, Identifiable {
+        /// Row index (0-based), used as stable identity.
+        public let id: Int
+
+        /// Values in column order.
+        public let values: [QueryResult.Value]
+
+        /// Column names for named access.
+        private let columnNames: [String]
+
+        public init(id: Int, values: [QueryResult.Value], columnNames: [String]) {
+            self.id = id
+            self.values = values
+            self.columnNames = columnNames
+        }
+
+        /// Access a value by column index.
+        public subscript(columnIndex: Int) -> QueryResult.Value {
+            values[columnIndex]
+        }
+
+        /// Access a value by column name. Returns `.null` if the column doesn't exist.
+        public subscript(columnName: String) -> QueryResult.Value {
+            guard let idx = columnNames.firstIndex(of: columnName) else {
+                return .null
+            }
+            return values[idx]
+        }
+    }
+
+    // MARK: - Properties
+
+    /// Column metadata in order.
+    public let columns: [Column]
+
+    /// All rows in order.
+    public let rows: [Row]
+
+    /// The SQL that produced this table.
+    public let sql: String
+
+    /// Execution time of the underlying query.
+    public let executionTime: TimeInterval
+
+    /// Number of columns.
+    public var columnCount: Int { columns.count }
+
+    /// Number of rows.
+    public var rowCount: Int { rows.count }
+
+    /// Whether the table has no rows.
+    public var isEmpty: Bool { rows.isEmpty }
+
+    /// Column names in order.
+    public var columnNames: [String] { columns.map(\.name) }
+
+    // MARK: - Initialization
+
+    /// Creates a `DataTable` from a `QueryResult`.
+    ///
+    /// Converts the dictionary-based row representation into an indexed
+    /// array representation and infers column types from the data.
+    ///
+    /// - Parameter queryResult: The raw query result to convert.
+    public init(_ queryResult: QueryResult) {
+        let colNames = queryResult.columns
+
+        // Build indexed rows
+        let indexedRows: [Row] = queryResult.rows.enumerated().map { idx, rowDict in
+            let values = colNames.map { col in
+                rowDict[col] ?? .null
+            }
+            return Row(id: idx, values: values, columnNames: colNames)
+        }
+
+        // Infer column types
+        let inferredColumns: [Column] = colNames.enumerated().map { colIdx, name in
+            let type = Self.inferType(
+                from: indexedRows.map { $0.values[colIdx] }
+            )
+            return Column(name: name, index: colIdx, inferredType: type)
+        }
+
+        self.columns = inferredColumns
+        self.rows = indexedRows
+        self.sql = queryResult.sql
+        self.executionTime = queryResult.executionTime
+    }
+
+    /// Creates a `DataTable` directly from components (useful for testing).
+    public init(
+        columns: [Column],
+        rows: [Row],
+        sql: String = "",
+        executionTime: TimeInterval = 0
+    ) {
+        self.columns = columns
+        self.rows = rows
+        self.sql = sql
+        self.executionTime = executionTime
+    }
+
+    // MARK: - Subscript Access
+
+    /// Access a cell by row and column index.
+    public subscript(row rowIndex: Int, column columnIndex: Int) -> QueryResult.Value {
+        rows[rowIndex].values[columnIndex]
+    }
+
+    /// Access a cell by row index and column name.
+    public subscript(row rowIndex: Int, column columnName: String) -> QueryResult.Value {
+        rows[rowIndex][columnName]
+    }
+
+    // MARK: - Column Data Extraction
+
+    /// Returns all values for a column by index, in row order.
+    public func columnValues(at index: Int) -> [QueryResult.Value] {
+        rows.map { $0.values[index] }
+    }
+
+    /// Returns all values for a column by name, in row order.
+    public func columnValues(named name: String) -> [QueryResult.Value] {
+        guard let col = columns.first(where: { $0.name == name }) else {
+            return []
+        }
+        return columnValues(at: col.index)
+    }
+
+    /// Returns all non-null `Double` values for a column (useful for charting).
+    public func numericValues(forColumn name: String) -> [Double] {
+        columnValues(named: name).compactMap(\.doubleValue)
+    }
+
+    /// Returns all non-null `String` values for a column (useful for labels).
+    public func stringValues(forColumn name: String) -> [String] {
+        columnValues(named: name).compactMap { value in
+            if case .null = value { return nil }
+            return value.stringValue
+        }
+    }
+
+    // MARK: - Type Inference
+
+    /// Infers the predominant type from an array of values.
+    static func inferType(from values: [QueryResult.Value]) -> InferredType {
+        var hasInteger = false
+        var hasReal = false
+        var hasText = false
+        var hasBlob = false
+        var hasNonNull = false
+
+        for value in values {
+            switch value {
+            case .integer:
+                hasInteger = true
+                hasNonNull = true
+            case .real:
+                hasReal = true
+                hasNonNull = true
+            case .text:
+                hasText = true
+                hasNonNull = true
+            case .blob:
+                hasBlob = true
+                hasNonNull = true
+            case .null:
+                break
+            }
+        }
+
+        guard hasNonNull else { return .null }
+
+        // Count how many distinct types are present
+        let typeCount = [hasInteger, hasReal, hasText, hasBlob].filter { $0 }.count
+
+        if typeCount == 1 {
+            if hasInteger { return .integer }
+            if hasReal { return .real }
+            if hasText { return .text }
+            if hasBlob { return .blob }
+        }
+
+        // Integer + real → treat as real (numeric promotion)
+        if typeCount == 2, hasInteger, hasReal {
+            return .real
+        }
+
+        return .mixed
+    }
+}

Sources/SwiftDBAI/Rendering/TextSummaryRenderer.swift

@@ -0,0 +1,301 @@
+// TextSummaryRenderer.swift
+// SwiftDBAI
+//
+// Converts raw SQL query results into natural language text summaries
+// using the LLM via AnyLanguageModel.
+
+import AnyLanguageModel
+import Foundation
+
+/// Renders SQL query results as natural language text summaries.
+///
+/// The renderer takes a `QueryResult` and the user's original question,
+/// sends them to the LLM for summarization, and returns a concise,
+/// human-readable response.
+///
+/// Usage:
+/// ```swift
+/// let renderer = TextSummaryRenderer(model: myModel)
+/// let summary = try await renderer.summarize(
+///     result: queryResult,
+///     userQuestion: "How many orders were placed last month?"
+/// )
+/// print(summary) // "There were 42 orders placed last month."
+/// ```
+public struct TextSummaryRenderer: Sendable {
+
+    /// The language model used to generate summaries.
+    private let model: any LanguageModel
+
+    /// Maximum number of rows to include in the LLM prompt.
+    ///
+    /// Results larger than this are truncated with a note about total count.
+    public let maxRowsInPrompt: Int
+
+    /// Creates a new text summary renderer.
+    ///
+    /// - Parameters:
+    ///   - model: Any `AnyLanguageModel`-compatible language model.
+    ///   - maxRowsInPrompt: Maximum rows to send to the LLM for summarization (default: 50).
+    public init(model: any LanguageModel, maxRowsInPrompt: Int = 50) {
+        self.model = model
+        self.maxRowsInPrompt = maxRowsInPrompt
+    }
+
+    /// Generates a natural language summary of query results.
+    ///
+    /// - Parameters:
+    ///   - result: The raw `QueryResult` from SQL execution.
+    ///   - userQuestion: The original natural language question from the user.
+    ///   - context: Optional additional context (e.g., table descriptions) to help the LLM.
+    /// - Returns: A natural language text summary of the results.
+    public func summarize(
+        result: QueryResult,
+        userQuestion: String,
+        context: String? = nil
+    ) async throws -> String {
+        // For mutation results (INSERT/UPDATE/DELETE), use a simple template
+        if let affected = result.rowsAffected {
+            return summarizeMutation(result: result, affected: affected)
+        }
+
+        // For empty results, no need to call the LLM
+        if result.rows.isEmpty {
+            return "No results found for your query."
+        }
+
+        // For simple aggregates, produce a direct answer without LLM
+        if let directAnswer = tryDirectAggregateSummary(result: result, userQuestion: userQuestion) {
+            return directAnswer
+        }
+
+        // Build the prompt and ask the LLM to summarize
+        let prompt = buildSummarizationPrompt(
+            result: result,
+            userQuestion: userQuestion,
+            context: context
+        )
+
+        let session = LanguageModelSession(
+            model: model,
+            instructions: summaryInstructions
+        )
+
+        let response = try await session.respond(to: prompt)
+        return response.content.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    /// Generates a summary without calling the LLM, using simple templates.
+    ///
+    /// Useful when LLM access is unavailable, or for fast local rendering.
+    ///
+    /// - Parameters:
+    ///   - result: The raw `QueryResult` from SQL execution.
+    ///   - userQuestion: The original natural language question.
+    /// - Returns: A template-based text summary.
+    public func localSummary(result: QueryResult, userQuestion: String) -> String {
+        if let affected = result.rowsAffected {
+            return summarizeMutation(result: result, affected: affected)
+        }
+
+        if result.rows.isEmpty {
+            return "No results found for your query."
+        }
+
+        if let directAnswer = tryDirectAggregateSummary(result: result, userQuestion: userQuestion) {
+            return directAnswer
+        }
+
+        return buildTemplateSummary(result: result)
+    }
+
+    // MARK: - Private Helpers
+
+    /// System instructions for the summarization session.
+    private var summaryInstructions: String {
+        """
+        You are a data assistant that summarizes SQL query results in natural language.
+
+        Rules:
+        - Be concise and direct. Answer the user's question first, then add detail if helpful.
+        - Use natural language, not SQL or code.
+        - For numeric results, include the exact numbers.
+        - For lists of records, summarize the count and highlight notable items.
+        - If the data contains dates, format them in a readable way.
+        - Do not mention SQL, databases, tables, columns, or queries in your response.
+        - Do not include markdown formatting.
+        - Keep your response under 3 sentences for simple results, under 5 for complex ones.
+        """
+    }
+
+    /// Builds the prompt sent to the LLM for summarization.
+    private func buildSummarizationPrompt(
+        result: QueryResult,
+        userQuestion: String,
+        context: String?
+    ) -> String {
+        var parts: [String] = []
+
+        parts.append("User's question: \(userQuestion)")
+
+        if let context {
+            parts.append("Context: \(context)")
+        }
+
+        parts.append("Query returned \(result.rowCount) row(s) with columns: \(result.columns.joined(separator: ", "))")
+
+        // Include the result data (truncated if large)
+        let dataStr = formatResultData(result)
+        parts.append("Data:\n\(dataStr)")
+
+        parts.append("Summarize these results in natural language, directly answering the user's question.")
+
+        return parts.joined(separator: "\n\n")
+    }
+
+    /// Formats the query result data as a compact table for the LLM prompt.
+    private func formatResultData(_ result: QueryResult) -> String {
+        let rowsToInclude = Array(result.rows.prefix(maxRowsInPrompt))
+        var lines: [String] = []
+
+        // Header
+        lines.append(result.columns.joined(separator: " | "))
+
+        // Rows
+        for row in rowsToInclude {
+            let values = result.columns.map { col in
+                row[col]?.description ?? "NULL"
+            }
+            lines.append(values.joined(separator: " | "))
+        }
+
+        if result.rowCount > maxRowsInPrompt {
+            lines.append("(\(result.rowCount - maxRowsInPrompt) additional rows not shown)")
+        }
+
+        return lines.joined(separator: "\n")
+    }
+
+    /// Produces a direct answer for simple aggregate queries (1 row, few columns).
+    private func tryDirectAggregateSummary(result: QueryResult, userQuestion: String) -> String? {
+        guard result.isAggregate else { return nil }
+
+        let row = result.rows[0]
+
+        // Single numeric column — e.g., "COUNT(*)" → "42"
+        if result.columns.count == 1 {
+            let col = result.columns[0]
+            guard let value = row[col] else { return nil }
+            let formatted = formatNumber(value)
+            return "The result is \(formatted)."
+        }
+
+        // Multiple aggregate columns — e.g., COUNT, AVG, SUM
+        let parts = result.columns.compactMap { col -> String? in
+            guard let value = row[col] else { return nil }
+            let label = humanizeColumnName(col)
+            let formatted = formatNumber(value)
+            return "\(label): \(formatted)"
+        }
+        return parts.joined(separator: ", ") + "."
+    }
+
+    /// Formats a numeric Value for display.
+    private func formatNumber(_ value: QueryResult.Value) -> String {
+        switch value {
+        case .integer(let i):
+            return NumberFormatter.localizedString(from: NSNumber(value: i), number: .decimal)
+        case .real(let d):
+            if d == d.rounded() && abs(d) < 1e12 {
+                return NumberFormatter.localizedString(from: NSNumber(value: Int64(d)), number: .decimal)
+            }
+            let formatter = NumberFormatter()
+            formatter.numberStyle = .decimal
+            formatter.maximumFractionDigits = 2
+            return formatter.string(from: NSNumber(value: d)) ?? String(d)
+        default:
+            return value.description
+        }
+    }
+
+    /// Converts a column name like "total_count" or "AVG(price)" into a readable label.
+    private func humanizeColumnName(_ name: String) -> String {
+        // Handle SQL function names: "COUNT(*)" → "count", "AVG(price)" → "average price"
+        let functionPatterns: [(pattern: String, label: String)] = [
+            ("COUNT", "count"),
+            ("SUM", "total"),
+            ("AVG", "average"),
+            ("MIN", "minimum"),
+            ("MAX", "maximum"),
+        ]
+
+        let upper = name.uppercased()
+        for (pattern, label) in functionPatterns {
+            if upper.hasPrefix(pattern + "(") {
+                // Extract the inner column name
+                let start = name.index(name.startIndex, offsetBy: pattern.count + 1)
+                let end = name.index(before: name.endIndex)
+                if start < end {
+                    let inner = String(name[start..<end])
+                    if inner == "*" { return label }
+                    return "\(label) \(humanizeColumnName(inner))"
+                }
+                return label
+            }
+        }
+
+        // snake_case → space-separated
+        return name
+            .replacingOccurrences(of: "_", with: " ")
+            .lowercased()
+    }
+
+    /// Produces a template-based summary without calling the LLM.
+    private func buildTemplateSummary(result: QueryResult) -> String {
+        let count = result.rowCount
+
+        if count == 1 {
+            // Single record — list field values
+            let row = result.rows[0]
+            let details = result.columns.prefix(5).compactMap { col -> String? in
+                guard let val = row[col], !val.isNull else { return nil }
+                return "\(humanizeColumnName(col)): \(val.description)"
+            }
+            return "Found 1 result. \(details.joined(separator: ", "))."
+        }
+
+        // Multiple records
+        var summary = "Found \(count) results"
+
+        // If there's a clear "name" or "title" column, list first few
+        let nameColumns = ["name", "title", "label", "description"]
+        if let nameCol = result.columns.first(where: { nameColumns.contains($0.lowercased()) }) {
+            let names = result.rows.prefix(3).compactMap { $0[nameCol]?.description }
+            if !names.isEmpty {
+                summary += " including \(names.joined(separator: ", "))"
+                if count > 3 { summary += ", and \(count - 3) more" }
+            }
+        }
+
+        return summary + "."
+    }
+
+    /// Summarizes a mutation (INSERT/UPDATE/DELETE) result.
+    private func summarizeMutation(result: QueryResult, affected: Int) -> String {
+        let sql = result.sql.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
+
+        let operation: String
+        if sql.hasPrefix("INSERT") {
+            operation = "inserted"
+        } else if sql.hasPrefix("UPDATE") {
+            operation = "updated"
+        } else if sql.hasPrefix("DELETE") {
+            operation = "deleted"
+        } else {
+            operation = "affected"
+        }
+
+        let noun = affected == 1 ? "row" : "rows"
+        return "Successfully \(operation) \(affected) \(noun)."
+    }
+}

Sources/SwiftDBAI/Schema/DatabaseSchema.swift

@@ -0,0 +1,164 @@
+// DatabaseSchema.swift
+// SwiftDBAI
+//
+// Auto-introspected SQLite schema model types.
+
+import Foundation
+
+/// Complete schema representation of an SQLite database.
+public struct DatabaseSchema: Sendable, Equatable {
+    /// All tables in the database, keyed by table name.
+    public let tables: [String: TableSchema]
+
+    /// Ordered table names (preserves discovery order).
+    public let tableNames: [String]
+
+    /// Returns a compact text description suitable for LLM system prompts.
+    public var schemaDescription: String {
+        var lines: [String] = []
+        for name in tableNames {
+            guard let table = tables[name] else { continue }
+            lines.append(table.descriptionForLLM)
+        }
+        return lines.joined(separator: "\n\n")
+    }
+
+    /// Returns a description suitable for LLM system prompts.
+    /// Alias for `schemaDescription` for API compatibility.
+    public func describeForLLM() -> String {
+        schemaDescription
+    }
+
+    public init(tables: [String: TableSchema], tableNames: [String]) {
+        self.tables = tables
+        self.tableNames = tableNames
+    }
+}
+
+/// Schema for a single SQLite table.
+public struct TableSchema: Sendable, Equatable {
+    public let name: String
+    public let columns: [ColumnSchema]
+    public let primaryKey: [String]
+    public let foreignKeys: [ForeignKeySchema]
+    public let indexes: [IndexSchema]
+
+    /// Text description for embedding in LLM prompts.
+    public var descriptionForLLM: String {
+        var parts: [String] = []
+        let colDefs = columns.map { col in
+            var def = "  \(col.name) \(col.type)"
+            if col.isPrimaryKey { def += " PRIMARY KEY" }
+            if col.isNotNull { def += " NOT NULL" }
+            if let defaultValue = col.defaultValue { def += " DEFAULT \(defaultValue)" }
+            return def
+        }
+        parts.append("TABLE \(name) (\n\(colDefs.joined(separator: ",\n"))\n)")
+
+        if !foreignKeys.isEmpty {
+            let fkDescs = foreignKeys.map {
+                "  FOREIGN KEY (\($0.fromColumn)) REFERENCES \($0.toTable)(\($0.toColumn))"
+            }
+            parts.append("FOREIGN KEYS:\n\(fkDescs.joined(separator: "\n"))")
+        }
+
+        if !indexes.isEmpty {
+            let idxDescs = indexes.map {
+                "  INDEX \($0.name) ON (\($0.columns.joined(separator: ", ")))\($0.isUnique ? " UNIQUE" : "")"
+            }
+            parts.append("INDEXES:\n\(idxDescs.joined(separator: "\n"))")
+        }
+
+        return parts.joined(separator: "\n")
+    }
+
+    public init(
+        name: String,
+        columns: [ColumnSchema],
+        primaryKey: [String],
+        foreignKeys: [ForeignKeySchema],
+        indexes: [IndexSchema]
+    ) {
+        self.name = name
+        self.columns = columns
+        self.primaryKey = primaryKey
+        self.foreignKeys = foreignKeys
+        self.indexes = indexes
+    }
+}
+
+/// Schema for a single column.
+public struct ColumnSchema: Sendable, Equatable {
+    /// Column position (0-based).
+    public let cid: Int
+    /// Column name.
+    public let name: String
+    /// Declared SQLite type (e.g. "TEXT", "INTEGER", "REAL", "BLOB").
+    public let type: String
+    /// Whether the column has a NOT NULL constraint.
+    public let isNotNull: Bool
+    /// Default value expression, if any.
+    public let defaultValue: String?
+    /// Whether this column is part of the primary key.
+    public let isPrimaryKey: Bool
+
+    public init(
+        cid: Int,
+        name: String,
+        type: String,
+        isNotNull: Bool,
+        defaultValue: String?,
+        isPrimaryKey: Bool
+    ) {
+        self.cid = cid
+        self.name = name
+        self.type = type
+        self.isNotNull = isNotNull
+        self.defaultValue = defaultValue
+        self.isPrimaryKey = isPrimaryKey
+    }
+}
+
+/// Schema for a foreign key relationship.
+public struct ForeignKeySchema: Sendable, Equatable {
+    /// Column in the source table.
+    public let fromColumn: String
+    /// Referenced table name.
+    public let toTable: String
+    /// Referenced column name.
+    public let toColumn: String
+    /// ON UPDATE action (e.g. "CASCADE", "NO ACTION").
+    public let onUpdate: String
+    /// ON DELETE action.
+    public let onDelete: String
+
+    public init(
+        fromColumn: String,
+        toTable: String,
+        toColumn: String,
+        onUpdate: String,
+        onDelete: String
+    ) {
+        self.fromColumn = fromColumn
+        self.toTable = toTable
+        self.toColumn = toColumn
+        self.onUpdate = onUpdate
+        self.onDelete = onDelete
+    }
+}
+
+/// Schema for a database index.
+public struct IndexSchema: Sendable, Equatable {
+    /// Index name.
+    public let name: String
+    /// Whether the index enforces uniqueness.
+    public let isUnique: Bool
+    /// Columns included in the index, in order.
+    public let columns: [String]
+
+    public init(name: String, isUnique: Bool, columns: [String]) {
+        self.name = name
+        self.isUnique = isUnique
+        self.columns = columns
+    }
+}

Sources/SwiftDBAI/Schema/SchemaIntrospector.swift

@@ -0,0 +1,153 @@
+// SchemaIntrospector.swift
+// SwiftDBAI
+//
+// Auto-introspects SQLite database schema using GRDB.
+
+import GRDB
+
+/// Introspects an SQLite database schema by querying sqlite_master and PRAGMA statements.
+///
+/// Usage:
+/// ```swift
+/// let dbPool = try DatabasePool(path: "path/to/db.sqlite")
+/// let schema = try await SchemaIntrospector.introspect(database: dbPool)
+/// print(schema.schemaDescription)
+/// ```
+public struct SchemaIntrospector: Sendable {
+
+    // MARK: - Public API
+
+    /// Introspects the full schema of the given database.
+    ///
+    /// Discovers all user tables (excluding sqlite_ internal tables),
+    /// their columns, primary keys, foreign keys, and indexes.
+    ///
+    /// - Parameter database: A GRDB `DatabaseReader` (DatabasePool or DatabaseQueue).
+    /// - Returns: A complete `DatabaseSchema` representation.
+    public static func introspect(database: any DatabaseReader) async throws -> DatabaseSchema {
+        try await database.read { db in
+            try introspect(db: db)
+        }
+    }
+
+    /// Synchronous introspection within an existing database access context.
+    ///
+    /// - Parameter db: A GRDB `Database` instance from within a read/write block.
+    /// - Returns: A complete `DatabaseSchema` representation.
+    public static func introspect(db: Database) throws -> DatabaseSchema {
+        let tableNames = try fetchTableNames(db: db)
+        var tables: [String: TableSchema] = [:]
+
+        for tableName in tableNames {
+            let columns = try fetchColumns(db: db, table: tableName)
+            let primaryKey = try fetchPrimaryKey(db: db, table: tableName)
+            let foreignKeys = try fetchForeignKeys(db: db, table: tableName)
+            let indexes = try fetchIndexes(db: db, table: tableName)
+
+            // Mark columns that are part of the primary key
+            let pkSet = Set(primaryKey)
+            let annotatedColumns = columns.map { col in
+                ColumnSchema(
+                    cid: col.cid,
+                    name: col.name,
+                    type: col.type,
+                    isNotNull: col.isNotNull,
+                    defaultValue: col.defaultValue,
+                    isPrimaryKey: pkSet.contains(col.name)
+                )
+            }
+
+            tables[tableName] = TableSchema(
+                name: tableName,
+                columns: annotatedColumns,
+                primaryKey: primaryKey,
+                foreignKeys: foreignKeys,
+                indexes: indexes
+            )
+        }
+
+        return DatabaseSchema(tables: tables, tableNames: tableNames)
+    }
+
+    // MARK: - Private Helpers
+
+    /// Fetches all user table names from sqlite_master.
+    private static func fetchTableNames(db: Database) throws -> [String] {
+        let sql = """
+            SELECT name FROM sqlite_master
+            WHERE type = 'table'
+            AND name NOT LIKE 'sqlite_%'
+            ORDER BY name
+            """
+        return try String.fetchAll(db, sql: sql)
+    }
+
+    /// Fetches column metadata for a table using PRAGMA table_info.
+    private static func fetchColumns(db: Database, table: String) throws -> [ColumnSchema] {
+        let sql = "PRAGMA table_info(\(table.quotedDatabaseIdentifier))"
+        let rows = try Row.fetchAll(db, sql: sql)
+        return rows.map { row in
+            ColumnSchema(
+                cid: row["cid"],
+                name: row["name"],
+                type: (row["type"] as String?) ?? "",
+                isNotNull: row["notnull"] == 1,
+                defaultValue: row["dflt_value"],
+                isPrimaryKey: row["pk"] != 0
+            )
+        }
+    }
+
+    /// Fetches primary key columns for a table.
+    private static func fetchPrimaryKey(db: Database, table: String) throws -> [String] {
+        let sql = "PRAGMA table_info(\(table.quotedDatabaseIdentifier))"
+        let rows = try Row.fetchAll(db, sql: sql)
+        return rows
+            .filter { ($0["pk"] as Int) > 0 }
+            .sorted { ($0["pk"] as Int) < ($1["pk"] as Int) }
+            .map { $0["name"] }
+    }
+
+    /// Fetches foreign key relationships for a table.
+    private static func fetchForeignKeys(db: Database, table: String) throws -> [ForeignKeySchema] {
+        let sql = "PRAGMA foreign_key_list(\(table.quotedDatabaseIdentifier))"
+        let rows = try Row.fetchAll(db, sql: sql)
+        return rows.map { row in
+            ForeignKeySchema(
+                fromColumn: row["from"],
+                toTable: row["table"],
+                toColumn: row["to"],
+                onUpdate: row["on_update"] ?? "NO ACTION",
+                onDelete: row["on_delete"] ?? "NO ACTION"
+            )
+        }
+    }
+
+    /// Fetches indexes and their columns for a table.
+    private static func fetchIndexes(db: Database, table: String) throws -> [IndexSchema] {
+        let indexListSQL = "PRAGMA index_list(\(table.quotedDatabaseIdentifier))"
+        let indexRows = try Row.fetchAll(db, sql: indexListSQL)
+
+        var indexes: [IndexSchema] = []
+        for indexRow in indexRows {
+            let indexName: String = indexRow["name"]
+            let isUnique: Bool = indexRow["unique"] == 1
+
+            // Skip auto-generated indexes for primary keys
+            if indexName.hasPrefix("sqlite_autoindex_") { continue }
+
+            let infoSQL = "PRAGMA index_info(\(indexName.quotedDatabaseIdentifier))"
+            let infoRows = try Row.fetchAll(db, sql: infoSQL)
+            let columns: [String] = infoRows
+                .sorted { ($0["seqno"] as Int) < ($1["seqno"] as Int) }
+                .map { $0["name"] }
+
+            indexes.append(IndexSchema(
+                name: indexName,
+                isUnique: isUnique,
+                columns: columns
+            ))
+        }
+        return indexes
+    }
+}

Sources/SwiftDBAI/SwiftDBAIError.swift

@@ -0,0 +1,215 @@
+// SwiftDBAIError.swift
+// SwiftDBAI
+//
+// Unified error type for the SwiftDBAI package.
+
+import Foundation
+
+/// The top-level error type for SwiftDBAI operations.
+///
+/// `SwiftDBAIError` provides a single, typed error surface that covers
+/// every failure mode a consumer of SwiftDBAI may encounter — from invalid
+/// SQL and LLM failures to schema mismatches and safety violations.
+///
+/// Every case includes a user-friendly `localizedDescription` suitable for
+/// displaying directly in a chat interface.
+public enum SwiftDBAIError: Error, LocalizedError, Sendable, Equatable {
+
+    // MARK: - SQL Errors
+
+    /// No SQL statement could be extracted from the LLM response.
+    case noSQLGenerated
+
+    /// The generated SQL is syntactically invalid or failed execution.
+    case invalidSQL(sql: String, reason: String)
+
+    /// The SQL uses an operation (e.g. DELETE) not in the developer's allowlist.
+    case operationNotAllowed(operation: String)
+
+    /// Multiple SQL statements were generated but only single-statement execution is supported.
+    case multipleStatementsNotSupported
+
+    /// A dangerous SQL keyword (DROP, ALTER, TRUNCATE) was detected.
+    case dangerousOperationBlocked(keyword: String)
+
+    // MARK: - LLM Errors
+
+    /// The LLM failed to produce a response.
+    case llmFailure(reason: String)
+
+    /// The LLM response could not be parsed into an actionable result.
+    case llmResponseUnparseable(response: String)
+
+    /// The LLM request timed out.
+    case llmTimeout(seconds: TimeInterval)
+
+    // MARK: - Schema Errors
+
+    /// Schema introspection of the database failed.
+    case schemaIntrospectionFailed(reason: String)
+
+    /// The generated SQL references a table that does not exist in the schema.
+    case tableNotFound(tableName: String)
+
+    /// The generated SQL references a column that does not exist on the given table.
+    case columnNotFound(columnName: String, tableName: String)
+
+    /// The database schema is empty (no user tables found).
+    case emptySchema
+
+    // MARK: - Safety & Validation Errors
+
+    /// A destructive operation requires explicit user confirmation before execution.
+    case confirmationRequired(sql: String, operation: String)
+
+    /// A mutation targets a table not in the allowed mutation tables.
+    case tableNotAllowedForMutation(tableName: String, operation: String)
+
+    /// A custom query validator rejected the query.
+    case queryRejected(reason: String)
+
+    // MARK: - Database Errors
+
+    /// The underlying database operation failed.
+    case databaseError(reason: String)
+
+    /// The query exceeded the configured execution timeout.
+    case queryTimedOut(seconds: TimeInterval)
+
+    // MARK: - Configuration Errors
+
+    /// The engine has not been configured correctly.
+    case configurationError(reason: String)
+
+    // MARK: - Error Classification
+
+    /// Whether this error represents a safety/permissions issue (not a bug).
+    public var isSafetyError: Bool {
+        switch self {
+        case .operationNotAllowed, .dangerousOperationBlocked,
+             .confirmationRequired, .tableNotAllowedForMutation, .queryRejected:
+            return true
+        default:
+            return false
+        }
+    }
+
+    /// Whether this error is recoverable by rephrasing the user's question.
+    public var isRecoverable: Bool {
+        switch self {
+        case .noSQLGenerated, .llmResponseUnparseable, .invalidSQL,
+             .tableNotFound, .columnNotFound:
+            return true
+        default:
+            return false
+        }
+    }
+
+    /// Whether this error requires user action (e.g. confirmation).
+    public var requiresUserAction: Bool {
+        if case .confirmationRequired = self { return true }
+        return false
+    }
+
+    // MARK: - LocalizedError
+
+    public var errorDescription: String? {
+        switch self {
+        // SQL
+        case .noSQLGenerated:
+            return "I couldn't generate a SQL query from your request. Could you rephrase your question?"
+        case .invalidSQL(let sql, let reason):
+            return "The generated query is invalid — \(reason). Query: \(sql)"
+        case .operationNotAllowed(let operation):
+            return "The \(operation.uppercased()) operation is not allowed by the current configuration."
+        case .multipleStatementsNotSupported:
+            return "Only single SQL statements are supported. Please ask one question at a time."
+        case .dangerousOperationBlocked(let keyword):
+            return "The \(keyword.uppercased()) operation is blocked for safety. This operation is never allowed."
+
+        // LLM
+        case .llmFailure(let reason):
+            return "The language model encountered an error: \(reason)"
+        case .llmResponseUnparseable(let response):
+            return "I received a response but couldn't understand it. Raw response: \(response.prefix(200))"
+        case .llmTimeout(let seconds):
+            return "The language model did not respond within \(Int(seconds)) seconds. Please try again."
+
+        // Schema
+        case .schemaIntrospectionFailed(let reason):
+            return "Failed to read the database schema: \(reason)"
+        case .tableNotFound(let tableName):
+            return "The table '\(tableName)' does not exist in this database."
+        case .columnNotFound(let columnName, let tableName):
+            return "The column '\(columnName)' does not exist on table '\(tableName)'."
+        case .emptySchema:
+            return "This database has no tables. There's nothing to query yet."
+
+        // Safety
+        case .confirmationRequired(let sql, let operation):
+            return "The \(operation.uppercased()) operation requires your confirmation before running: \(sql)"
+        case .tableNotAllowedForMutation(let tableName, let operation):
+            return "The \(operation.uppercased()) operation is not allowed on table '\(tableName)'."
+        case .queryRejected(let reason):
+            return "Query rejected: \(reason)"
+
+        // Database
+        case .databaseError(let reason):
+            return "A database error occurred: \(reason)"
+        case .queryTimedOut(let seconds):
+            return "The query timed out after \(Int(seconds)) seconds. Try a simpler query."
+
+        // Configuration
+        case .configurationError(let reason):
+            return "Configuration error: \(reason)"
+        }
+    }
+}
+
+// MARK: - Conversion from SQLParsingError
+
+extension SQLParsingError {
+    /// Maps a ``SQLParsingError`` to the corresponding ``SwiftDBAIError`` case.
+    ///
+    /// - Parameter rawResponse: The raw LLM response text (used for context in `.noSQLFound`).
+    /// - Returns: A ``SwiftDBAIError`` with the same semantic meaning.
+    func toSwiftDBAIError(rawResponse: String = "") -> SwiftDBAIError {
+        switch self {
+        case .noSQLFound:
+            if rawResponse.isEmpty {
+                return .noSQLGenerated
+            }
+            return .llmResponseUnparseable(response: rawResponse)
+        case .operationNotAllowed(let op):
+            return .operationNotAllowed(operation: op.rawValue)
+        case .confirmationRequired(let sql, let op):
+            return .confirmationRequired(sql: sql, operation: op.rawValue)
+        case .tableNotAllowed(let table, let op):
+            return .tableNotAllowedForMutation(tableName: table, operation: op.rawValue)
+        case .dangerousOperation(let keyword):
+            return .dangerousOperationBlocked(keyword: keyword)
+        case .multipleStatements:
+            return .multipleStatementsNotSupported
+        }
+    }
+}
+
+// MARK: - Conversion from ChatEngineError
+
+extension ChatEngineError {
+    /// Maps a ``ChatEngineError`` to the corresponding ``SwiftDBAIError`` case.
+    func toSwiftDBAIError() -> SwiftDBAIError {
+        switch self {
+        case .sqlParsingFailed(let parsingError):
+            return parsingError.toSwiftDBAIError()
+        case .confirmationRequired(let sql, let operation):
+            return .confirmationRequired(sql: sql, operation: operation.rawValue)
+        case .schemaIntrospectionFailed(let reason):
+            return .schemaIntrospectionFailed(reason: reason)
+        case .queryTimedOut(let seconds):
+            return .queryTimedOut(seconds: seconds)
+        case .validationFailed(let reason):
+            return .queryRejected(reason: reason)
+        }
+    }
+}

Sources/SwiftDBAI/Views/Charts/BarChartView.swift

@@ -0,0 +1,182 @@
+// BarChartView.swift
+// SwiftDBAI
+//
+// A SwiftUI bar chart that renders DataTable values using Swift Charts.
+// Best for categorical comparisons (e.g., sales by region, counts by status).
+
+import SwiftUI
+import Charts
+
+/// A bar chart view that renders a `DataTable` column pair using Swift Charts.
+///
+/// Displays vertical bars with category labels on the x-axis and numeric
+/// values on the y-axis. Automatically colors bars using the accent gradient
+/// and supports scrolling when many categories are present.
+///
+/// Usage:
+/// ```swift
+/// BarChartView(
+///     dataTable: table,
+///     categoryColumn: "department",
+///     valueColumn: "total_sales"
+/// )
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct BarChartView: View {
+
+    /// The data to chart.
+    public let dataTable: DataTable
+
+    /// Column name for category labels (x-axis).
+    public let categoryColumn: String
+
+    /// Column name for numeric values (y-axis).
+    public let valueColumn: String
+
+    /// Optional chart title.
+    public var title: String?
+
+    /// Maximum number of bars to display before truncating.
+    public var maxBars: Int
+
+    public init(
+        dataTable: DataTable,
+        categoryColumn: String,
+        valueColumn: String,
+        title: String? = nil,
+        maxBars: Int = 30
+    ) {
+        self.dataTable = dataTable
+        self.categoryColumn = categoryColumn
+        self.valueColumn = valueColumn
+        self.title = title
+        self.maxBars = maxBars
+    }
+
+    public var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            if let title {
+                Text(title)
+                    .font(.caption.weight(.semibold))
+                    .foregroundStyle(.secondary)
+            }
+
+            if chartData.isEmpty {
+                emptyChartView
+            } else {
+                chartContent
+            }
+        }
+    }
+
+    // MARK: - Chart Content
+
+    @ViewBuilder
+    private var chartContent: some View {
+        Chart(chartData, id: \.label) { item in
+            BarMark(
+                x: .value(categoryColumn, item.label),
+                y: .value(valueColumn, item.value)
+            )
+            .foregroundStyle(
+                .linearGradient(
+                    colors: [.accentColor, .accentColor.opacity(0.7)],
+                    startPoint: .bottom,
+                    endPoint: .top
+                )
+            )
+            .cornerRadius(4)
+        }
+        .chartXAxis {
+            AxisMarks(values: .automatic) { _ in
+                AxisValueLabel()
+                    .font(.caption2)
+            }
+        }
+        .chartYAxis {
+            AxisMarks(position: .leading) { _ in
+                AxisGridLine(stroke: StrokeStyle(lineWidth: 0.5, dash: [4, 4]))
+                    .foregroundStyle(.secondary.opacity(0.3))
+                AxisValueLabel()
+                    .font(.caption2)
+            }
+        }
+        .frame(minHeight: 200)
+
+        if isTruncated {
+            truncationNotice
+        }
+    }
+
+    // MARK: - Empty State
+
+    @ViewBuilder
+    private var emptyChartView: some View {
+        VStack(spacing: 8) {
+            Image(systemName: "chart.bar")
+                .font(.title2)
+                .foregroundStyle(.secondary)
+            Text("No chartable data")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+        }
+        .frame(maxWidth: .infinity, minHeight: 100)
+    }
+
+    // MARK: - Truncation Notice
+
+    @ViewBuilder
+    private var truncationNotice: some View {
+        Text("Showing \(maxBars) of \(dataTable.rowCount) categories")
+            .font(.caption2)
+            .foregroundStyle(.secondary)
+    }
+
+    // MARK: - Data Extraction
+
+    private var isTruncated: Bool {
+        dataTable.rowCount > maxBars
+    }
+
+    private var chartData: [ChartDataPoint] {
+        let labels = dataTable.stringValues(forColumn: categoryColumn)
+        let values = dataTable.numericValues(forColumn: valueColumn)
+
+        let count = min(labels.count, values.count, maxBars)
+        guard count > 0 else { return [] }
+
+        return (0..<count).map { i in
+            ChartDataPoint(label: labels[i], value: values[i])
+        }
+    }
+}
+
+// MARK: - Preview
+
+#if DEBUG
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+#Preview("Bar Chart") {
+    let columns: [DataTable.Column] = [
+        .init(name: "department", index: 0, inferredType: .text),
+        .init(name: "revenue", index: 1, inferredType: .real),
+    ]
+    let departments = ["Engineering", "Sales", "Marketing", "Support", "Design"]
+    let rows: [DataTable.Row] = departments.enumerated().map { i, dept in
+        DataTable.Row(
+            id: i,
+            values: [.text(dept), .real(Double.random(in: 50_000...200_000))],
+            columnNames: ["department", "revenue"]
+        )
+    }
+    let table = DataTable(columns: columns, rows: rows)
+
+    BarChartView(
+        dataTable: table,
+        categoryColumn: "department",
+        valueColumn: "revenue",
+        title: "Revenue by Department"
+    )
+    .padding()
+    .frame(height: 300)
+}
+#endif

Sources/SwiftDBAI/Views/Charts/ChartDataPoint.swift

@@ -0,0 +1,21 @@
+// ChartDataPoint.swift
+// SwiftDBAI
+//
+// Shared data model used by all chart views.
+
+import Foundation
+
+/// A single data point for chart rendering.
+///
+/// Pairs a string label (category) with a numeric value.
+/// Used as the common data format across BarChartView,
+/// LineChartView, and PieChartView.
+struct ChartDataPoint: Sendable, Identifiable {
+    var id: String { label }
+
+    /// The category label (x-axis or slice label).
+    let label: String
+
+    /// The numeric value (y-axis or slice size).
+    let value: Double
+}

Sources/SwiftDBAI/Views/Charts/ChartResultView.swift

@@ -0,0 +1,135 @@
+// ChartResultView.swift
+// SwiftDBAI
+//
+// Auto-selecting chart view that uses ChartDataDetector to pick the
+// best chart type for a given DataTable.
+
+import SwiftUI
+import Charts
+
+/// A chart view that automatically selects the best chart type for a `DataTable`.
+///
+/// Uses `ChartDataDetector` to analyze the data shape and renders the
+/// appropriate chart (bar, line, or pie). If the data isn't suitable for
+/// charting, the view renders nothing.
+///
+/// Usage:
+/// ```swift
+/// ChartResultView(dataTable: myTable)
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct ChartResultView: View {
+
+    /// The data table to chart.
+    public let dataTable: DataTable
+
+    /// Optional override: force a specific chart type.
+    public var chartType: ChartDataDetector.ChartType?
+
+    /// The detector used to analyze the data.
+    private let detector: ChartDataDetector
+
+    public init(
+        dataTable: DataTable,
+        chartType: ChartDataDetector.ChartType? = nil,
+        detector: ChartDataDetector = ChartDataDetector()
+    ) {
+        self.dataTable = dataTable
+        self.chartType = chartType
+        self.detector = detector
+    }
+
+    public var body: some View {
+        if let recommendation = resolvedRecommendation {
+            VStack(alignment: .leading, spacing: 4) {
+                chartView(for: recommendation)
+
+                Text(recommendation.reason)
+                    .font(.caption2)
+                    .foregroundStyle(.tertiary)
+            }
+        }
+    }
+
+    // MARK: - Chart Selection
+
+    @ViewBuilder
+    private func chartView(
+        for recommendation: ChartDataDetector.ChartRecommendation
+    ) -> some View {
+        switch recommendation.chartType {
+        case .bar:
+            BarChartView(
+                dataTable: dataTable,
+                categoryColumn: recommendation.categoryColumn,
+                valueColumn: recommendation.valueColumn
+            )
+        case .line:
+            LineChartView(
+                dataTable: dataTable,
+                categoryColumn: recommendation.categoryColumn,
+                valueColumn: recommendation.valueColumn
+            )
+        case .pie:
+            PieChartView(
+                dataTable: dataTable,
+                categoryColumn: recommendation.categoryColumn,
+                valueColumn: recommendation.valueColumn
+            )
+        }
+    }
+
+    // MARK: - Resolution
+
+    /// Resolves the chart recommendation, using the override type if provided.
+    private var resolvedRecommendation: ChartDataDetector.ChartRecommendation? {
+        if let override = chartType {
+            // Use forced chart type — still need column pair from detector
+            let all = detector.allRecommendations(for: dataTable)
+            // Try to find recommendation for the forced type
+            if let match = all.first(where: { $0.chartType == override }) {
+                return match
+            }
+            // Fallback: use first recommendation and override its type
+            if let first = all.first {
+                return ChartDataDetector.ChartRecommendation(
+                    chartType: override,
+                    categoryColumn: first.categoryColumn,
+                    valueColumn: first.valueColumn,
+                    confidence: first.confidence * 0.8,
+                    reason: first.reason
+                )
+            }
+            return nil
+        }
+
+        // Auto-detect best chart type
+        return detector.detect(dataTable)
+    }
+}
+
+// MARK: - Preview
+
+#if DEBUG
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+#Preview("Auto Chart — Bar") {
+    let columns: [DataTable.Column] = [
+        .init(name: "city", index: 0, inferredType: .text),
+        .init(name: "population", index: 1, inferredType: .integer),
+    ]
+    let cities = ["NYC", "LA", "Chicago", "Houston", "Phoenix"]
+    let pops: [Int64] = [8_336_817, 3_979_576, 2_693_976, 2_320_268, 1_680_992]
+    let rows: [DataTable.Row] = cities.enumerated().map { i, city in
+        DataTable.Row(
+            id: i,
+            values: [.text(city), .integer(pops[i])],
+            columnNames: ["city", "population"]
+        )
+    }
+    let table = DataTable(columns: columns, rows: rows)
+
+    ChartResultView(dataTable: table)
+        .padding()
+        .frame(height: 300)
+}
+#endif

Sources/SwiftDBAI/Views/Charts/LineChartView.swift

@@ -0,0 +1,206 @@
+// LineChartView.swift
+// SwiftDBAI
+//
+// A SwiftUI line chart that renders DataTable values using Swift Charts.
+// Best for time series or sequential data (e.g., revenue over months).
+
+import SwiftUI
+import Charts
+
+/// A line chart view that renders a `DataTable` column pair using Swift Charts.
+///
+/// Displays a connected line with optional area fill, point markers,
+/// and smooth interpolation. Best suited for time series or sequential data.
+///
+/// Usage:
+/// ```swift
+/// LineChartView(
+///     dataTable: table,
+///     categoryColumn: "month",
+///     valueColumn: "revenue"
+/// )
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct LineChartView: View {
+
+    /// The data to chart.
+    public let dataTable: DataTable
+
+    /// Column name for category/time labels (x-axis).
+    public let categoryColumn: String
+
+    /// Column name for numeric values (y-axis).
+    public let valueColumn: String
+
+    /// Optional chart title.
+    public var title: String?
+
+    /// Whether to show an area fill below the line.
+    public var showAreaFill: Bool
+
+    /// Whether to show point markers at each data point.
+    public var showPoints: Bool
+
+    /// Maximum data points to display.
+    public var maxPoints: Int
+
+    public init(
+        dataTable: DataTable,
+        categoryColumn: String,
+        valueColumn: String,
+        title: String? = nil,
+        showAreaFill: Bool = true,
+        showPoints: Bool = true,
+        maxPoints: Int = 100
+    ) {
+        self.dataTable = dataTable
+        self.categoryColumn = categoryColumn
+        self.valueColumn = valueColumn
+        self.title = title
+        self.showAreaFill = showAreaFill
+        self.showPoints = showPoints
+        self.maxPoints = maxPoints
+    }
+
+    public var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            if let title {
+                Text(title)
+                    .font(.caption.weight(.semibold))
+                    .foregroundStyle(.secondary)
+            }
+
+            if chartData.isEmpty {
+                emptyChartView
+            } else {
+                chartContent
+            }
+        }
+    }
+
+    // MARK: - Chart Content
+
+    @ViewBuilder
+    private var chartContent: some View {
+        Chart(chartData, id: \.label) { item in
+            LineMark(
+                x: .value(categoryColumn, item.label),
+                y: .value(valueColumn, item.value)
+            )
+            .foregroundStyle(Color.accentColor)
+            .lineStyle(StrokeStyle(lineWidth: 2))
+            .interpolationMethod(.catmullRom)
+
+            if showAreaFill {
+                AreaMark(
+                    x: .value(categoryColumn, item.label),
+                    y: .value(valueColumn, item.value)
+                )
+                .foregroundStyle(
+                    .linearGradient(
+                        colors: [
+                            Color.accentColor.opacity(0.2),
+                            Color.accentColor.opacity(0.02),
+                        ],
+                        startPoint: .top,
+                        endPoint: .bottom
+                    )
+                )
+                .interpolationMethod(.catmullRom)
+            }
+
+            if showPoints {
+                PointMark(
+                    x: .value(categoryColumn, item.label),
+                    y: .value(valueColumn, item.value)
+                )
+                .foregroundStyle(Color.accentColor)
+                .symbolSize(30)
+            }
+        }
+        .chartXAxis {
+            AxisMarks(values: .automatic) { _ in
+                AxisValueLabel()
+                    .font(.caption2)
+            }
+        }
+        .chartYAxis {
+            AxisMarks(position: .leading) { _ in
+                AxisGridLine(stroke: StrokeStyle(lineWidth: 0.5, dash: [4, 4]))
+                    .foregroundStyle(.secondary.opacity(0.3))
+                AxisValueLabel()
+                    .font(.caption2)
+            }
+        }
+        .frame(minHeight: 200)
+
+        if isTruncated {
+            Text("Showing \(maxPoints) of \(dataTable.rowCount) data points")
+                .font(.caption2)
+                .foregroundStyle(.secondary)
+        }
+    }
+
+    // MARK: - Empty State
+
+    @ViewBuilder
+    private var emptyChartView: some View {
+        VStack(spacing: 8) {
+            Image(systemName: "chart.xyaxis.line")
+                .font(.title2)
+                .foregroundStyle(.secondary)
+            Text("No chartable data")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+        }
+        .frame(maxWidth: .infinity, minHeight: 100)
+    }
+
+    // MARK: - Data Extraction
+
+    private var isTruncated: Bool {
+        dataTable.rowCount > maxPoints
+    }
+
+    private var chartData: [ChartDataPoint] {
+        let labels = dataTable.stringValues(forColumn: categoryColumn)
+        let values = dataTable.numericValues(forColumn: valueColumn)
+
+        let count = min(labels.count, values.count, maxPoints)
+        guard count > 0 else { return [] }
+
+        return (0..<count).map { i in
+            ChartDataPoint(label: labels[i], value: values[i])
+        }
+    }
+}
+
+// MARK: - Preview
+
+#if DEBUG
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+#Preview("Line Chart") {
+    let columns: [DataTable.Column] = [
+        .init(name: "month", index: 0, inferredType: .text),
+        .init(name: "revenue", index: 1, inferredType: .real),
+    ]
+    let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun"]
+    let rows: [DataTable.Row] = months.enumerated().map { i, month in
+        DataTable.Row(
+            id: i,
+            values: [.text(month), .real(Double(i + 1) * 15_000 + Double.random(in: -3000...3000))],
+            columnNames: ["month", "revenue"]
+        )
+    }
+    let table = DataTable(columns: columns, rows: rows)
+
+    LineChartView(
+        dataTable: table,
+        categoryColumn: "month",
+        valueColumn: "revenue",
+        title: "Monthly Revenue"
+    )
+    .padding()
+    .frame(height: 300)
+}
+#endif

Sources/SwiftDBAI/Views/Charts/PieChartView.swift

@@ -0,0 +1,234 @@
+// PieChartView.swift
+// SwiftDBAI
+//
+// A SwiftUI pie/donut chart that renders DataTable values using Swift Charts.
+// Best for proportional breakdowns with few categories (e.g., market share).
+
+import SwiftUI
+import Charts
+
+/// A pie chart view that renders a `DataTable` column pair using Swift Charts.
+///
+/// Displays proportional slices with category labels. Each slice is
+/// automatically colored from a curated palette and sized relative to
+/// its proportion of the total. Best suited for data with few categories
+/// (≤ 8) where all values are positive.
+///
+/// Usage:
+/// ```swift
+/// PieChartView(
+///     dataTable: table,
+///     categoryColumn: "status",
+///     valueColumn: "count"
+/// )
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct PieChartView: View {
+
+    /// The data to chart.
+    public let dataTable: DataTable
+
+    /// Column name for category labels (slice labels).
+    public let categoryColumn: String
+
+    /// Column name for numeric values (slice sizes).
+    public let valueColumn: String
+
+    /// Optional chart title.
+    public var title: String?
+
+    /// Inner radius ratio for donut style (0 = full pie, >0 = donut).
+    public var innerRadiusRatio: CGFloat
+
+    /// Maximum number of slices before grouping remaining into "Other".
+    public var maxSlices: Int
+
+    public init(
+        dataTable: DataTable,
+        categoryColumn: String,
+        valueColumn: String,
+        title: String? = nil,
+        innerRadiusRatio: CGFloat = 0.4,
+        maxSlices: Int = 8
+    ) {
+        self.dataTable = dataTable
+        self.categoryColumn = categoryColumn
+        self.valueColumn = valueColumn
+        self.title = title
+        self.innerRadiusRatio = innerRadiusRatio
+        self.maxSlices = maxSlices
+    }
+
+    public var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            if let title {
+                Text(title)
+                    .font(.caption.weight(.semibold))
+                    .foregroundStyle(.secondary)
+            }
+
+            if chartData.isEmpty {
+                emptyChartView
+            } else {
+                HStack(alignment: .center, spacing: 16) {
+                    chartContent
+                    legendView
+                }
+            }
+        }
+    }
+
+    // MARK: - Chart Content
+
+    @ViewBuilder
+    private var chartContent: some View {
+        Chart(chartData, id: \.label) { item in
+            SectorMark(
+                angle: .value(valueColumn, item.value),
+                innerRadius: .ratio(innerRadiusRatio),
+                angularInset: 1.5
+            )
+            .foregroundStyle(by: .value(categoryColumn, item.label))
+            .cornerRadius(3)
+        }
+        .chartForegroundStyleScale(
+            domain: chartData.map(\.label),
+            range: sliceColors
+        )
+        .chartLegend(.hidden)
+        .frame(minWidth: 150, minHeight: 150)
+        .aspectRatio(1, contentMode: .fit)
+    }
+
+    // MARK: - Legend
+
+    @ViewBuilder
+    private var legendView: some View {
+        VStack(alignment: .leading, spacing: 6) {
+            ForEach(Array(chartData.enumerated()), id: \.element.label) { index, item in
+                HStack(spacing: 8) {
+                    Circle()
+                        .fill(sliceColors[index % sliceColors.count])
+                        .frame(width: 8, height: 8)
+
+                    Text(item.label)
+                        .font(.caption)
+                        .foregroundStyle(.primary)
+                        .lineLimit(1)
+
+                    Spacer()
+
+                    Text(percentageText(for: item.value))
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                        .monospacedDigit()
+                }
+            }
+        }
+    }
+
+    // MARK: - Empty State
+
+    @ViewBuilder
+    private var emptyChartView: some View {
+        VStack(spacing: 8) {
+            Image(systemName: "chart.pie")
+                .font(.title2)
+                .foregroundStyle(.secondary)
+            Text("No chartable data")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+        }
+        .frame(maxWidth: .infinity, minHeight: 100)
+    }
+
+    // MARK: - Colors
+
+    /// Curated color palette for pie slices.
+    private var sliceColors: [Color] {
+        [
+            .blue,
+            .green,
+            .orange,
+            .purple,
+            .pink,
+            .cyan,
+            .yellow,
+            .indigo,
+            .mint,
+            .teal,
+        ]
+    }
+
+    // MARK: - Helpers
+
+    private var total: Double {
+        chartData.reduce(0) { $0 + $1.value }
+    }
+
+    private func percentageText(for value: Double) -> String {
+        guard total > 0 else { return "0%" }
+        let pct = (value / total) * 100
+        if pct >= 10 {
+            return String(format: "%.0f%%", pct)
+        }
+        return String(format: "%.1f%%", pct)
+    }
+
+    // MARK: - Data Extraction
+
+    private var chartData: [ChartDataPoint] {
+        let labels = dataTable.stringValues(forColumn: categoryColumn)
+        let values = dataTable.numericValues(forColumn: valueColumn)
+
+        let count = min(labels.count, values.count)
+        guard count > 0 else { return [] }
+
+        // Build all points, sorted by value descending
+        var points = (0..<count).map { i in
+            ChartDataPoint(label: labels[i], value: values[i])
+        }
+        .filter { $0.value > 0 }
+        .sorted { $0.value > $1.value }
+
+        // Group excess slices into "Other"
+        if points.count > maxSlices {
+            let kept = Array(points.prefix(maxSlices - 1))
+            let otherValue = points.dropFirst(maxSlices - 1).reduce(0) { $0 + $1.value }
+            points = kept + [ChartDataPoint(label: "Other", value: otherValue)]
+        }
+
+        return points
+    }
+}
+
+// MARK: - Preview
+
+#if DEBUG
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+#Preview("Pie Chart") {
+    let columns: [DataTable.Column] = [
+        .init(name: "status", index: 0, inferredType: .text),
+        .init(name: "count", index: 1, inferredType: .integer),
+    ]
+    let statuses = ["Active", "Inactive", "Pending", "Archived"]
+    let counts: [Int64] = [45, 20, 15, 10]
+    let rows: [DataTable.Row] = statuses.enumerated().map { i, status in
+        DataTable.Row(
+            id: i,
+            values: [.text(status), .integer(counts[i])],
+            columnNames: ["status", "count"]
+        )
+    }
+    let table = DataTable(columns: columns, rows: rows)
+
+    PieChartView(
+        dataTable: table,
+        categoryColumn: "status",
+        valueColumn: "count",
+        title: "Users by Status"
+    )
+    .padding()
+    .frame(height: 250)
+}
+#endif

Sources/SwiftDBAI/Views/ChatView.swift

@@ -0,0 +1,214 @@
+// ChatView.swift
+// SwiftDBAI
+//
+// Drop-in SwiftUI view for chatting with a SQLite database.
+// Renders messages with automatic data table display for query results.
+
+import SwiftUI
+
+/// A drop-in SwiftUI chat interface for querying SQLite databases
+/// with natural language.
+///
+/// `ChatView` renders the full conversation including:
+/// - User messages (right-aligned, accent-colored)
+/// - Assistant responses with text summaries
+/// - **Automatic data tables** via `ScrollableDataTableView` when query results
+///   contain tabular data (rows + columns)
+/// - SQL query disclosure for transparency
+/// - Error messages with red styling
+/// - A loading indicator while the engine is processing
+///
+/// Usage:
+/// ```swift
+/// let engine = ChatEngine(database: myPool, model: myModel)
+/// let viewModel = ChatViewModel(engine: engine)
+///
+/// ChatView(viewModel: viewModel)
+/// ```
+///
+/// Or use the convenience initializer:
+/// ```swift
+/// ChatView(engine: myEngine)
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct ChatView: View {
+    @Bindable private var viewModel: ChatViewModel
+    @State private var inputText: String = ""
+    @FocusState private var isInputFocused: Bool
+
+    /// Creates a ChatView with an existing view model.
+    ///
+    /// - Parameter viewModel: The `ChatViewModel` driving this view.
+    public init(viewModel: ChatViewModel) {
+        self.viewModel = viewModel
+    }
+
+    /// Creates a ChatView with a `ChatEngine`, automatically creating
+    /// a `ChatViewModel`.
+    ///
+    /// - Parameter engine: The `ChatEngine` to power the chat.
+    public init(engine: ChatEngine) {
+        self.viewModel = ChatViewModel(engine: engine)
+    }
+
+    public var body: some View {
+        VStack(spacing: 0) {
+            messageList
+            Divider()
+            inputBar
+        }
+    }
+
+    // MARK: - Message List
+
+    @ViewBuilder
+    private var messageList: some View {
+        ScrollViewReader { proxy in
+            ScrollView {
+                LazyVStack(spacing: 12) {
+                    if viewModel.messages.isEmpty {
+                        emptyState
+                    }
+
+                    ForEach(viewModel.messages) { message in
+                        messageBubble(for: message)
+                            .id(message.id)
+                    }
+
+                    if viewModel.isLoading {
+                        loadingIndicator
+                    }
+                }
+                .padding(.horizontal, 16)
+                .padding(.vertical, 12)
+            }
+            .onChange(of: viewModel.messages.count) { _, _ in
+                if let lastMessage = viewModel.messages.last {
+                    withAnimation(.easeOut(duration: 0.3)) {
+                        proxy.scrollTo(lastMessage.id, anchor: .bottom)
+                    }
+                }
+            }
+        }
+    }
+
+    // MARK: - Empty State
+
+    @ViewBuilder
+    private var emptyState: some View {
+        VStack(spacing: 12) {
+            Image(systemName: "bubble.left.and.text.bubble.right")
+                .font(.system(size: 40))
+                .foregroundStyle(.tertiary)
+            Text("Ask a question about your data")
+                .font(.headline)
+                .foregroundStyle(.secondary)
+            Text("Try something like \"How many records are in the database?\"")
+                .font(.subheadline)
+                .foregroundStyle(.tertiary)
+                .multilineTextAlignment(.center)
+        }
+        .frame(maxWidth: .infinity)
+        .padding(.vertical, 60)
+    }
+
+    // MARK: - Loading Indicator
+
+    @ViewBuilder
+    private var loadingIndicator: some View {
+        HStack(alignment: .top) {
+            HStack(spacing: 8) {
+                ProgressView()
+                    .controlSize(.small)
+                Text("Querying…")
+                    .font(.callout)
+                    .foregroundStyle(.secondary)
+            }
+            .padding(.horizontal, 14)
+            .padding(.vertical, 10)
+            .background(
+                Self.assistantBackgroundColor,
+                in: RoundedRectangle(cornerRadius: 16, style: .continuous)
+            )
+
+            Spacer(minLength: 48)
+        }
+        .id("loading-indicator")
+        .transition(.opacity.combined(with: .move(edge: .bottom)))
+    }
+
+    private static var assistantBackgroundColor: Color {
+        #if os(macOS)
+        Color(nsColor: .controlBackgroundColor)
+        #else
+        Color(uiColor: .secondarySystemGroupedBackground)
+        #endif
+    }
+
+    // MARK: - Input Bar
+
+    @ViewBuilder
+    private var inputBar: some View {
+        HStack(spacing: 8) {
+            TextField("Ask about your data…", text: $inputText, axis: .vertical)
+                .textFieldStyle(.plain)
+                .lineLimit(1...5)
+                .focused($isInputFocused)
+                .onSubmit { sendMessage() }
+                .submitLabel(.send)
+
+            Button(action: sendMessage) {
+                Image(systemName: "arrow.up.circle.fill")
+                    .font(.title2)
+                    .foregroundStyle(canSend ? Color.accentColor : Color.secondary)
+            }
+            .disabled(!canSend)
+            .keyboardShortcut(.return, modifiers: .command)
+        }
+        .padding(.horizontal, 16)
+        .padding(.vertical, 10)
+    }
+
+    // MARK: - Message Bubble
+
+    @ViewBuilder
+    private func messageBubble(for message: ChatMessage) -> some View {
+        if message.role == .error {
+            MessageBubbleView(
+                message: message,
+                onRetry: makeRetryAction(for: message)
+            )
+        } else {
+            MessageBubbleView(message: message)
+        }
+    }
+
+    private func makeRetryAction(for errorMessage: ChatMessage) -> @Sendable () async -> Void {
+        let vm = viewModel
+        let messageId = errorMessage.id
+        return { @MainActor [vm] in
+            let allMessages = await MainActor.run { vm.messages }
+            if let lastUserMessage = allMessages
+                .prefix(while: { $0.id != messageId })
+                .last(where: { $0.role == .user }) {
+                await vm.send(lastUserMessage.content)
+            }
+        }
+    }
+
+    // MARK: - Helpers
+
+    private var canSend: Bool {
+        !inputText.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && !viewModel.isLoading
+    }
+
+    private func sendMessage() {
+        guard canSend else { return }
+        let text = inputText
+        inputText = ""
+
+        Task {
+            await viewModel.send(text)
+        }
+    }
+}

Sources/SwiftDBAI/Views/ChatViewModel.swift

@@ -0,0 +1,137 @@
+// ChatViewModel.swift
+// SwiftDBAI
+//
+// Observable view model that bridges ChatEngine with the SwiftUI ChatView.
+
+import Foundation
+import Observation
+
+/// The readiness state of the schema introspection.
+public enum SchemaReadiness: Sendable, Equatable {
+    /// Schema has not been loaded yet.
+    case idle
+    /// Schema introspection is in progress.
+    case loading
+    /// Schema is ready with the given number of tables.
+    case ready(tableCount: Int)
+    /// Schema introspection failed.
+    case failed(String)
+
+    public var isReady: Bool {
+        if case .ready = self { return true }
+        return false
+    }
+}
+
+/// Observable view model that drives the `ChatView`.
+///
+/// Wraps `ChatEngine` to provide reactive state updates for the SwiftUI layer.
+/// Manages the message list, loading state, error presentation, and schema
+/// readiness. Call ``prepare()`` at view-appear time to eagerly introspect the
+/// database schema.
+///
+/// Usage:
+/// ```swift
+/// let viewModel = ChatViewModel(engine: myChatEngine)
+/// ChatView(viewModel: viewModel)
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+@Observable
+@MainActor
+public final class ChatViewModel {
+
+    // MARK: - Public State
+
+    /// All messages in the conversation, in chronological order.
+    public private(set) var messages: [ChatMessage] = []
+
+    /// Whether the engine is currently processing a request.
+    public private(set) var isLoading: Bool = false
+
+    /// The most recent error message, if any. Cleared on next send.
+    public private(set) var errorMessage: String?
+
+    /// Current schema readiness state.
+    public private(set) var schemaReadiness: SchemaReadiness = .idle
+
+    // MARK: - Dependencies
+
+    private let engine: ChatEngine
+
+    // MARK: - Initialization
+
+    /// Creates a new ChatViewModel.
+    ///
+    /// - Parameter engine: The `ChatEngine` to use for processing messages.
+    public init(engine: ChatEngine) {
+        self.engine = engine
+    }
+
+    // MARK: - Schema Preparation
+
+    /// Eagerly introspects the database schema so it's ready before the first query.
+    ///
+    /// This should be called from a `.task` modifier on the view. It transitions
+    /// `schemaReadiness` through `.loading` → `.ready` (or `.failed`).
+    /// If the schema is already cached, this completes immediately.
+    public func prepare() async {
+        // Don't re-prepare if already ready
+        if schemaReadiness.isReady { return }
+
+        schemaReadiness = .loading
+
+        do {
+            let schema = try await engine.prepareSchema()
+            schemaReadiness = .ready(tableCount: schema.tableNames.count)
+        } catch {
+            schemaReadiness = .failed(error.localizedDescription)
+        }
+    }
+
+    // MARK: - Public API
+
+    /// Sends a user message and appends the response to the conversation.
+    ///
+    /// - Parameter text: The natural language message from the user.
+    public func send(_ text: String) async {
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty else { return }
+
+        errorMessage = nil
+
+        // Add user message immediately
+        let userMessage = ChatMessage(role: .user, content: trimmed)
+        messages.append(userMessage)
+
+        isLoading = true
+        defer { isLoading = false }
+
+        do {
+            let response = try await engine.send(trimmed)
+
+            let assistantMessage = ChatMessage(
+                role: .assistant,
+                content: response.summary,
+                queryResult: response.queryResult,
+                sql: response.sql
+            )
+            messages.append(assistantMessage)
+        } catch {
+            let typedError = (error as? SwiftDBAIError)
+            let errorMsg = ChatMessage(
+                role: .error,
+                content: error.localizedDescription,
+                error: typedError
+            )
+            messages.append(errorMsg)
+            errorMessage = error.localizedDescription
+        }
+    }
+
+    /// Clears the conversation and resets the engine state.
+    public func reset() {
+        messages.removeAll()
+        errorMessage = nil
+        engine.reset()
+    }
+}

Sources/SwiftDBAI/Views/DataChatView.swift

@@ -0,0 +1,220 @@
+// DataChatView.swift
+// SwiftDBAI
+//
+// Zero-config SwiftUI view: provide a database path and a model, get a chat UI.
+
+import AnyLanguageModel
+import GRDB
+import SwiftUI
+
+/// A convenience SwiftUI view that wraps the full chat-with-database stack.
+///
+/// `DataChatView` is the simplest entry point into SwiftDBAI. It requires only
+/// a database file path and a language model — no schema files, no annotations,
+/// no manual setup. The view creates a GRDB connection, a `ChatEngine`,
+/// a `ChatViewModel`, and renders a fully functional `ChatView`.
+///
+/// Usage with just a path and model:
+/// ```swift
+/// DataChatView(
+///     databasePath: "/path/to/mydata.sqlite",
+///     model: OllamaLanguageModel(model: "llama3")
+/// )
+/// ```
+///
+/// Usage with additional configuration:
+/// ```swift
+/// DataChatView(
+///     databasePath: documentsURL.appendingPathComponent("app.db").path,
+///     model: OpenAILanguageModel(apiKey: key),
+///     allowlist: .standard,
+///     additionalContext: "This database stores a recipe app's data."
+/// )
+/// ```
+///
+/// If you already have a GRDB `DatabasePool` or `DatabaseQueue`, use
+/// `ChatView` with a `ChatEngine` directly for full control.
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct DataChatView: View {
+    @State private var viewModel: ChatViewModel
+    @State private var loadError: DataChatError?
+
+    /// Creates a DataChatView from a database file path and language model.
+    ///
+    /// This is the zero-config convenience initializer. It opens a GRDB
+    /// `DatabasePool` at the given path, creates a `ChatEngine` with
+    /// read-only defaults, and wires up the full chat UI.
+    ///
+    /// - Parameters:
+    ///   - databasePath: Absolute path to a SQLite database file.
+    ///   - model: Any `AnyLanguageModel`-compatible language model instance.
+    ///   - allowlist: SQL operations the LLM may generate. Defaults to `.readOnly` (SELECT only).
+    ///   - additionalContext: Optional extra context about the database for the LLM system prompt
+    ///     (e.g., "This database stores e-commerce orders and products.").
+    ///   - maxSummaryRows: Maximum rows to include when summarizing results (default: 50).
+    public init(
+        databasePath: String,
+        model: any LanguageModel,
+        allowlist: OperationAllowlist = .readOnly,
+        additionalContext: String? = nil,
+        maxSummaryRows: Int = 50
+    ) {
+        do {
+            let pool = try DatabasePool(path: databasePath)
+            let engine = ChatEngine(
+                database: pool,
+                model: model,
+                allowlist: allowlist,
+                additionalContext: additionalContext,
+                maxSummaryRows: maxSummaryRows
+            )
+            self._viewModel = State(initialValue: ChatViewModel(engine: engine))
+            self._loadError = State(initialValue: nil)
+        } catch {
+            // If the database can't be opened, create a placeholder engine
+            // and store the error to display in the UI.
+            let queue = try! DatabaseQueue()
+            let engine = ChatEngine(
+                database: queue,
+                model: model,
+                allowlist: allowlist,
+                additionalContext: additionalContext,
+                maxSummaryRows: maxSummaryRows
+            )
+            self._viewModel = State(initialValue: ChatViewModel(engine: engine))
+            self._loadError = State(initialValue: DataChatError.databaseOpenFailed(
+                path: databasePath,
+                underlying: error
+            ))
+        }
+    }
+
+    /// Creates a DataChatView from an existing GRDB database connection and language model.
+    ///
+    /// Use this initializer when you already have a configured `DatabasePool` or
+    /// `DatabaseQueue` and want the convenience of `DataChatView` without
+    /// creating a `ChatEngine` yourself.
+    ///
+    /// - Parameters:
+    ///   - database: A GRDB `DatabaseWriter` (`DatabasePool` or `DatabaseQueue`).
+    ///   - model: Any `AnyLanguageModel`-compatible language model instance.
+    ///   - allowlist: SQL operations the LLM may generate. Defaults to `.readOnly`.
+    ///   - additionalContext: Optional extra context about the database for the LLM.
+    ///   - maxSummaryRows: Maximum rows to include when summarizing results (default: 50).
+    public init(
+        database: any DatabaseWriter,
+        model: any LanguageModel,
+        allowlist: OperationAllowlist = .readOnly,
+        additionalContext: String? = nil,
+        maxSummaryRows: Int = 50
+    ) {
+        let engine = ChatEngine(
+            database: database,
+            model: model,
+            allowlist: allowlist,
+            additionalContext: additionalContext,
+            maxSummaryRows: maxSummaryRows
+        )
+        self._viewModel = State(initialValue: ChatViewModel(engine: engine))
+        self._loadError = State(initialValue: nil)
+    }
+
+    public var body: some View {
+        if let error = loadError {
+            errorView(error)
+        } else {
+            ChatView(viewModel: viewModel)
+                .task {
+                    await viewModel.prepare()
+                }
+                .overlay {
+                    if case .loading = viewModel.schemaReadiness {
+                        schemaLoadingView
+                    }
+                    if case .failed(let reason) = viewModel.schemaReadiness {
+                        schemaErrorView(reason)
+                    }
+                }
+        }
+    }
+
+    // MARK: - Schema Loading View
+
+    @ViewBuilder
+    private var schemaLoadingView: some View {
+        VStack(spacing: 16) {
+            ProgressView()
+                .controlSize(.large)
+            Text("Introspecting database schema…")
+                .font(.subheadline)
+                .foregroundStyle(.secondary)
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .background(.ultraThinMaterial)
+    }
+
+    // MARK: - Schema Error View
+
+    @ViewBuilder
+    private func schemaErrorView(_ reason: String) -> some View {
+        VStack(spacing: 16) {
+            Image(systemName: "exclamationmark.triangle.fill")
+                .font(.system(size: 40))
+                .foregroundStyle(.orange)
+
+            Text("Schema Introspection Failed")
+                .font(.headline)
+
+            Text(reason)
+                .font(.subheadline)
+                .foregroundStyle(.secondary)
+                .multilineTextAlignment(.center)
+                .padding(.horizontal, 32)
+
+            Button("Retry") {
+                Task {
+                    await viewModel.prepare()
+                }
+            }
+            .buttonStyle(.borderedProminent)
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .background(.ultraThinMaterial)
+    }
+
+    // MARK: - Database Open Error View
+
+    @ViewBuilder
+    private func errorView(_ error: DataChatError) -> some View {
+        VStack(spacing: 16) {
+            Image(systemName: "exclamationmark.triangle.fill")
+                .font(.system(size: 40))
+                .foregroundStyle(.red)
+
+            Text("Unable to Open Database")
+                .font(.headline)
+
+            Text(error.localizedDescription)
+                .font(.subheadline)
+                .foregroundStyle(.secondary)
+                .multilineTextAlignment(.center)
+                .padding(.horizontal, 32)
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+    }
+}
+
+// MARK: - Errors
+
+/// Errors specific to `DataChatView` initialization.
+public enum DataChatError: Error, LocalizedError, Sendable {
+    /// The database file could not be opened at the given path.
+    case databaseOpenFailed(path: String, underlying: any Error)
+
+    public var errorDescription: String? {
+        switch self {
+        case .databaseOpenFailed(let path, let underlying):
+            return "Could not open database at \"\(path)\": \(underlying.localizedDescription)"
+        }
+    }
+}

Sources/SwiftDBAI/Views/ErrorMessageView.swift

@@ -0,0 +1,360 @@
+// ErrorMessageView.swift
+// SwiftDBAI
+//
+// Reusable SwiftUI component that renders error messages with contextual
+// icons, descriptions, and optional retry actions based on the error type.
+
+import SwiftUI
+
+/// A reusable SwiftUI component that renders a ``SwiftDBAIError`` with an
+/// appropriate icon, human-readable message, and optional retry action.
+///
+/// The view automatically selects a visual treatment based on the error
+/// category:
+///
+/// | Category          | Icon                          | Color   | Retry? |
+/// |-------------------|-------------------------------|---------|--------|
+/// | Safety / blocked  | `shield.trianglebadge.excl…`  | Orange  | No     |
+/// | Confirmation      | `hand.raised.fill`            | Yellow  | Yes*   |
+/// | LLM failure       | `brain`                       | Purple  | Yes    |
+/// | Schema / DB       | `cylinder.split.1x2`          | Red     | No     |
+/// | Recoverable SQL   | `arrow.clockwise`             | Blue    | Yes    |
+/// | Generic           | `exclamationmark.triangle`    | Red     | No     |
+///
+/// *Confirmation retry triggers the confirm callback, not a standard retry.
+///
+/// Usage:
+/// ```swift
+/// ErrorMessageView(
+///     error: .llmTimeout(seconds: 30),
+///     onRetry: { /* resend the message */ }
+/// )
+/// ```
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+public struct ErrorMessageView: View {
+    /// The error to display. When `nil`, the view falls back to the raw message.
+    private let error: SwiftDBAIError?
+
+    /// The raw error message string (used as fallback when error is nil).
+    private let message: String
+
+    /// Called when the user taps the retry button. `nil` hides the button.
+    private let onRetry: (@Sendable () async -> Void)?
+
+    /// Called when the user confirms a destructive operation.
+    private let onConfirm: (@Sendable () async -> Void)?
+
+    @State private var isRetrying = false
+
+    // MARK: - Initializers
+
+    /// Creates an ErrorMessageView from a typed ``SwiftDBAIError``.
+    ///
+    /// - Parameters:
+    ///   - error: The ``SwiftDBAIError`` to display.
+    ///   - onRetry: An optional async closure invoked when the user taps retry.
+    ///   - onConfirm: An optional async closure invoked when the user confirms
+    ///     a destructive operation (only relevant for `.confirmationRequired`).
+    public init(
+        error: SwiftDBAIError,
+        onRetry: (@Sendable () async -> Void)? = nil,
+        onConfirm: (@Sendable () async -> Void)? = nil
+    ) {
+        self.error = error
+        self.message = error.localizedDescription
+        self.onRetry = onRetry
+        self.onConfirm = onConfirm
+    }
+
+    /// Creates an ErrorMessageView from a ``ChatMessage``.
+    ///
+    /// Extracts the typed error if available, otherwise falls back to the
+    /// message content string.
+    ///
+    /// - Parameters:
+    ///   - message: The chat message with role `.error`.
+    ///   - onRetry: An optional async closure invoked when the user taps retry.
+    ///   - onConfirm: An optional async closure invoked when the user confirms
+    ///     a destructive operation.
+    public init(
+        chatMessage: ChatMessage,
+        onRetry: (@Sendable () async -> Void)? = nil,
+        onConfirm: (@Sendable () async -> Void)? = nil
+    ) {
+        self.error = chatMessage.error
+        self.message = chatMessage.content
+        self.onRetry = onRetry
+        self.onConfirm = onConfirm
+    }
+
+    /// Creates an ErrorMessageView from a plain string (untyped fallback).
+    ///
+    /// - Parameters:
+    ///   - message: The error message string.
+    ///   - onRetry: An optional async closure invoked when the user taps retry.
+    public init(
+        message: String,
+        onRetry: (@Sendable () async -> Void)? = nil
+    ) {
+        self.error = nil
+        self.message = message
+        self.onRetry = onRetry
+        self.onConfirm = nil
+    }
+
+    // MARK: - Body
+
+    public var body: some View {
+        VStack(alignment: .leading, spacing: 10) {
+            // Icon + message row
+            HStack(alignment: .firstTextBaseline, spacing: 8) {
+                Image(systemName: iconName)
+                    .foregroundStyle(iconColor)
+                    .font(.callout)
+                    .accessibilityHidden(true)
+
+                VStack(alignment: .leading, spacing: 4) {
+                    if let title = errorTitle {
+                        Text(title)
+                            .font(.callout.weight(.semibold))
+                            .foregroundStyle(iconColor)
+                    }
+
+                    Text(message)
+                        .font(.body)
+                        .foregroundStyle(.primary)
+                        .textSelection(.enabled)
+                        .fixedSize(horizontal: false, vertical: true)
+
+                    if let hint = recoveryHint {
+                        Text(hint)
+                            .font(.caption)
+                            .foregroundStyle(.secondary)
+                            .fixedSize(horizontal: false, vertical: true)
+                    }
+                }
+            }
+
+            // Action buttons
+            if showRetryButton || showConfirmButton {
+                HStack(spacing: 12) {
+                    if showConfirmButton {
+                        confirmButton
+                    }
+                    if showRetryButton {
+                        retryButton
+                    }
+                }
+                .padding(.leading, 26) // Align with text (icon width + spacing)
+            }
+        }
+        .accessibilityElement(children: .combine)
+        .accessibilityLabel(accessibilityDescription)
+    }
+
+    // MARK: - Action Buttons
+
+    @ViewBuilder
+    private var retryButton: some View {
+        Button {
+            guard !isRetrying else { return }
+            isRetrying = true
+            Task {
+                await onRetry?()
+                isRetrying = false
+            }
+        } label: {
+            HStack(spacing: 4) {
+                if isRetrying {
+                    ProgressView()
+                        .controlSize(.mini)
+                } else {
+                    Image(systemName: "arrow.clockwise")
+                        .font(.caption)
+                }
+                Text(retryButtonLabel)
+                    .font(.caption.weight(.medium))
+            }
+            .padding(.horizontal, 10)
+            .padding(.vertical, 6)
+            .background(iconColor.opacity(0.12))
+            .foregroundStyle(iconColor)
+            .clipShape(Capsule())
+        }
+        .buttonStyle(.plain)
+        .disabled(isRetrying)
+    }
+
+    @ViewBuilder
+    private var confirmButton: some View {
+        Button {
+            Task {
+                await onConfirm?()
+            }
+        } label: {
+            HStack(spacing: 4) {
+                Image(systemName: "checkmark.circle")
+                    .font(.caption)
+                Text("Confirm")
+                    .font(.caption.weight(.medium))
+            }
+            .padding(.horizontal, 10)
+            .padding(.vertical, 6)
+            .background(Color.orange.opacity(0.12))
+            .foregroundStyle(.orange)
+            .clipShape(Capsule())
+        }
+        .buttonStyle(.plain)
+    }
+
+    // MARK: - Error Classification
+
+    private var errorCategory: ErrorCategory {
+        guard let error else { return .generic }
+
+        if error.requiresUserAction {
+            return .confirmation
+        }
+        if error.isSafetyError {
+            return .safety
+        }
+        if error.isRecoverable {
+            return .recoverable
+        }
+
+        switch error {
+        case .llmFailure, .llmResponseUnparseable, .llmTimeout:
+            return .llm
+        case .schemaIntrospectionFailed, .emptySchema, .databaseError, .queryTimedOut:
+            return .database
+        case .configurationError:
+            return .configuration
+        default:
+            return .generic
+        }
+    }
+
+    private enum ErrorCategory {
+        case safety
+        case confirmation
+        case llm
+        case database
+        case recoverable
+        case configuration
+        case generic
+    }
+
+    // MARK: - Visual Properties
+
+    private var iconName: String {
+        switch errorCategory {
+        case .safety:
+            return "shield.trianglebadge.exclamationmark.fill"
+        case .confirmation:
+            return "hand.raised.fill"
+        case .llm:
+            return "brain"
+        case .database:
+            return "cylinder.split.1x2"
+        case .recoverable:
+            return "arrow.clockwise"
+        case .configuration:
+            return "gearshape.triangle.fill"
+        case .generic:
+            return "exclamationmark.triangle.fill"
+        }
+    }
+
+    private var iconColor: Color {
+        switch errorCategory {
+        case .safety:
+            return .orange
+        case .confirmation:
+            return .yellow
+        case .llm:
+            return .purple
+        case .database:
+            return .red
+        case .recoverable:
+            return .blue
+        case .configuration:
+            return .gray
+        case .generic:
+            return .red
+        }
+    }
+
+    private var errorTitle: String? {
+        switch errorCategory {
+        case .safety:
+            return "Operation Blocked"
+        case .confirmation:
+            return "Confirmation Required"
+        case .llm:
+            return "AI Provider Error"
+        case .database:
+            return "Database Error"
+        case .recoverable:
+            return "Query Issue"
+        case .configuration:
+            return "Configuration Error"
+        case .generic:
+            return nil
+        }
+    }
+
+    private var recoveryHint: String? {
+        guard let error else { return nil }
+
+        switch error {
+        case .noSQLGenerated, .llmResponseUnparseable:
+            return "Try rephrasing your question."
+        case .tableNotFound:
+            return "Check that you're referring to an existing table."
+        case .columnNotFound:
+            return "Verify the column name matches your schema."
+        case .invalidSQL:
+            return "The AI generated an invalid query. Try asking differently."
+        case .llmTimeout:
+            return "The AI took too long. Try a simpler question."
+        case .llmFailure:
+            return "The AI service may be temporarily unavailable."
+        case .emptySchema:
+            return "Add some tables to your database first."
+        case .queryTimedOut:
+            return "Try a simpler query or add database indexes."
+        default:
+            return nil
+        }
+    }
+
+    // MARK: - Button Visibility
+
+    private var showRetryButton: Bool {
+        guard onRetry != nil else { return false }
+        return errorCategory == .recoverable || errorCategory == .llm
+    }
+
+    private var showConfirmButton: Bool {
+        guard onConfirm != nil else { return false }
+        return errorCategory == .confirmation
+    }
+
+    private var retryButtonLabel: String {
+        switch errorCategory {
+        case .llm:
+            return "Retry"
+        case .recoverable:
+            return "Try Again"
+        default:
+            return "Retry"
+        }
+    }
+
+    // MARK: - Accessibility
+
+    private var accessibilityDescription: String {
+        let prefix = errorTitle.map { "\($0): " } ?? "Error: "
+        return prefix + message
+    }
+}

Sources/SwiftDBAI/Views/MessageBubbleView.swift

@@ -0,0 +1,205 @@
+// MessageBubbleView.swift
+// SwiftDBAI
+//
+// Renders a single ChatMessage as a styled bubble with optional
+// data table and SQL disclosure for query results.
+
+import SwiftUI
+import Charts
+
+/// Renders a single `ChatMessage` in the chat conversation.
+///
+/// - **User messages** display right-aligned with an accent-colored background
+///   and white text, using a continuous rounded rectangle shape.
+/// - **Assistant messages** display left-aligned with a secondary background.
+///   The natural language text summary is the primary content, rendered with
+///   full `.body` font and `.primary` foreground for readability.
+///   If the message contains a `queryResult` with tabular data, a
+///   `ScrollableDataTableView` is automatically embedded below the summary.
+///   An optional SQL disclosure group shows the generated query.
+/// - **Error messages** display left-aligned with a red-tinted background
+///   and an exclamation mark icon.
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+struct MessageBubbleView: View {
+    let message: ChatMessage
+
+    /// Whether to show the SQL query in a disclosure group.
+    var showSQL: Bool = true
+
+    /// Maximum height for the data table before it scrolls.
+    var maxTableHeight: CGFloat = 300
+
+    /// Called when the user taps "Retry" on a recoverable error.
+    var onRetry: (@Sendable () async -> Void)?
+
+    /// Called when the user confirms a destructive operation.
+    var onConfirm: (@Sendable () async -> Void)?
+
+    var body: some View {
+        HStack(alignment: .top) {
+            if message.role == .user { Spacer(minLength: 48) }
+
+            bubbleContent
+                .padding(.horizontal, 14)
+                .padding(.vertical, 10)
+                .background(bubbleBackground)
+                .clipShape(bubbleShape)
+
+            if message.role != .user { Spacer(minLength: 48) }
+        }
+    }
+
+    // MARK: - Bubble Content
+
+    @ViewBuilder
+    private var bubbleContent: some View {
+        switch message.role {
+        case .user:
+            userContent
+        case .assistant:
+            assistantContent
+        case .error:
+            errorContent
+        }
+    }
+
+    // MARK: - User Content
+
+    @ViewBuilder
+    private var userContent: some View {
+        Text(message.content)
+            .font(.body)
+            .foregroundStyle(.white)
+            .textSelection(.enabled)
+    }
+
+    // MARK: - Assistant Content (Text Summary + Data Table + SQL)
+
+    @ViewBuilder
+    private var assistantContent: some View {
+        VStack(alignment: .leading, spacing: 10) {
+            // Natural language text summary — primary content
+            Text(message.content)
+                .font(.body)
+                .foregroundStyle(.primary)
+                .textSelection(.enabled)
+                .fixedSize(horizontal: false, vertical: true)
+
+            // Data table — automatically shown when queryResult has tabular data
+            if let queryResult = message.queryResult,
+               !queryResult.columns.isEmpty,
+               !queryResult.rows.isEmpty {
+                dataTableSection(for: queryResult)
+            }
+
+            // SQL disclosure — collapsed by default for transparency
+            if showSQL, let sql = message.sql {
+                sqlDisclosure(sql: sql)
+            }
+        }
+    }
+
+    // MARK: - Error Content
+
+    @ViewBuilder
+    private var errorContent: some View {
+        ErrorMessageView(
+            chatMessage: message,
+            onRetry: onRetry,
+            onConfirm: onConfirm
+        )
+    }
+
+    /// Maximum height for the chart section.
+    var maxChartHeight: CGFloat = 250
+
+    /// Whether to show auto-detected charts. Defaults to `true`.
+    var showCharts: Bool = true
+
+    // MARK: - Chart Detection
+
+    /// The shared detector used for chart eligibility checks.
+    private static let chartDetector = ChartDataDetector()
+
+    // MARK: - Data Table Section
+
+    @ViewBuilder
+    private func dataTableSection(for queryResult: QueryResult) -> some View {
+        let dataTable = DataTable(queryResult)
+
+        VStack(alignment: .leading, spacing: 8) {
+            // Chart — automatically shown when ChartDataDetector finds eligible data
+            if showCharts {
+                chartSection(for: dataTable)
+            }
+
+            Divider()
+
+            ScrollableDataTableView(
+                dataTable: dataTable,
+                showAlternatingRows: true,
+                showFooter: true
+            )
+            .frame(maxHeight: maxTableHeight)
+        }
+    }
+
+    // MARK: - Chart Section
+
+    @ViewBuilder
+    private func chartSection(for dataTable: DataTable) -> some View {
+        let detector = Self.chartDetector
+        if detector.detect(dataTable) != nil {
+            VStack(alignment: .leading, spacing: 4) {
+                ChartResultView(dataTable: dataTable, detector: detector)
+                    .frame(maxHeight: maxChartHeight)
+            }
+        }
+    }
+
+    // MARK: - SQL Disclosure
+
+    @ViewBuilder
+    private func sqlDisclosure(sql: String) -> some View {
+        DisclosureGroup {
+            Text(sql)
+                .font(.system(.caption, design: .monospaced))
+                .foregroundStyle(.secondary)
+                .textSelection(.enabled)
+                .padding(8)
+                .frame(maxWidth: .infinity, alignment: .leading)
+                .background(Color.primary.opacity(0.04))
+                .clipShape(RoundedRectangle(cornerRadius: 6))
+        } label: {
+            Label("SQL Query", systemImage: "chevron.left.forwardslash.chevron.right")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+        }
+    }
+
+    // MARK: - Styling Helpers
+
+    private var bubbleShape: RoundedRectangle {
+        RoundedRectangle(cornerRadius: 16, style: .continuous)
+    }
+
+    @ViewBuilder
+    private var bubbleBackground: some View {
+        switch message.role {
+        case .user:
+            Color.accentColor
+        case .assistant:
+            Self.assistantBackgroundColor
+        case .error:
+            Color.red.opacity(0.1)
+        }
+    }
+
+    private static var assistantBackgroundColor: Color {
+        #if os(macOS)
+        Color(nsColor: .controlBackgroundColor)
+        #else
+        Color(uiColor: .secondarySystemGroupedBackground)
+        #endif
+    }
+}

Sources/SwiftDBAI/Views/ScrollableDataTableView.swift

@@ -0,0 +1,267 @@
+// ScrollableDataTableView.swift
+// SwiftDBAI
+//
+// A SwiftUI view that renders a DataTable with horizontal and vertical
+// scrolling, styled column headers, and row cells.
+
+import SwiftUI
+
+/// A scrollable table view that renders a `DataTable` with column headers
+/// and row cells, supporting both horizontal and vertical scrolling.
+///
+/// Usage:
+/// ```swift
+/// ScrollableDataTableView(dataTable: myDataTable)
+/// ```
+///
+/// The view automatically sizes columns based on content, highlights
+/// alternating rows for readability, and right-aligns numeric columns.
+public struct ScrollableDataTableView: View {
+    /// The data table to render.
+    public let dataTable: DataTable
+
+    /// Minimum width for each column in points.
+    public var minimumColumnWidth: CGFloat
+
+    /// Maximum width for each column in points.
+    public var maximumColumnWidth: CGFloat
+
+    /// Whether to show alternating row backgrounds.
+    public var showAlternatingRows: Bool
+
+    /// Whether to show the row count footer.
+    public var showFooter: Bool
+
+    public init(
+        dataTable: DataTable,
+        minimumColumnWidth: CGFloat = 80,
+        maximumColumnWidth: CGFloat = 250,
+        showAlternatingRows: Bool = true,
+        showFooter: Bool = true
+    ) {
+        self.dataTable = dataTable
+        self.minimumColumnWidth = minimumColumnWidth
+        self.maximumColumnWidth = maximumColumnWidth
+        self.showAlternatingRows = showAlternatingRows
+        self.showFooter = showFooter
+    }
+
+    public var body: some View {
+        if dataTable.isEmpty {
+            emptyView
+        } else {
+            tableContent
+        }
+    }
+
+    // MARK: - Empty State
+
+    @ViewBuilder
+    private var emptyView: some View {
+        VStack(spacing: 8) {
+            Image(systemName: "tablecells")
+                .font(.largeTitle)
+                .foregroundStyle(.secondary)
+            Text("No results")
+                .font(.headline)
+                .foregroundStyle(.secondary)
+        }
+        .frame(maxWidth: .infinity, minHeight: 100)
+    }
+
+    // MARK: - Table Content
+
+    @ViewBuilder
+    private var tableContent: some View {
+        VStack(alignment: .leading, spacing: 0) {
+            ScrollView([.horizontal, .vertical]) {
+                LazyVStack(alignment: .leading, spacing: 0, pinnedViews: [.sectionHeaders]) {
+                    Section {
+                        ForEach(dataTable.rows) { row in
+                            rowView(row)
+                        }
+                    } header: {
+                        headerRow
+                    }
+                }
+            }
+
+            if showFooter {
+                footerView
+            }
+        }
+    }
+
+    // MARK: - Header
+
+    @ViewBuilder
+    private var headerRow: some View {
+        HStack(spacing: 0) {
+            ForEach(dataTable.columns) { column in
+                Text(column.name)
+                    .font(.caption.weight(.semibold))
+                    .foregroundStyle(.primary)
+                    .lineLimit(1)
+                    .frame(
+                        width: columnWidth(for: column),
+                        alignment: alignment(for: column)
+                    )
+                    .padding(.horizontal, 8)
+                    .padding(.vertical, 6)
+
+                if column.index < dataTable.columnCount - 1 {
+                    Divider()
+                }
+            }
+        }
+        .background(.bar)
+        .overlay(alignment: .bottom) {
+            Divider()
+        }
+    }
+
+    // MARK: - Row
+
+    @ViewBuilder
+    private func rowView(_ row: DataTable.Row) -> some View {
+        HStack(spacing: 0) {
+            ForEach(dataTable.columns) { column in
+                cellView(value: row[column.index], column: column)
+
+                if column.index < dataTable.columnCount - 1 {
+                    Divider()
+                }
+            }
+        }
+        .background(rowBackground(for: row))
+        .overlay(alignment: .bottom) {
+            Divider()
+        }
+    }
+
+    // MARK: - Cell
+
+    @ViewBuilder
+    private func cellView(value: QueryResult.Value, column: DataTable.Column) -> some View {
+        Group {
+            switch value {
+            case .null:
+                Text("NULL")
+                    .foregroundStyle(.tertiary)
+                    .italic()
+            case .blob(let data):
+                Text("<\(data.count) bytes>")
+                    .foregroundStyle(.secondary)
+            default:
+                Text(value.stringValue)
+                    .foregroundStyle(.primary)
+            }
+        }
+        .font(.caption)
+        .lineLimit(2)
+        .frame(
+            width: columnWidth(for: column),
+            alignment: alignment(for: column)
+        )
+        .padding(.horizontal, 8)
+        .padding(.vertical, 4)
+    }
+
+    // MARK: - Footer
+
+    @ViewBuilder
+    private var footerView: some View {
+        HStack {
+            Text("\(dataTable.rowCount) row\(dataTable.rowCount == 1 ? "" : "s")")
+                .font(.caption2)
+                .foregroundStyle(.secondary)
+            Spacer()
+            if dataTable.executionTime > 0 {
+                Text(String(format: "%.1f ms", dataTable.executionTime * 1000))
+                    .font(.caption2)
+                    .foregroundStyle(.secondary)
+            }
+        }
+        .padding(.horizontal, 8)
+        .padding(.vertical, 4)
+        .background(.bar)
+    }
+
+    // MARK: - Layout Helpers
+
+    /// Determines column width based on the column name length and type.
+    private func columnWidth(for column: DataTable.Column) -> CGFloat {
+        // Estimate based on header text length
+        let headerWidth = CGFloat(column.name.count) * 8 + 16
+
+        // Sample some row values to estimate content width
+        let sampleRows = dataTable.rows.prefix(20)
+        let maxContentWidth = sampleRows.reduce(CGFloat(0)) { maxWidth, row in
+            let value = row[column.index]
+            let textLength = CGFloat(value.stringValue.count) * 7
+            return max(maxWidth, textLength)
+        }
+
+        let estimatedWidth = max(headerWidth, maxContentWidth) + 16
+        return min(max(estimatedWidth, minimumColumnWidth), maximumColumnWidth)
+    }
+
+    /// Returns the alignment for a column based on its inferred type.
+    private func alignment(for column: DataTable.Column) -> Alignment {
+        switch column.inferredType {
+        case .integer, .real:
+            return .trailing
+        default:
+            return .leading
+        }
+    }
+
+    /// Returns the background color for alternating rows.
+    @ViewBuilder
+    private func rowBackground(for row: DataTable.Row) -> some View {
+        if showAlternatingRows && row.id.isMultiple(of: 2) {
+            Color.clear
+        } else if showAlternatingRows {
+            Color.primary.opacity(0.03)
+        } else {
+            Color.clear
+        }
+    }
+}
+
+// MARK: - Preview Support
+
+#if DEBUG
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+#Preview("Data Table") {
+    let columns: [DataTable.Column] = [
+        .init(name: "id", index: 0, inferredType: .integer),
+        .init(name: "name", index: 1, inferredType: .text),
+        .init(name: "score", index: 2, inferredType: .real),
+    ]
+    let rows: [DataTable.Row] = (0..<25).map { i in
+        DataTable.Row(
+            id: i,
+            values: [
+                .integer(Int64(i + 1)),
+                .text("Item \(i + 1)"),
+                .real(Double.random(in: 1.0...100.0)),
+            ],
+            columnNames: ["id", "name", "score"]
+        )
+    }
+    let table = DataTable(columns: columns, rows: rows, sql: "SELECT * FROM items", executionTime: 0.023)
+
+    ScrollableDataTableView(dataTable: table)
+        .frame(height: 400)
+        .padding()
+}
+
+@available(iOS 17.0, macOS 14.0, visionOS 1.0, *)
+#Preview("Empty Table") {
+    let table = DataTable(columns: [], rows: [], sql: "", executionTime: 0)
+    ScrollableDataTableView(dataTable: table)
+        .frame(height: 200)
+        .padding()
+}
+#endif

Tests/SwiftDBAITests/BinarySizeTests.swift

@@ -0,0 +1,254 @@
+// BinarySizeTests.swift
+// SwiftDBAI
+//
+// Validates that the SwiftDBAI package stays within its 2 MB binary size budget.
+// This test suite uses source-level heuristics since we can't measure the actual
+// compiled binary size in a unit test. The constraints ensure the package remains
+// lightweight by checking:
+//   1. Total source code size (proxy for compiled size)
+//   2. No embedded binary assets or large resources
+//   3. No unnecessary heavy dependencies
+//   4. File count stays reasonable (no code bloat)
+
+import Foundation
+import Testing
+
+@Suite("Binary Size Budget")
+struct BinarySizeTests {
+
+    /// The maximum allowed total source code size in bytes.
+    /// At typical Swift optimized compilation ratios (2-4x), 500 KB of source
+    /// compiles to roughly 1-2 MB of binary. We set the source budget at 500 KB
+    /// to keep the compiled output well under 2 MB.
+    private static let maxSourceSizeBytes: Int = 500_000 // 500 KB
+
+    /// Maximum number of Swift source files allowed.
+    /// More files generally means more code and larger binaries.
+    private static let maxSourceFileCount: Int = 60
+
+    /// Maximum size for any single source file in bytes.
+    /// Large individual files often indicate code that should be split or
+    /// contains embedded data that bloats the binary.
+    private static let maxSingleFileSizeBytes: Int = 50_000 // 50 KB
+
+    /// Disallowed file extensions in the Sources directory that would bloat the binary.
+    private static let disallowedExtensions: Set<String> = [
+        "png", "jpg", "jpeg", "gif", "bmp", "tiff",
+        "mp3", "mp4", "wav", "mov",
+        "mlmodel", "mlmodelc", "mlpackage",
+        "sqlite", "db",
+        "zip", "tar", "gz",
+        "bin", "dat",
+        "framework", "dylib", "a"
+    ]
+
+    // MARK: - Helper
+
+    /// Recursively finds all files in the Sources/SwiftDBAI directory.
+    private func findSourceFiles() throws -> [URL] {
+        let sourcesDir = findSourcesDirectory()
+        guard let sourcesDir else {
+            Issue.record("Could not locate Sources/SwiftDBAI directory")
+            return []
+        }
+
+        let fileManager = FileManager.default
+        guard let enumerator = fileManager.enumerator(
+            at: sourcesDir,
+            includingPropertiesForKeys: [.fileSizeKey, .isRegularFileKey],
+            options: [.skipsHiddenFiles]
+        ) else {
+            Issue.record("Could not enumerate Sources/SwiftDBAI directory")
+            return []
+        }
+
+        var files: [URL] = []
+        for case let fileURL as URL in enumerator {
+            let resourceValues = try fileURL.resourceValues(forKeys: [.isRegularFileKey])
+            if resourceValues.isRegularFile == true {
+                files.append(fileURL)
+            }
+        }
+        return files
+    }
+
+    /// Locates the Sources/SwiftDBAI directory by walking up from the test bundle.
+    private func findSourcesDirectory() -> URL? {
+        // Try common locations relative to the build directory
+        let fileManager = FileManager.default
+
+        // In SPM test runs, we can find the package root by checking known paths
+        var candidateURL = URL(fileURLWithPath: #filePath)
+        // Walk up from Tests/SwiftDBAITests/BinarySizeTests.swift to package root
+        for _ in 0..<3 {
+            candidateURL = candidateURL.deletingLastPathComponent()
+        }
+        let sourcesDir = candidateURL.appendingPathComponent("Sources/SwiftDBAI")
+        if fileManager.fileExists(atPath: sourcesDir.path) {
+            return sourcesDir
+        }
+
+        // Fallback: check current working directory
+        let cwdSources = URL(fileURLWithPath: fileManager.currentDirectoryPath)
+            .appendingPathComponent("Sources/SwiftDBAI")
+        if fileManager.fileExists(atPath: cwdSources.path) {
+            return cwdSources
+        }
+
+        return nil
+    }
+
+    // MARK: - Tests
+
+    @Test("Total source code size stays under 500 KB budget")
+    func totalSourceCodeSizeUnderBudget() throws {
+        let files = try findSourceFiles()
+        let swiftFiles = files.filter { $0.pathExtension == "swift" }
+
+        var totalSize: Int = 0
+        for file in swiftFiles {
+            let attributes = try FileManager.default.attributesOfItem(atPath: file.path)
+            let fileSize = attributes[.size] as? Int ?? 0
+            totalSize += fileSize
+        }
+
+        #expect(totalSize < Self.maxSourceSizeBytes,
+            """
+            Total Swift source size (\(totalSize) bytes) exceeds \(Self.maxSourceSizeBytes) byte budget.
+            At typical 2-4x compilation ratio, this would produce a binary larger than 2 MB.
+            Consider removing unused code or splitting into optional sub-targets.
+            """)
+
+        // Log the actual size for visibility
+        let sizeKB = Double(totalSize) / 1024.0
+        let budgetKB = Double(Self.maxSourceSizeBytes) / 1024.0
+        print("📦 SwiftDBAI source size: \(String(format: "%.1f", sizeKB)) KB / \(String(format: "%.0f", budgetKB)) KB budget (\(String(format: "%.0f", (sizeKB / budgetKB) * 100))% used)")
+    }
+
+    @Test("Source file count stays reasonable")
+    func sourceFileCountUnderLimit() throws {
+        let files = try findSourceFiles()
+        let swiftFiles = files.filter { $0.pathExtension == "swift" }
+
+        #expect(swiftFiles.count <= Self.maxSourceFileCount,
+            """
+            Swift source file count (\(swiftFiles.count)) exceeds limit of \(Self.maxSourceFileCount).
+            More files generally means more code and larger binaries.
+            """)
+
+        print("📦 SwiftDBAI file count: \(swiftFiles.count) / \(Self.maxSourceFileCount) max")
+    }
+
+    @Test("No individual source file exceeds 50 KB")
+    func noOversizedSourceFiles() throws {
+        let files = try findSourceFiles()
+        let swiftFiles = files.filter { $0.pathExtension == "swift" }
+
+        for file in swiftFiles {
+            let attributes = try FileManager.default.attributesOfItem(atPath: file.path)
+            let fileSize = attributes[.size] as? Int ?? 0
+
+            #expect(fileSize < Self.maxSingleFileSizeBytes,
+                """
+                File \(file.lastPathComponent) is \(fileSize) bytes, exceeding the \(Self.maxSingleFileSizeBytes) byte limit.
+                Large files may contain embedded data or code that should be split.
+                """)
+        }
+    }
+
+    @Test("No binary assets or heavy resources in Sources directory")
+    func noBinaryAssetsInSources() throws {
+        let files = try findSourceFiles()
+
+        let disallowedFiles = files.filter { file in
+            Self.disallowedExtensions.contains(file.pathExtension.lowercased())
+        }
+
+        #expect(disallowedFiles.isEmpty,
+            """
+            Found \(disallowedFiles.count) disallowed file(s) in Sources directory:
+            \(disallowedFiles.map(\.lastPathComponent).joined(separator: "\n"))
+            These file types bloat the binary. Remove them or move to a separate resource bundle.
+            """)
+    }
+
+    @Test("Package has no resource bundles that could bloat binary")
+    func noResourceBundles() throws {
+        let files = try findSourceFiles()
+
+        let resourceFiles = files.filter { file in
+            let ext = file.pathExtension.lowercased()
+            return ["xcassets", "storyboard", "xib", "nib", "xcdatamodeld"].contains(ext)
+        }
+
+        #expect(resourceFiles.isEmpty,
+            """
+            Found resource bundle files that could bloat the binary:
+            \(resourceFiles.map(\.lastPathComponent).joined(separator: "\n"))
+            SwiftDBAI should be pure code — no bundled resources.
+            """)
+    }
+
+    @Test("Only expected dependencies declared (GRDB + AnyLanguageModel)")
+    func minimalDependencies() throws {
+        // Read Package.swift to verify we only have the expected dependencies
+        var packageURL = URL(fileURLWithPath: #filePath)
+        for _ in 0..<3 {
+            packageURL = packageURL.deletingLastPathComponent()
+        }
+        let packageSwiftURL = packageURL.appendingPathComponent("Package.swift")
+
+        guard FileManager.default.fileExists(atPath: packageSwiftURL.path) else {
+            // Skip if we can't find Package.swift (CI environments etc.)
+            return
+        }
+
+        let packageContents = try String(contentsOf: packageSwiftURL, encoding: .utf8)
+
+        // Count .package() declarations (dependencies)
+        let packageDeclarations = packageContents.components(separatedBy: ".package(")
+            .count - 1 // subtract 1 because the first segment is before any .package(
+
+        #expect(packageDeclarations <= 2,
+            """
+            Found \(packageDeclarations) package dependencies, expected at most 2 (GRDB + AnyLanguageModel).
+            Additional dependencies increase binary size. Evaluate if they're truly needed.
+            """)
+
+        // Verify the expected dependencies are present
+        #expect(packageContents.contains("GRDB"), "Expected GRDB dependency")
+        #expect(packageContents.contains("AnyLanguageModel"), "Expected AnyLanguageModel dependency")
+
+        print("📦 SwiftDBAI dependencies: \(packageDeclarations) (GRDB + AnyLanguageModel)")
+    }
+
+    @Test("Estimated binary size under 2 MB")
+    func estimatedBinarySizeUnderLimit() throws {
+        let files = try findSourceFiles()
+        let swiftFiles = files.filter { $0.pathExtension == "swift" }
+
+        var totalSize: Int = 0
+        for file in swiftFiles {
+            let attributes = try FileManager.default.attributesOfItem(atPath: file.path)
+            let fileSize = attributes[.size] as? Int ?? 0
+            totalSize += fileSize
+        }
+
+        // Conservative estimate: optimized Swift binary is typically 2-4x source size.
+        // Use 4x as worst case multiplier for safety margin.
+        let worstCaseMultiplier = 4.0
+        let estimatedBinarySize = Double(totalSize) * worstCaseMultiplier
+        let maxBinarySize: Double = 2.0 * 1024.0 * 1024.0 // 2 MB
+
+        #expect(estimatedBinarySize < maxBinarySize,
+            """
+            Estimated binary size (\(String(format: "%.1f", estimatedBinarySize / 1024.0)) KB) exceeds 2 MB limit.
+            Source: \(totalSize) bytes × \(worstCaseMultiplier)x multiplier = \(String(format: "%.1f", estimatedBinarySize / 1024.0)) KB
+            Note: This is the SwiftDBAI module only — excludes GRDB and AnyLanguageModel
+            which are existing dependencies the developer already includes.
+            """)
+
+        let estimatedMB = estimatedBinarySize / (1024.0 * 1024.0)
+        print("📦 Estimated SwiftDBAI binary size: \(String(format: "%.2f", estimatedMB)) MB / 2.00 MB limit (worst case \(worstCaseMultiplier)x)")
+    }
+}

Tests/SwiftDBAITests/ChartDataDetectorTests.swift

@@ -0,0 +1,293 @@
+// ChartDataDetectorTests.swift
+// SwiftDBAITests
+
+import Testing
+@testable import SwiftDBAI
+
+@Suite("ChartDataDetector")
+struct ChartDataDetectorTests {
+
+    let detector = ChartDataDetector()
+
+    // MARK: - Helpers
+
+    private func makeQueryResult(
+        columns: [String],
+        rows: [[QueryResult.Value]],
+        sql: String = "SELECT *"
+    ) -> QueryResult {
+        let rowDicts = rows.map { values in
+            Dictionary(uniqueKeysWithValues: zip(columns, values))
+        }
+        return QueryResult(
+            columns: columns,
+            rows: rowDicts,
+            sql: sql,
+            executionTime: 0.01
+        )
+    }
+
+    private func makeTable(
+        columns: [String],
+        rows: [[QueryResult.Value]],
+        sql: String = "SELECT *"
+    ) -> DataTable {
+        DataTable(makeQueryResult(columns: columns, rows: rows, sql: sql))
+    }
+
+    // MARK: - Basic Eligibility
+
+    @Test("Returns nil for single-column results")
+    func singleColumn() {
+        let table = makeTable(
+            columns: ["count"],
+            rows: [[.integer(42)]]
+        )
+        #expect(detector.detect(table) == nil)
+    }
+
+    @Test("Returns nil for empty results")
+    func emptyResults() {
+        let table = makeTable(columns: ["name", "value"], rows: [])
+        #expect(detector.detect(table) == nil)
+    }
+
+    @Test("Returns nil for single row")
+    func singleRow() {
+        let table = makeTable(
+            columns: ["name", "count"],
+            rows: [[.text("A"), .integer(10)]]
+        )
+        #expect(detector.detect(table) == nil)
+    }
+
+    @Test("Returns nil for too many rows")
+    func tooManyRows() {
+        let rows = (0..<101).map { i in
+            [QueryResult.Value.text("cat\(i)"), .integer(Int64(i))]
+        }
+        let table = makeTable(columns: ["name", "count"], rows: rows)
+        #expect(detector.detect(table) == nil)
+    }
+
+    // MARK: - Bar Chart Detection
+
+    @Test("Recommends bar chart for categorical text + numeric")
+    func barChartCategorical() {
+        let table = makeTable(
+            columns: ["department", "headcount"],
+            rows: [
+                [.text("Engineering"), .integer(45)],
+                [.text("Marketing"), .integer(20)],
+                [.text("Sales"), .integer(30)],
+                [.text("HR"), .integer(10)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.chartType == .bar)
+        #expect(rec?.categoryColumn == "department")
+        #expect(rec?.valueColumn == "headcount")
+        #expect(rec?.confidence ?? 0 > 0.5)
+    }
+
+    // MARK: - Pie Chart Detection
+
+    @Test("Recommends pie chart for small positive proportions")
+    func pieChartSmallCategories() {
+        let table = makeTable(
+            columns: ["status", "count"],
+            rows: [
+                [.text("Active"), .integer(50)],
+                [.text("Inactive"), .integer(30)],
+                [.text("Pending"), .integer(20)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.chartType == .pie)
+        #expect(rec?.categoryColumn == "status")
+        #expect(rec?.valueColumn == "count")
+    }
+
+    @Test("Does not recommend pie with negative values")
+    func pieRejectsNegative() {
+        let table = makeTable(
+            columns: ["category", "change"],
+            rows: [
+                [.text("A"), .integer(50)],
+                [.text("B"), .integer(-10)],
+                [.text("C"), .integer(20)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        // Should NOT be pie since there's a negative value
+        #expect(rec?.chartType != .pie)
+    }
+
+    @Test("Does not recommend pie with too many slices")
+    func pieRejectsTooManySlices() {
+        let rows = (0..<10).map { i in
+            [QueryResult.Value.text("cat\(i)"), .integer(Int64(i + 1))]
+        }
+        let table = makeTable(columns: ["category", "value"], rows: rows)
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.chartType != .pie)
+    }
+
+    // MARK: - Line Chart Detection
+
+    @Test("Recommends line chart for time-series column names")
+    func lineChartTimeSeries() {
+        let table = makeTable(
+            columns: ["year", "revenue"],
+            rows: [
+                [.text("2020"), .real(1_000_000)],
+                [.text("2021"), .real(1_200_000)],
+                [.text("2022"), .real(1_500_000)],
+                [.text("2023"), .real(1_800_000)],
+                [.text("2024"), .real(2_100_000)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.chartType == .line)
+        #expect(rec?.categoryColumn == "year")
+        #expect(rec?.valueColumn == "revenue")
+    }
+
+    @Test("Recommends line chart for date-formatted text values")
+    func lineChartDateValues() {
+        let table = makeTable(
+            columns: ["period", "sales"],
+            rows: [
+                [.text("2024-01"), .integer(100)],
+                [.text("2024-02"), .integer(120)],
+                [.text("2024-03"), .integer(90)],
+                [.text("2024-04"), .integer(150)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.chartType == .line)
+    }
+
+    @Test("Recommends line chart for sequential numeric x-axis")
+    func lineChartSequential() {
+        let table = makeTable(
+            columns: ["step", "value"],
+            rows: [
+                [.integer(1), .real(2.5)],
+                [.integer(2), .real(3.1)],
+                [.integer(3), .real(4.0)],
+                [.integer(4), .real(3.8)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.chartType == .line)
+    }
+
+    // MARK: - All Recommendations
+
+    @Test("Returns multiple recommendations sorted by confidence")
+    func allRecommendations() {
+        let table = makeTable(
+            columns: ["category", "amount"],
+            rows: [
+                [.text("A"), .integer(30)],
+                [.text("B"), .integer(50)],
+                [.text("C"), .integer(20)],
+            ]
+        )
+        let recs = detector.allRecommendations(for: table)
+        #expect(!recs.isEmpty)
+        // Should be sorted by confidence descending
+        for i in 1..<recs.count {
+            #expect(recs[i - 1].confidence >= recs[i].confidence)
+        }
+    }
+
+    // MARK: - Two Numeric Columns Fallback
+
+    @Test("Uses first numeric as category when no text column exists")
+    func numericOnlyColumns() {
+        let table = makeTable(
+            columns: ["x", "y"],
+            rows: [
+                [.integer(1), .integer(10)],
+                [.integer(2), .integer(20)],
+                [.integer(3), .integer(30)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec?.categoryColumn == "x")
+        #expect(rec?.valueColumn == "y")
+    }
+
+    // MARK: - Confidence & Reason
+
+    @Test("Confidence is between 0 and 1")
+    func confidenceBounds() {
+        let table = makeTable(
+            columns: ["name", "score"],
+            rows: [
+                [.text("A"), .integer(10)],
+                [.text("B"), .integer(20)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(rec!.confidence >= 0.0)
+        #expect(rec!.confidence <= 1.0)
+    }
+
+    @Test("Reason is non-empty")
+    func reasonPresent() {
+        let table = makeTable(
+            columns: ["name", "score"],
+            rows: [
+                [.text("A"), .integer(10)],
+                [.text("B"), .integer(20)],
+            ]
+        )
+        let rec = detector.detect(table)
+        #expect(rec != nil)
+        #expect(!rec!.reason.isEmpty)
+    }
+
+    // MARK: - Custom Configuration
+
+    @Test("Respects custom minimumRows")
+    func customMinRows() {
+        let strict = ChartDataDetector(minimumRows: 5)
+        let table = makeTable(
+            columns: ["name", "value"],
+            rows: [
+                [.text("A"), .integer(1)],
+                [.text("B"), .integer(2)],
+                [.text("C"), .integer(3)],
+            ]
+        )
+        #expect(strict.detect(table) == nil)
+    }
+
+    @Test("Respects custom maxPieSlices")
+    func customMaxPieSlices() {
+        let narrow = ChartDataDetector(maxPieSlices: 2)
+        let table = makeTable(
+            columns: ["status", "count"],
+            rows: [
+                [.text("A"), .integer(50)],
+                [.text("B"), .integer(30)],
+                [.text("C"), .integer(20)],
+            ]
+        )
+        let rec = narrow.detect(table)
+        // With maxPieSlices=2, 3 rows should not get pie
+        #expect(rec?.chartType != .pie)
+    }
+}

Tests/SwiftDBAITests/ChatViewTests.swift

@@ -0,0 +1,164 @@
+// ChatViewTests.swift
+// SwiftDBAITests
+//
+// Tests for ChatView, ChatViewModel, and MessageBubbleView integration
+// with ScrollableDataTableView.
+
+import Testing
+import Foundation
+@testable import SwiftDBAI
+
+@Suite("SchemaReadiness Tests")
+struct SchemaReadinessTests {
+
+    @Test("SchemaReadiness isReady returns true only for ready state")
+    func isReadyProperty() {
+        #expect(SchemaReadiness.idle.isReady == false)
+        #expect(SchemaReadiness.loading.isReady == false)
+        #expect(SchemaReadiness.ready(tableCount: 3).isReady == true)
+        #expect(SchemaReadiness.failed("error").isReady == false)
+    }
+}
+
+@Suite("ChatViewModel Tests")
+struct ChatViewModelTests {
+
+    @Test("Messages with query results produce DataTable-compatible data")
+    func messageWithQueryResultHasTableData() {
+        // A ChatMessage with a queryResult should have the data needed
+        // for ScrollableDataTableView rendering
+        let result = QueryResult(
+            columns: ["id", "name", "score"],
+            rows: [
+                ["id": .integer(1), "name": .text("Alice"), "score": .real(95.5)],
+                ["id": .integer(2), "name": .text("Bob"), "score": .real(87.3)],
+            ],
+            sql: "SELECT id, name, score FROM users",
+            executionTime: 0.01
+        )
+
+        let message = ChatMessage(
+            role: .assistant,
+            content: "Found 2 users.",
+            queryResult: result,
+            sql: "SELECT id, name, score FROM users"
+        )
+
+        // Verify queryResult is present and can be converted to DataTable
+        #expect(message.queryResult != nil)
+        #expect(message.queryResult!.columns.count == 3)
+        #expect(message.queryResult!.rows.count == 2)
+
+        // Verify DataTable conversion works (this is what MessageBubbleView does)
+        let dataTable = DataTable(message.queryResult!)
+        #expect(dataTable.columnCount == 3)
+        #expect(dataTable.rowCount == 2)
+        #expect(dataTable.columns[0].name == "id")
+        #expect(dataTable.columns[1].name == "name")
+        #expect(dataTable.columns[2].name == "score")
+    }
+
+    @Test("Messages without query results do not trigger table rendering")
+    func messageWithoutQueryResult() {
+        let message = ChatMessage(
+            role: .assistant,
+            content: "Hello! How can I help?",
+            queryResult: nil,
+            sql: nil
+        )
+
+        #expect(message.queryResult == nil)
+    }
+
+    @Test("Empty query results do not trigger table rendering")
+    func emptyQueryResult() {
+        let result = QueryResult(
+            columns: [],
+            rows: [],
+            sql: "SELECT * FROM empty_table",
+            executionTime: 0.001
+        )
+
+        let message = ChatMessage(
+            role: .assistant,
+            content: "No results found.",
+            queryResult: result,
+            sql: "SELECT * FROM empty_table"
+        )
+
+        // Even though queryResult exists, it has no columns/rows
+        // MessageBubbleView checks both conditions before showing the table
+        #expect(message.queryResult != nil)
+        #expect(message.queryResult!.columns.isEmpty)
+        #expect(message.queryResult!.rows.isEmpty)
+    }
+
+    @Test("Mutation results do not trigger table rendering")
+    func mutationQueryResult() {
+        let result = QueryResult(
+            columns: [],
+            rows: [],
+            sql: "INSERT INTO users (name) VALUES ('Charlie')",
+            executionTime: 0.005,
+            rowsAffected: 1
+        )
+
+        let message = ChatMessage(
+            role: .assistant,
+            content: "Successfully inserted 1 row.",
+            queryResult: result,
+            sql: "INSERT INTO users (name) VALUES ('Charlie')"
+        )
+
+        // Mutation results have empty columns — no table shown
+        #expect(message.queryResult!.columns.isEmpty)
+    }
+
+    @Test("Error messages never have query results")
+    func errorMessageHasNoQueryResult() {
+        let message = ChatMessage(
+            role: .error,
+            content: "SELECT operations are not allowed."
+        )
+
+        #expect(message.queryResult == nil)
+        #expect(message.role == .error)
+    }
+
+    @Test("DataTable preserves column order from QueryResult")
+    func dataTableColumnOrder() {
+        let result = QueryResult(
+            columns: ["date", "revenue", "category"],
+            rows: [
+                ["date": .text("2024-01-01"), "revenue": .real(1500.0), "category": .text("Electronics")],
+            ],
+            sql: "SELECT date, revenue, category FROM sales",
+            executionTime: 0.02
+        )
+
+        let dataTable = DataTable(result)
+        #expect(dataTable.columnNames == ["date", "revenue", "category"])
+    }
+
+    @Test("Large result sets are renderable as DataTable")
+    func largeResultSet() {
+        var rows: [[String: QueryResult.Value]] = []
+        for i in 0..<500 {
+            rows.append([
+                "id": .integer(Int64(i)),
+                "value": .real(Double(i) * 1.5),
+            ])
+        }
+
+        let result = QueryResult(
+            columns: ["id", "value"],
+            rows: rows,
+            sql: "SELECT id, value FROM big_table",
+            executionTime: 0.15
+        )
+
+        let dataTable = DataTable(result)
+        #expect(dataTable.rowCount == 500)
+        #expect(dataTable.columnCount == 2)
+    }
+}

Tests/SwiftDBAITests/DataChatViewUsageTests.swift

@@ -0,0 +1,136 @@
+// DataChatViewUsageTests.swift
+// SwiftDBAITests
+//
+// Proves DataChatView works with minimal setup — under 10 lines of code.
+// A developer only needs a GRDB connection and a LanguageModel to get a
+// full chat-with-database SwiftUI view.
+
+import Testing
+import Foundation
+import GRDB
+@testable import SwiftDBAI
+
+// MARK: - Minimal Setup: DataChatView in Under 10 Lines
+
+/// This test suite proves the "zero_config_reads" principle:
+/// A developer with an existing SQLite database can create a fully functional
+/// chat UI by providing only a GRDB connection and a language model instance.
+/// No schema files, no annotations, no manual configuration required.
+@Suite("DataChatView Minimal Setup")
+struct DataChatViewMinimalSetupTests {
+
+    // ┌──────────────────────────────────────────────────────────┐
+    // │  USAGE EXAMPLE — DataChatView in 6 lines of real code   │
+    // │                                                          │
+    // │  import SwiftDBAI                                        │
+    // │  import GRDB                                             │
+    // │                                                          │
+    // │  let db = try DatabaseQueue(path: "mydata.sqlite")       │
+    // │  let model = OllamaLanguageModel(model: "llama3")        │
+    // │                                                          │
+    // │  var body: some View {                                   │
+    // │      DataChatView(database: db, model: model)            │
+    // │  }                                                       │
+    // └──────────────────────────────────────────────────────────┘
+
+    /// Creates a temporary in-memory database with sample data for tests.
+    private static func makeSampleDatabase() throws -> DatabaseQueue {
+        let db = try DatabaseQueue()
+        try db.write { db in
+            try db.execute(sql: """
+                CREATE TABLE products (
+                    id INTEGER PRIMARY KEY,
+                    name TEXT NOT NULL,
+                    price REAL NOT NULL,
+                    category TEXT
+                );
+                INSERT INTO products (name, price, category) VALUES ('Widget', 9.99, 'Hardware');
+                INSERT INTO products (name, price, category) VALUES ('Gadget', 24.99, 'Electronics');
+                INSERT INTO products (name, price, category) VALUES ('Doohickey', 4.99, 'Hardware');
+                """)
+        }
+        return db
+    }
+
+    @Test("DataChatView initializes from database + model in 2 lines")
+    @MainActor
+    func dataChatViewMinimalInit() throws {
+        // LINE 1: Create (or receive) a GRDB connection
+        let db = try Self.makeSampleDatabase()
+        // LINE 2: Create the view — that's it!
+        let _ = DataChatView(database: db, model: MockLanguageModel())
+        // The view is ready. No schema files, no annotations, no extra config.
+    }
+
+    @Test("DataChatView path-based init works in 1 line given a path and model")
+    @MainActor
+    func dataChatViewPathInit() throws {
+        // Create a temp database file
+        let tempDir = FileManager.default.temporaryDirectory
+        let dbPath = tempDir.appendingPathComponent("test_\(UUID().uuidString).sqlite").path
+        let db = try DatabaseQueue(path: dbPath)
+        try db.write { db in
+            try db.execute(sql: "CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)")
+        }
+
+        // ONE LINE to get a full chat UI:
+        let _ = DataChatView(databasePath: dbPath, model: MockLanguageModel())
+
+        // Cleanup
+        try? FileManager.default.removeItem(atPath: dbPath)
+    }
+
+    @Test("ChatEngine headless usage works in 3 lines")
+    func chatEngineMinimalUsage() async throws {
+        // LINE 1: Database
+        let db = try Self.makeSampleDatabase()
+        // LINE 2: Engine
+        let engine = ChatEngine(database: db, model: MockLanguageModel(responseText: "SELECT COUNT(*) AS total FROM products"))
+        // LINE 3: Schema preparation verifies auto-introspection works
+        let schema = try await engine.prepareSchema()
+
+        // The engine auto-discovered the schema — no manual config needed
+        #expect(schema.tableNames.contains("products"))
+        #expect(schema.tableNames.count == 1)
+    }
+
+    @Test("ChatViewModel works with zero configuration beyond db + model")
+    @MainActor
+    func chatViewModelMinimalUsage() async throws {
+        let db = try Self.makeSampleDatabase()
+        let engine = ChatEngine(database: db, model: MockLanguageModel())
+        let viewModel = ChatViewModel(engine: engine)
+
+        // Prepare triggers auto-schema-introspection
+        await viewModel.prepare()
+
+        #expect(viewModel.schemaReadiness.isReady)
+        #expect(viewModel.messages.isEmpty) // Clean slate, ready to chat
+    }
+
+    @Test("Default configuration is read-only (safe by default)")
+    @MainActor
+    func defaultIsReadOnly() throws {
+        let db = try Self.makeSampleDatabase()
+        // No allowlist specified — defaults to .readOnly
+        let _ = DataChatView(database: db, model: MockLanguageModel())
+        // This compiles and works. SELECT-only is the safe default.
+        // Developer must explicitly opt in to writes:
+        // DataChatView(database: db, model: model, allowlist: .standard)
+    }
+
+    @Test("Full DataChatView with all options still under 10 lines")
+    @MainActor
+    func dataChatViewFullConfig() throws {
+        let db = try Self.makeSampleDatabase()                          // 1
+        let model = MockLanguageModel()                                  // 2
+        let _ = DataChatView(                                            // 3-8
+            database: db,
+            model: model,
+            allowlist: .readOnly,
+            additionalContext: "Product catalog for an e-commerce store",
+            maxSummaryRows: 100
+        )
+        // Even with ALL options specified, it's under 10 lines of setup.
+    }
+}

Tests/SwiftDBAITests/DataTableTests.swift

@@ -0,0 +1,285 @@
+// DataTableTests.swift
+// SwiftDBAITests
+
+import Foundation
+import Testing
+@testable import SwiftDBAI
+
+@Suite("DataTable")
+struct DataTableTests {
+
+    // MARK: - Helpers
+
+    private func makeQueryResult(
+        columns: [String],
+        rows: [[String: QueryResult.Value]],
+        sql: String = "SELECT * FROM test",
+        executionTime: TimeInterval = 0.01
+    ) -> QueryResult {
+        QueryResult(
+            columns: columns,
+            rows: rows,
+            sql: sql,
+            executionTime: executionTime
+        )
+    }
+
+    // MARK: - Basic Construction
+
+    @Test("Converts QueryResult columns and rows correctly")
+    func basicConversion() {
+        let result = makeQueryResult(
+            columns: ["id", "name", "score"],
+            rows: [
+                ["id": .integer(1), "name": .text("Alice"), "score": .real(95.5)],
+                ["id": .integer(2), "name": .text("Bob"), "score": .real(87.0)],
+            ]
+        )
+
+        let table = DataTable(result)
+
+        #expect(table.columnCount == 3)
+        #expect(table.rowCount == 2)
+        #expect(table.columnNames == ["id", "name", "score"])
+        #expect(table.sql == "SELECT * FROM test")
+        #expect(table.executionTime == 0.01)
+    }
+
+    @Test("Empty result produces empty table")
+    func emptyResult() {
+        let result = makeQueryResult(columns: ["id", "name"], rows: [])
+
+        let table = DataTable(result)
+
+        #expect(table.isEmpty)
+        #expect(table.rowCount == 0)
+        #expect(table.columnCount == 2)
+        #expect(table.columnNames == ["id", "name"])
+    }
+
+    // MARK: - Subscript Access
+
+    @Test("Subscript by row and column index")
+    func subscriptByIndex() {
+        let result = makeQueryResult(
+            columns: ["a", "b"],
+            rows: [
+                ["a": .integer(10), "b": .text("hello")],
+                ["a": .integer(20), "b": .text("world")],
+            ]
+        )
+
+        let table = DataTable(result)
+
+        #expect(table[row: 0, column: 0] == .integer(10))
+        #expect(table[row: 0, column: 1] == .text("hello"))
+        #expect(table[row: 1, column: 0] == .integer(20))
+        #expect(table[row: 1, column: 1] == .text("world"))
+    }
+
+    @Test("Subscript by row index and column name")
+    func subscriptByName() {
+        let result = makeQueryResult(
+            columns: ["x", "y"],
+            rows: [["x": .real(1.5), "y": .real(2.5)]]
+        )
+
+        let table = DataTable(result)
+
+        #expect(table[row: 0, column: "x"] == .real(1.5))
+        #expect(table[row: 0, column: "y"] == .real(2.5))
+        #expect(table[row: 0, column: "z"] == .null) // non-existent column
+    }
+
+    // MARK: - Column Data Extraction
+
+    @Test("Extract column values by index")
+    func columnValuesByIndex() {
+        let result = makeQueryResult(
+            columns: ["val"],
+            rows: [
+                ["val": .integer(1)],
+                ["val": .integer(2)],
+                ["val": .integer(3)],
+            ]
+        )
+
+        let table = DataTable(result)
+        let values = table.columnValues(at: 0)
+
+        #expect(values == [.integer(1), .integer(2), .integer(3)])
+    }
+
+    @Test("Extract column values by name")
+    func columnValuesByName() {
+        let result = makeQueryResult(
+            columns: ["name"],
+            rows: [
+                ["name": .text("A")],
+                ["name": .text("B")],
+            ]
+        )
+
+        let table = DataTable(result)
+
+        #expect(table.columnValues(named: "name") == [.text("A"), .text("B")])
+        #expect(table.columnValues(named: "missing").isEmpty)
+    }
+
+    @Test("numericValues extracts doubles from numeric column")
+    func numericValues() {
+        let result = makeQueryResult(
+            columns: ["score"],
+            rows: [
+                ["score": .integer(10)],
+                ["score": .real(20.5)],
+                ["score": .null],
+                ["score": .text("not a number")],
+            ]
+        )
+
+        let table = DataTable(result)
+        let nums = table.numericValues(forColumn: "score")
+
+        #expect(nums.count == 2)
+        #expect(nums[0] == 10.0)
+        #expect(nums[1] == 20.5)
+    }
+
+    @Test("stringValues extracts non-null strings")
+    func stringValues() {
+        let result = makeQueryResult(
+            columns: ["label"],
+            rows: [
+                ["label": .text("foo")],
+                ["label": .null],
+                ["label": .text("bar")],
+            ]
+        )
+
+        let table = DataTable(result)
+        let strs = table.stringValues(forColumn: "label")
+
+        #expect(strs == ["foo", "bar"])
+    }
+
+    // MARK: - Type Inference
+
+    @Test("Infers integer type for all-integer column")
+    func inferInteger() {
+        let result = makeQueryResult(
+            columns: ["id"],
+            rows: [["id": .integer(1)], ["id": .integer(2)]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .integer)
+    }
+
+    @Test("Infers real type for all-real column")
+    func inferReal() {
+        let result = makeQueryResult(
+            columns: ["price"],
+            rows: [["price": .real(1.99)], ["price": .real(2.50)]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .real)
+    }
+
+    @Test("Infers text type for all-text column")
+    func inferText() {
+        let result = makeQueryResult(
+            columns: ["name"],
+            rows: [["name": .text("A")], ["name": .text("B")]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .text)
+    }
+
+    @Test("Promotes integer + real to real")
+    func inferNumericPromotion() {
+        let result = makeQueryResult(
+            columns: ["val"],
+            rows: [["val": .integer(1)], ["val": .real(2.5)]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .real)
+    }
+
+    @Test("Mixed types result in .mixed")
+    func inferMixed() {
+        let result = makeQueryResult(
+            columns: ["data"],
+            rows: [["data": .integer(1)], ["data": .text("hello")]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .mixed)
+    }
+
+    @Test("All-null column infers .null")
+    func inferNull() {
+        let result = makeQueryResult(
+            columns: ["empty"],
+            rows: [["empty": .null], ["empty": .null]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .null)
+    }
+
+    @Test("Null values are ignored during type inference")
+    func inferIgnoresNulls() {
+        let result = makeQueryResult(
+            columns: ["val"],
+            rows: [["val": .integer(1)], ["val": .null], ["val": .integer(3)]]
+        )
+        let table = DataTable(result)
+        #expect(table.columns[0].inferredType == .integer)
+    }
+
+    // MARK: - Missing Values
+
+    @Test("Missing dictionary keys become .null")
+    func missingKeysBecomNull() {
+        let result = makeQueryResult(
+            columns: ["a", "b"],
+            rows: [["a": .integer(1)]] // "b" is missing
+        )
+
+        let table = DataTable(result)
+
+        #expect(table[row: 0, column: 0] == .integer(1))
+        #expect(table[row: 0, column: 1] == .null)
+    }
+
+    // MARK: - Row Identity
+
+    @Test("Rows have sequential IDs")
+    func rowIdentity() {
+        let result = makeQueryResult(
+            columns: ["x"],
+            rows: [["x": .integer(1)], ["x": .integer(2)], ["x": .integer(3)]]
+        )
+
+        let table = DataTable(result)
+
+        #expect(table.rows[0].id == 0)
+        #expect(table.rows[1].id == 1)
+        #expect(table.rows[2].id == 2)
+    }
+
+    // MARK: - Column Identity
+
+    @Test("Columns are Identifiable by name")
+    func columnIdentity() {
+        let result = makeQueryResult(
+            columns: ["alpha", "beta"],
+            rows: [["alpha": .integer(1), "beta": .integer(2)]]
+        )
+
+        let table = DataTable(result)
+
+        #expect(table.columns[0].id == "alpha")
+        #expect(table.columns[1].id == "beta")
+        #expect(table.columns[0].index == 0)
+        #expect(table.columns[1].index == 1)
+    }
+}

Tests/SwiftDBAITests/DestructiveOperationTests.swift

@@ -0,0 +1,745 @@
+// DestructiveOperationTests.swift
+// SwiftDBAITests
+//
+// Tests verifying that destructive operations are blocked without confirmation
+// and allowed when the delegate approves.
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+import Testing
+
+@testable import SwiftDBAI
+
+// MARK: - Test Delegates
+
+/// A delegate that always rejects destructive operations and tracks calls.
+private final class RejectingTrackingDelegate: SwiftDBAI.ToolExecutionDelegate, @unchecked Sendable {
+    private let lock = NSLock()
+    private var _confirmCalls: [DestructiveOperationContext] = []
+    private var _willExecuteCalls: [(sql: String, classification: DestructiveClassification)] = []
+    private var _didExecuteCalls: [(sql: String, success: Bool)] = []
+
+    var confirmCalls: [DestructiveOperationContext] {
+        lock.withLock { _confirmCalls }
+    }
+
+    var willExecuteCalls: [(sql: String, classification: DestructiveClassification)] {
+        lock.withLock { _willExecuteCalls }
+    }
+
+    var didExecuteCalls: [(sql: String, success: Bool)] {
+        lock.withLock { _didExecuteCalls }
+    }
+
+    func confirmDestructiveOperation(_ context: DestructiveOperationContext) async -> Bool {
+        lock.withLock { _confirmCalls.append(context) }
+        return false
+    }
+
+    func willExecuteSQL(_ sql: String, classification: DestructiveClassification) async {
+        lock.withLock { _willExecuteCalls.append((sql: sql, classification: classification)) }
+    }
+
+    func didExecuteSQL(_ sql: String, success: Bool) async {
+        lock.withLock { _didExecuteCalls.append((sql: sql, success: success)) }
+    }
+}
+
+/// A delegate that always approves destructive operations and tracks calls.
+private final class ApprovingTrackingDelegate: SwiftDBAI.ToolExecutionDelegate, @unchecked Sendable {
+    private let lock = NSLock()
+    private var _confirmCalls: [DestructiveOperationContext] = []
+    private var _willExecuteCalls: [(sql: String, classification: DestructiveClassification)] = []
+    private var _didExecuteCalls: [(sql: String, success: Bool)] = []
+
+    var confirmCalls: [DestructiveOperationContext] {
+        lock.withLock { _confirmCalls }
+    }
+
+    var willExecuteCalls: [(sql: String, classification: DestructiveClassification)] {
+        lock.withLock { _willExecuteCalls }
+    }
+
+    var didExecuteCalls: [(sql: String, success: Bool)] {
+        lock.withLock { _didExecuteCalls }
+    }
+
+    func confirmDestructiveOperation(_ context: DestructiveOperationContext) async -> Bool {
+        lock.withLock { _confirmCalls.append(context) }
+        return true
+    }
+
+    func willExecuteSQL(_ sql: String, classification: DestructiveClassification) async {
+        lock.withLock { _willExecuteCalls.append((sql: sql, classification: classification)) }
+    }
+
+    func didExecuteSQL(_ sql: String, success: Bool) async {
+        lock.withLock { _didExecuteCalls.append((sql: sql, success: success)) }
+    }
+}
+
+// MARK: - Helpers
+
+/// Creates an in-memory database with test data for destructive operation tests.
+/// Users 1 and 2 have orders; user 3 has no orders (safe to delete).
+private func makeTestDatabase() throws -> DatabaseQueue {
+    let db = try DatabaseQueue(path: ":memory:")
+    try db.write { db in
+        // Disable FK enforcement for test flexibility, then re-enable
+        try db.execute(sql: "PRAGMA foreign_keys = OFF")
+        try db.execute(sql: """
+            CREATE TABLE users (
+                id INTEGER PRIMARY KEY,
+                name TEXT NOT NULL,
+                email TEXT NOT NULL
+            )
+            """)
+        try db.execute(sql: """
+            INSERT INTO users (name, email) VALUES
+            ('Alice', 'alice@example.com'),
+            ('Bob', 'bob@example.com'),
+            ('Charlie', 'charlie@example.com')
+            """)
+        try db.execute(sql: """
+            CREATE TABLE orders (
+                id INTEGER PRIMARY KEY,
+                user_id INTEGER NOT NULL,
+                amount REAL NOT NULL
+            )
+            """)
+        try db.execute(sql: """
+            INSERT INTO orders (user_id, amount) VALUES
+            (1, 99.99),
+            (2, 150.00),
+            (3, 25.50)
+            """)
+    }
+    return db
+}
+
+/// A sequential mock model for tests. Returns responses in order.
+private struct TestSequentialModel: LanguageModel {
+    typealias UnavailableReason = Never
+
+    let responses: [String]
+    private let callCounter = CallCounter()
+
+    private final class CallCounter: @unchecked Sendable {
+        var count = 0
+        let lock = NSLock()
+
+        func next() -> Int {
+            lock.lock()
+            defer { lock.unlock() }
+            let c = count
+            count += 1
+            return c
+        }
+    }
+
+    init(responses: [String]) {
+        self.responses = responses
+    }
+
+    func respond<Content>(
+        within session: LanguageModelSession,
+        to prompt: Prompt,
+        generating type: Content.Type,
+        includeSchemaInPrompt: Bool,
+        options: GenerationOptions
+    ) async throws -> LanguageModelSession.Response<Content> where Content: Generable {
+        let idx = callCounter.next()
+        let text = idx < responses.count ? responses[idx] : "fallback response"
+        let rawContent = GeneratedContent(kind: .string(text))
+        let content = try Content(rawContent)
+        return LanguageModelSession.Response(
+            content: content,
+            rawContent: rawContent,
+            transcriptEntries: [][...]
+        )
+    }
+
+    func streamResponse<Content>(
+        within session: LanguageModelSession,
+        to prompt: Prompt,
+        generating type: Content.Type,
+        includeSchemaInPrompt: Bool,
+        options: GenerationOptions
+    ) -> sending LanguageModelSession.ResponseStream<Content> where Content: Generable {
+        let idx = callCounter.next()
+        let text = idx < responses.count ? responses[idx] : "fallback response"
+        let rawContent = GeneratedContent(kind: .string(text))
+        let content = try! Content(rawContent)
+        return LanguageModelSession.ResponseStream(content: content, rawContent: rawContent)
+    }
+}
+
+// MARK: - Tests: Destructive Operations Blocked Without Confirmation
+
+@Suite("Destructive Operations - Blocked Without Confirmation")
+struct DestructiveOperationsBlockedTests {
+
+    @Test("DELETE is blocked when no delegate is provided")
+    func deleteBlockedWithoutDelegate() async throws {
+        let db = try makeTestDatabase()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 1"
+        ])
+
+        // Unrestricted allowlist permits DELETE, but no delegate to confirm
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted
+        )
+
+        do {
+            _ = try await engine.send("Delete user 1")
+            Issue.record("Expected confirmationRequired error but send succeeded")
+        } catch let error as SwiftDBAIError {
+            guard case .confirmationRequired(let sql, let operation) = error else {
+                Issue.record("Expected confirmationRequired, got: \(error)")
+                return
+            }
+            #expect(sql.uppercased().contains("DELETE"))
+            #expect(operation == "delete")
+        }
+
+        // Verify the user was NOT deleted (data remains intact)
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 1")
+        }
+        #expect(count == 1, "User should NOT have been deleted")
+    }
+
+    @Test("DELETE is blocked when delegate rejects")
+    func deleteBlockedWhenDelegateRejects() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 2"
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted,
+            delegate: delegate
+        )
+
+        do {
+            _ = try await engine.send("Delete user 2")
+            Issue.record("Expected confirmationRequired error but send succeeded")
+        } catch let error as SwiftDBAIError {
+            guard case .confirmationRequired(let sql, let operation) = error else {
+                Issue.record("Expected confirmationRequired, got: \(error)")
+                return
+            }
+            #expect(sql.uppercased().contains("DELETE"))
+            #expect(operation == "delete")
+        }
+
+        // Verify delegate was consulted
+        #expect(delegate.confirmCalls.count == 1)
+        #expect(delegate.confirmCalls[0].statementKind == .delete)
+        #expect(delegate.confirmCalls[0].sql.uppercased().contains("DELETE"))
+
+        // Verify the data was NOT modified
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 2")
+        }
+        #expect(count == 1, "User should NOT have been deleted")
+
+        // Verify no SQL was actually executed (no willExecute/didExecute calls)
+        #expect(delegate.willExecuteCalls.isEmpty, "No SQL should have been executed")
+        #expect(delegate.didExecuteCalls.isEmpty, "No SQL should have been executed")
+    }
+
+    @Test("DELETE is blocked with MutationPolicy and no delegate")
+    func deleteBlockedWithMutationPolicyNoDelegate() async throws {
+        let db = try makeTestDatabase()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 3"
+        ])
+
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            requiresDestructiveConfirmation: true
+        )
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            mutationPolicy: policy
+        )
+
+        do {
+            _ = try await engine.send("Delete user 3")
+            Issue.record("Expected confirmationRequired error but send succeeded")
+        } catch let error as SwiftDBAIError {
+            guard case .confirmationRequired(let sql, let operation) = error else {
+                Issue.record("Expected confirmationRequired, got: \(error)")
+                return
+            }
+            #expect(sql.uppercased().contains("DELETE"))
+            #expect(operation == "delete")
+        }
+
+        // Data intact
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 3")
+        }
+        #expect(count == 1, "User should NOT have been deleted")
+    }
+
+    @Test("DELETE is blocked with MutationPolicy and rejecting delegate")
+    func deleteBlockedWithMutationPolicyRejectingDelegate() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM orders WHERE user_id = 1"
+        ])
+
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            requiresDestructiveConfirmation: true
+        )
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            mutationPolicy: policy,
+            delegate: delegate
+        )
+
+        do {
+            _ = try await engine.send("Delete all orders for user 1")
+            Issue.record("Expected confirmationRequired error but send succeeded")
+        } catch let error as SwiftDBAIError {
+            guard case .confirmationRequired = error else {
+                Issue.record("Expected confirmationRequired, got: \(error)")
+                return
+            }
+        }
+
+        // Delegate was consulted and rejected
+        #expect(delegate.confirmCalls.count == 1)
+        #expect(delegate.confirmCalls[0].statementKind == .delete)
+
+        // Orders remain
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM orders WHERE user_id = 1")
+        }
+        #expect(count == 1, "Orders should NOT have been deleted")
+    }
+
+    @Test("Default delegate implementation rejects destructive operations")
+    func defaultDelegateRejectsDestructive() async {
+        struct DefaultDelegate: SwiftDBAI.ToolExecutionDelegate {}
+        let delegate = DefaultDelegate()
+
+        let context = DestructiveOperationContext(
+            sql: "DELETE FROM users WHERE id = 1",
+            statementKind: .delete,
+            classification: .destructive(.delete),
+            description: "Delete from users"
+        )
+
+        let approved = await delegate.confirmDestructiveOperation(context)
+        #expect(approved == false, "Default delegate should reject destructive operations")
+    }
+
+    @Test("DELETE not in readOnly allowlist is rejected before delegate is consulted")
+    func deleteNotInAllowlistRejectedEarly() async throws {
+        let db = try makeTestDatabase()
+        let delegate = ApprovingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 1"
+        ])
+
+        // Read-only allowlist does NOT include DELETE
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .readOnly,
+            delegate: delegate
+        )
+
+        do {
+            _ = try await engine.send("Delete user 1")
+            Issue.record("Expected operationNotAllowed error")
+        } catch let error as SwiftDBAIError {
+            guard case .operationNotAllowed(let operation) = error else {
+                Issue.record("Expected operationNotAllowed, got: \(error)")
+                return
+            }
+            #expect(operation == "delete")
+        }
+
+        // Delegate should NOT have been consulted — the allowlist rejects before delegation
+        #expect(delegate.confirmCalls.isEmpty, "Delegate should not be consulted when op is not in allowlist")
+    }
+}
+
+// MARK: - Tests: Destructive Operations Allowed When Delegate Approves
+
+@Suite("Destructive Operations - Allowed When Delegate Approves")
+struct DestructiveOperationsAllowedTests {
+
+    @Test("DELETE succeeds when delegate approves")
+    func deleteSucceedsWithApprovingDelegate() async throws {
+        let db = try makeTestDatabase()
+        let delegate = ApprovingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 1",
+            "Successfully deleted 1 user."
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted,
+            delegate: delegate
+        )
+
+        let response = try await engine.send("Delete user 1")
+
+        // Delegate was consulted and approved
+        #expect(delegate.confirmCalls.count == 1)
+        #expect(delegate.confirmCalls[0].statementKind == .delete)
+        #expect(delegate.confirmCalls[0].sql.uppercased().contains("DELETE"))
+        #expect(delegate.confirmCalls[0].targetTable == "users")
+
+        // SQL was executed
+        #expect(delegate.willExecuteCalls.count == 1)
+        #expect(delegate.didExecuteCalls.count == 1)
+        #expect(delegate.didExecuteCalls[0].success == true)
+
+        // Verify the data was actually deleted
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 1")
+        }
+        #expect(count == 0, "User should have been deleted")
+
+        // Response should contain meaningful content
+        #expect(response.sql?.uppercased().contains("DELETE") == true)
+        #expect(response.queryResult != nil)
+    }
+
+    @Test("DELETE with MutationPolicy succeeds when delegate approves")
+    func deleteWithPolicySucceedsWhenApproved() async throws {
+        let db = try makeTestDatabase()
+        let delegate = ApprovingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM orders WHERE user_id = 2",
+            "Deleted 1 order."
+        ])
+
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            requiresDestructiveConfirmation: true
+        )
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            mutationPolicy: policy,
+            delegate: delegate
+        )
+
+        let response = try await engine.send("Delete all orders for user 2")
+
+        // Delegate approved
+        #expect(delegate.confirmCalls.count == 1)
+
+        // Data was actually deleted
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM orders WHERE user_id = 2")
+        }
+        #expect(count == 0, "Orders should have been deleted")
+        #expect(response.sql?.uppercased().contains("DELETE") == true)
+    }
+
+    @Test("AutoApproveDelegate allows DELETE without user interaction")
+    func autoApproveDelegateAllowsDelete() async throws {
+        let db = try makeTestDatabase()
+        let delegate = AutoApproveDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 3",
+            "Deleted 1 user."
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted,
+            delegate: delegate
+        )
+
+        let response = try await engine.send("Delete user 3")
+
+        // Should succeed without error
+        #expect(response.sql?.uppercased().contains("DELETE") == true)
+
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 3")
+        }
+        #expect(count == 0, "User should have been deleted")
+    }
+
+    @Test("sendConfirmed bypasses delegate and executes directly")
+    func sendConfirmedBypassesDelegate() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "Deleted 1 user."
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted,
+            delegate: delegate
+        )
+
+        // sendConfirmed should execute directly without consulting the delegate for confirmation
+        let response = try await engine.sendConfirmed(
+            "Delete user 1",
+            confirmedSQL: "DELETE FROM users WHERE id = 1"
+        )
+
+        // Delegate was NOT asked to confirm (sendConfirmed skips confirmation)
+        #expect(delegate.confirmCalls.isEmpty)
+
+        // But willExecute/didExecute hooks were still called
+        #expect(delegate.willExecuteCalls.count == 1)
+        #expect(delegate.didExecuteCalls.count == 1)
+        #expect(delegate.didExecuteCalls[0].success == true)
+
+        // Data was deleted
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 1")
+        }
+        #expect(count == 0)
+        #expect(response.summary.contains("deleted") || response.summary.contains("Deleted") || response.summary.contains("1"))
+    }
+}
+
+// MARK: - Tests: Delegate Context Correctness
+
+@Suite("Destructive Operations - Delegate Context")
+struct DestructiveOperationContextTests {
+
+    @Test("Delegate receives correct context for DELETE on specific table")
+    func delegateReceivesCorrectContext() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM orders WHERE amount < 50"
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted,
+            delegate: delegate
+        )
+
+        do {
+            _ = try await engine.send("Delete cheap orders")
+            Issue.record("Expected confirmationRequired error")
+        } catch is SwiftDBAIError {
+            // Expected
+        }
+
+        #expect(delegate.confirmCalls.count == 1)
+        let ctx = delegate.confirmCalls[0]
+        #expect(ctx.statementKind == .delete)
+        #expect(ctx.classification == .destructive(.delete))
+        #expect(ctx.classification.requiresConfirmation == true)
+        #expect(ctx.sql.uppercased().contains("DELETE FROM ORDERS"))
+        #expect(ctx.targetTable == "orders")
+        #expect(!ctx.description.isEmpty)
+    }
+
+    @Test("Non-destructive operations do not consult delegate")
+    func selectDoesNotConsultDelegate() async throws {
+        let db = try makeTestDatabase()
+        let delegate = ApprovingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "SELECT COUNT(*) FROM users",
+            "There are 3 users."
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .unrestricted,
+            delegate: delegate
+        )
+
+        _ = try await engine.send("How many users?")
+
+        // Delegate should NOT have been asked to confirm (SELECT is not destructive)
+        #expect(delegate.confirmCalls.isEmpty)
+
+        // But willExecute/didExecute should still be called (observation hooks)
+        #expect(delegate.willExecuteCalls.count == 1)
+        #expect(delegate.didExecuteCalls.count == 1)
+    }
+
+    @Test("INSERT does not require confirmation even with delegate")
+    func insertDoesNotRequireConfirmation() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "INSERT INTO users (name, email) VALUES ('Dave', 'dave@example.com')",
+            "Inserted 1 row."
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .standard,
+            delegate: delegate
+        )
+
+        let response = try await engine.send("Add user Dave")
+
+        // No confirmation needed for INSERT
+        #expect(delegate.confirmCalls.isEmpty)
+        #expect(response.sql?.uppercased().contains("INSERT") == true)
+
+        // Verify the insert happened
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE name = 'Dave'")
+        }
+        #expect(count == 1)
+    }
+
+    @Test("UPDATE does not require confirmation even with delegate")
+    func updateDoesNotRequireConfirmation() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "UPDATE users SET email = 'alice-new@example.com' WHERE id = 1",
+            "Updated 1 row."
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            allowlist: .standard,
+            delegate: delegate
+        )
+
+        let response = try await engine.send("Update Alice's email")
+
+        // No confirmation needed for UPDATE
+        #expect(delegate.confirmCalls.isEmpty)
+        #expect(response.sql?.uppercased().contains("UPDATE") == true)
+    }
+}
+
+// MARK: - Tests: MutationPolicy Confirmation Flag
+
+@Suite("Destructive Operations - MutationPolicy Confirmation Control")
+struct MutationPolicyConfirmationTests {
+
+    @Test("DELETE skips confirmation when requiresDestructiveConfirmation is false")
+    func deleteSkipsConfirmationWhenDisabled() async throws {
+        let db = try makeTestDatabase()
+        let delegate = RejectingTrackingDelegate()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 1",
+            "Deleted 1 user."
+        ])
+
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            requiresDestructiveConfirmation: false  // Explicitly disabled
+        )
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            mutationPolicy: policy,
+            delegate: delegate
+        )
+
+        // Should succeed without confirmation since the policy disables it
+        let response = try await engine.send("Delete user 1")
+
+        // Delegate should NOT have been consulted for confirmation
+        #expect(delegate.confirmCalls.isEmpty)
+
+        // But the SQL should have executed
+        #expect(response.sql?.uppercased().contains("DELETE") == true)
+
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 1")
+        }
+        #expect(count == 0, "User should have been deleted without confirmation")
+    }
+
+    @Test("MutationPolicy.requiresConfirmation only triggers for DELETE")
+    func requiresConfirmationOnlyForDelete() {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            requiresDestructiveConfirmation: true
+        )
+
+        #expect(policy.requiresConfirmation(for: .delete) == true)
+        #expect(policy.requiresConfirmation(for: .select) == false)
+        #expect(policy.requiresConfirmation(for: .insert) == false)
+        #expect(policy.requiresConfirmation(for: .update) == false)
+    }
+
+    @Test("MutationPolicy.readOnly never requires confirmation (no delete allowed)")
+    func readOnlyNeverRequiresConfirmation() {
+        let policy = MutationPolicy.readOnly
+
+        #expect(policy.requiresConfirmation(for: .select) == false)
+        #expect(policy.requiresConfirmation(for: .delete) == true) // Would require confirmation IF allowed
+        #expect(policy.isOperationAllowed(.delete) == false)       // But it's not allowed at all
+    }
+
+    @Test("Table-restricted DELETE is blocked for disallowed tables")
+    func tableRestrictedDeleteBlocked() async throws {
+        let db = try makeTestDatabase()
+        let model = TestSequentialModel(responses: [
+            "DELETE FROM users WHERE id = 1"
+        ])
+
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            allowedTables: ["orders"],  // Only orders, NOT users
+            requiresDestructiveConfirmation: true
+        )
+
+        let engine = ChatEngine(
+            database: db,
+            model: model,
+            mutationPolicy: policy
+        )
+
+        do {
+            _ = try await engine.send("Delete user 1")
+            Issue.record("Expected tableNotAllowedForMutation error")
+        } catch let error as SwiftDBAIError {
+            guard case .tableNotAllowedForMutation(let tableName, let operation) = error else {
+                Issue.record("Expected tableNotAllowedForMutation, got: \(error)")
+                return
+            }
+            #expect(tableName == "users")
+            #expect(operation == "delete")
+        }
+
+        // User was not deleted
+        let count = try await db.read { db in
+            try Int.fetchOne(db, sql: "SELECT COUNT(*) FROM users WHERE id = 1")
+        }
+        #expect(count == 1)
+    }
+}

Tests/SwiftDBAITests/Helpers/MockLanguageModel.swift

@@ -0,0 +1,49 @@
+// MockLanguageModel.swift
+// SwiftDBAI Tests
+//
+// A mock LanguageModel for unit tests that returns canned responses.
+
+import AnyLanguageModel
+import Foundation
+
+/// A mock language model that returns a configurable canned response.
+///
+/// Used in tests to avoid hitting a real LLM provider.
+struct MockLanguageModel: LanguageModel {
+    typealias UnavailableReason = Never
+
+    /// The text the mock will return from `respond(...)`.
+    let responseText: String
+
+    init(responseText: String = "Mock summary response.") {
+        self.responseText = responseText
+    }
+
+    func respond<Content>(
+        within session: LanguageModelSession,
+        to prompt: Prompt,
+        generating type: Content.Type,
+        includeSchemaInPrompt: Bool,
+        options: GenerationOptions
+    ) async throws -> LanguageModelSession.Response<Content> where Content: Generable {
+        let rawContent = GeneratedContent(kind: .string(responseText))
+        let content = try Content(rawContent)
+        return LanguageModelSession.Response(
+            content: content,
+            rawContent: rawContent,
+            transcriptEntries: [][...]
+        )
+    }
+
+    func streamResponse<Content>(
+        within session: LanguageModelSession,
+        to prompt: Prompt,
+        generating type: Content.Type,
+        includeSchemaInPrompt: Bool,
+        options: GenerationOptions
+    ) -> sending LanguageModelSession.ResponseStream<Content> where Content: Generable {
+        let rawContent = GeneratedContent(kind: .string(responseText))
+        let content = try! Content(rawContent)
+        return LanguageModelSession.ResponseStream(content: content, rawContent: rawContent)
+    }
+}

Tests/SwiftDBAITests/LocalProviderConfigurationTests.swift

@@ -0,0 +1,337 @@
+// LocalProviderConfigurationTests.swift
+// SwiftDBAI Tests
+//
+// Tests for local/self-hosted provider configurations (Ollama, llama.cpp):
+// factory methods, endpoint discovery, connection handling, and model creation.
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+@testable import SwiftDBAI
+import Testing
+
+@Suite("Local Provider Configuration")
+struct LocalProviderConfigurationTests {
+
+    // MARK: - Ollama Configuration
+
+    @Test("Ollama configuration stores provider and model")
+    func ollamaBasicConfiguration() {
+        let config = ProviderConfiguration.ollama(model: "llama3.2")
+
+        #expect(config.provider == .ollama)
+        #expect(config.model == "llama3.2")
+        #expect(config.baseURL == OllamaLanguageModel.defaultBaseURL)
+    }
+
+    @Test("Ollama configuration produces OllamaLanguageModel")
+    func ollamaMakeModel() {
+        let config = ProviderConfiguration.ollama(model: "qwen2.5")
+
+        let model = config.makeModel()
+        #expect(model is OllamaLanguageModel)
+    }
+
+    @Test("Ollama with custom base URL for remote instance")
+    func ollamaCustomBaseURL() {
+        let remoteURL = URL(string: "http://192.168.1.100:11434")!
+        let config = ProviderConfiguration.ollama(
+            model: "mistral",
+            baseURL: remoteURL
+        )
+
+        #expect(config.baseURL == remoteURL)
+        #expect(config.provider == .ollama)
+        let model = config.makeModel()
+        #expect(model is OllamaLanguageModel)
+    }
+
+    @Test("Ollama does not require an API key")
+    func ollamaNoAPIKey() {
+        let config = ProviderConfiguration.ollama(model: "llama3.2")
+
+        // Ollama doesn't need an API key, so the key is empty
+        #expect(config.apiKey == "")
+        // hasValidAPIKey returns false because key is empty, but that's expected
+        // for local providers — they don't need authentication
+        #expect(!config.hasValidAPIKey)
+    }
+
+    @Test("Ollama model is available without API key")
+    func ollamaModelAvailable() {
+        let config = ProviderConfiguration.ollama(model: "llama3.2")
+        let model = config.makeModel()
+        #expect(model.isAvailable)
+    }
+
+    // MARK: - llama.cpp Configuration
+
+    @Test("llama.cpp configuration stores provider and model")
+    func llamaCppBasicConfiguration() {
+        let config = ProviderConfiguration.llamaCpp(model: "my-model")
+
+        #expect(config.provider == .llamaCpp)
+        #expect(config.model == "my-model")
+        #expect(config.baseURL == LocalProviderDiscovery.defaultLlamaCppURL)
+    }
+
+    @Test("llama.cpp uses 'default' model name by default")
+    func llamaCppDefaultModel() {
+        let config = ProviderConfiguration.llamaCpp()
+
+        #expect(config.model == "default")
+    }
+
+    @Test("llama.cpp configuration produces OpenAILanguageModel (compatible API)")
+    func llamaCppMakeModel() {
+        let config = ProviderConfiguration.llamaCpp(model: "my-gguf")
+
+        let model = config.makeModel()
+        // llama.cpp uses OpenAI-compatible API
+        #expect(model is OpenAILanguageModel)
+    }
+
+    @Test("llama.cpp with custom base URL")
+    func llamaCppCustomBaseURL() {
+        let customURL = URL(string: "http://localhost:9090")!
+        let config = ProviderConfiguration.llamaCpp(
+            model: "custom-model",
+            baseURL: customURL
+        )
+
+        #expect(config.baseURL == customURL)
+        let model = config.makeModel()
+        #expect(model is OpenAILanguageModel)
+    }
+
+    @Test("llama.cpp with API key authentication")
+    func llamaCppWithAPIKey() {
+        let config = ProviderConfiguration.llamaCpp(
+            model: "secured-model",
+            apiKey: "my-secret-key"
+        )
+
+        #expect(config.apiKey == "my-secret-key")
+        #expect(config.hasValidAPIKey)
+    }
+
+    @Test("llama.cpp without API key")
+    func llamaCppNoAPIKey() {
+        let config = ProviderConfiguration.llamaCpp(model: "open-model")
+
+        #expect(config.apiKey == "")
+    }
+
+    // MARK: - Provider Enum
+
+    @Test("Provider enum includes ollama and llamaCpp cases")
+    func providerEnumHasLocalCases() {
+        let cases = ProviderConfiguration.Provider.allCases
+        #expect(cases.contains(.ollama))
+        #expect(cases.contains(.llamaCpp))
+        // Total: openAI, anthropic, gemini, openAICompatible, ollama, llamaCpp
+        #expect(cases.count == 6)
+    }
+
+    // MARK: - fromEnvironment
+
+    @Test("fromEnvironment creates Ollama configuration")
+    func fromEnvironmentOllama() {
+        let config = ProviderConfiguration.fromEnvironment(
+            provider: .ollama,
+            environmentVariable: "NONEXISTENT_OLLAMA_KEY",
+            model: "llama3.2"
+        )
+
+        #expect(config.provider == .ollama)
+        #expect(config.model == "llama3.2")
+    }
+
+    @Test("fromEnvironment creates llama.cpp configuration")
+    func fromEnvironmentLlamaCpp() {
+        let config = ProviderConfiguration.fromEnvironment(
+            provider: .llamaCpp,
+            environmentVariable: "NONEXISTENT_LLAMACPP_KEY",
+            model: "default"
+        )
+
+        #expect(config.provider == .llamaCpp)
+        #expect(config.model == "default")
+    }
+
+    // MARK: - ChatEngine Convenience Init with Local Providers
+
+    @Test("ChatEngine can be created with Ollama provider")
+    func chatEngineWithOllama() throws {
+        let dbQueue = try GRDB.DatabaseQueue()
+        let config = ProviderConfiguration.ollama(model: "llama3.2")
+        let engine = ChatEngine(database: dbQueue, provider: config)
+
+        #expect(engine.tableCount == nil) // schema not yet introspected
+    }
+
+    @Test("ChatEngine can be created with llama.cpp provider")
+    func chatEngineWithLlamaCpp() throws {
+        let dbQueue = try GRDB.DatabaseQueue()
+        let config = ProviderConfiguration.llamaCpp()
+        let engine = ChatEngine(database: dbQueue, provider: config)
+
+        #expect(engine.tableCount == nil)
+    }
+
+    // MARK: - LocalProviderType
+
+    @Test("LocalProviderType has expected raw values")
+    func localProviderTypeRawValues() {
+        #expect(LocalProviderType.ollama.rawValue == "ollama")
+        #expect(LocalProviderType.llamaCpp.rawValue == "llama.cpp")
+    }
+
+    @Test("LocalProviderType CaseIterable includes both cases")
+    func localProviderTypeCases() {
+        let cases = LocalProviderType.allCases
+        #expect(cases.count == 2)
+        #expect(cases.contains(.ollama))
+        #expect(cases.contains(.llamaCpp))
+    }
+
+    // MARK: - LocalProviderEndpoint
+
+    @Test("LocalProviderEndpoint description includes status and model count")
+    func endpointDescription() {
+        let endpoint = LocalProviderEndpoint(
+            baseURL: URL(string: "http://localhost:11434")!,
+            providerType: .ollama,
+            isReachable: true,
+            availableModels: ["llama3.2", "qwen2.5"]
+        )
+
+        #expect(endpoint.description.contains("ollama"))
+        #expect(endpoint.description.contains("reachable"))
+        #expect(endpoint.description.contains("2 models"))
+    }
+
+    @Test("LocalProviderEndpoint shows unreachable when not connected")
+    func endpointUnreachableDescription() {
+        let endpoint = LocalProviderEndpoint(
+            baseURL: URL(string: "http://localhost:8080")!,
+            providerType: .llamaCpp,
+            isReachable: false,
+            availableModels: []
+        )
+
+        #expect(endpoint.description.contains("unreachable"))
+        #expect(endpoint.description.contains("0 models"))
+    }
+
+    @Test("LocalProviderEndpoint equality works correctly")
+    func endpointEquality() {
+        let a = LocalProviderEndpoint(
+            baseURL: URL(string: "http://localhost:11434")!,
+            providerType: .ollama,
+            isReachable: true,
+            availableModels: ["llama3.2"]
+        )
+        let b = LocalProviderEndpoint(
+            baseURL: URL(string: "http://localhost:11434")!,
+            providerType: .ollama,
+            isReachable: true,
+            availableModels: ["llama3.2"]
+        )
+        let c = LocalProviderEndpoint(
+            baseURL: URL(string: "http://localhost:11434")!,
+            providerType: .ollama,
+            isReachable: false,
+            availableModels: []
+        )
+
+        #expect(a == b)
+        #expect(a != c)
+    }
+
+    // MARK: - Discovery (No Local Server Running)
+
+    @Test("Discovery returns unreachable when no server is running")
+    func discoveryUnreachableEndpoint() async {
+        // Use a port that's almost certainly not running anything
+        let endpoint = await LocalProviderDiscovery.discover(
+            providerType: .ollama,
+            host: "127.0.0.1",
+            port: 59999,
+            timeout: 1
+        )
+
+        #expect(!endpoint.isReachable)
+        #expect(endpoint.availableModels.isEmpty)
+        #expect(endpoint.providerType == .ollama)
+    }
+
+    @Test("isOllamaRunning returns false for unreachable endpoint")
+    func ollamaNotRunning() async {
+        let unreachableURL = URL(string: "http://127.0.0.1:59998")!
+        let running = await LocalProviderDiscovery.isOllamaRunning(
+            at: unreachableURL,
+            timeout: 1
+        )
+
+        #expect(!running)
+    }
+
+    @Test("isLlamaCppRunning returns false for unreachable endpoint")
+    func llamaCppNotRunning() async {
+        let unreachableURL = URL(string: "http://127.0.0.1:59997")!
+        let running = await LocalProviderDiscovery.isLlamaCppRunning(
+            at: unreachableURL,
+            timeout: 1
+        )
+
+        #expect(!running)
+    }
+
+    @Test("listOllamaModels returns empty for unreachable endpoint")
+    func ollamaModelsUnreachable() async {
+        let unreachableURL = URL(string: "http://127.0.0.1:59996")!
+        let models = await LocalProviderDiscovery.listOllamaModels(
+            at: unreachableURL,
+            timeout: 1
+        )
+
+        #expect(models.isEmpty)
+    }
+
+    @Test("listLlamaCppModels returns empty for unreachable endpoint")
+    func llamaCppModelsUnreachable() async {
+        let unreachableURL = URL(string: "http://127.0.0.1:59995")!
+        let models = await LocalProviderDiscovery.listLlamaCppModels(
+            at: unreachableURL,
+            timeout: 1
+        )
+
+        #expect(models.isEmpty)
+    }
+
+    @Test("discoverAll returns endpoints for both provider types")
+    func discoverAllReturnsAllProviders() async {
+        // Use very short timeout since we likely don't have servers running
+        let endpoints = await LocalProviderDiscovery.discoverAll(timeout: 0.5)
+
+        // Should return exactly 2 endpoints (one per well-known provider)
+        #expect(endpoints.count == 2)
+
+        let types = Set(endpoints.map(\.providerType))
+        #expect(types.contains(.ollama))
+        #expect(types.contains(.llamaCpp))
+    }
+
+    // MARK: - Default URLs
+
+    @Test("Default Ollama URL is correct")
+    func defaultOllamaURL() {
+        #expect(LocalProviderDiscovery.defaultOllamaURL.absoluteString == "http://localhost:11434")
+    }
+
+    @Test("Default llama.cpp URL is correct")
+    func defaultLlamaCppURL() {
+        #expect(LocalProviderDiscovery.defaultLlamaCppURL.absoluteString == "http://localhost:8080")
+    }
+}

Tests/SwiftDBAITests/MultiTurnContextTests.swift

@@ -0,0 +1,363 @@
+// MultiTurnContextTests.swift
+// SwiftDBAI Tests
+//
+// Tests verifying multi-turn conversation context — follow-up queries
+// correctly reference the prior query's table, columns, and results.
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+import Testing
+
+@testable import SwiftDBAI
+
+@Suite("Multi-Turn Context Tests")
+struct MultiTurnContextTests {
+
+    // MARK: - Test Database Setup
+
+    /// Creates an in-memory database with users (including age) and orders.
+    private func makeTestDatabase() throws -> DatabaseQueue {
+        let db = try DatabaseQueue(path: ":memory:")
+        try db.write { db in
+            try db.execute(sql: """
+                CREATE TABLE users (
+                    id INTEGER PRIMARY KEY,
+                    name TEXT NOT NULL,
+                    age INTEGER NOT NULL,
+                    email TEXT NOT NULL,
+                    city TEXT NOT NULL
+                )
+                """)
+            try db.execute(sql: """
+                INSERT INTO users (name, age, email, city) VALUES
+                ('Alice', 25, 'alice@example.com', 'New York'),
+                ('Bob', 35, 'bob@example.com', 'San Francisco'),
+                ('Charlie', 42, 'charlie@example.com', 'New York'),
+                ('Diana', 28, 'diana@example.com', 'Chicago'),
+                ('Eve', 55, 'eve@example.com', 'San Francisco')
+                """)
+            try db.execute(sql: """
+                CREATE TABLE orders (
+                    id INTEGER PRIMARY KEY,
+                    user_id INTEGER NOT NULL,
+                    amount REAL NOT NULL,
+                    status TEXT NOT NULL,
+                    created_at TEXT NOT NULL,
+                    FOREIGN KEY (user_id) REFERENCES users(id)
+                )
+                """)
+            try db.execute(sql: """
+                INSERT INTO orders (user_id, amount, status, created_at) VALUES
+                (1, 99.99, 'completed', '2024-01-15'),
+                (1, 49.50, 'pending', '2024-02-20'),
+                (2, 150.00, 'completed', '2024-01-10'),
+                (3, 200.00, 'completed', '2024-03-01'),
+                (4, 75.00, 'cancelled', '2024-02-05')
+                """)
+        }
+        return db
+    }
+
+    // MARK: - Multi-Turn Context Tests
+
+    @Test("Follow-up 'filter those by age > 30' references prior 'show all users' context")
+    func followUpFilterReferencesUsersTable() async throws {
+        let db = try makeTestDatabase()
+
+        // Turn 1: "show all users" → SELECT * FROM users (returns 5 rows, LLM summary needed)
+        // Turn 2: "filter those by age > 30" → should reference users table from context
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT * FROM users",
+            "Here are all 5 users in the database.",
+            "SELECT * FROM users WHERE age > 30",
+            "Found 3 users over 30: Bob (35), Charlie (42), and Eve (55)."
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        // First turn: show all users
+        let response1 = try await engine.send("show all users")
+        #expect(response1.sql == "SELECT * FROM users")
+        #expect(response1.queryResult?.rowCount == 5)
+
+        // Second turn: follow-up with implicit reference
+        let response2 = try await engine.send("filter those by age > 30")
+        #expect(response2.sql == "SELECT * FROM users WHERE age > 30")
+        #expect(response2.queryResult?.rowCount == 3)
+
+        // Verify the follow-up prompt includes conversation history
+        let prompts = mock.capturedPrompts
+        // Find the prompt for the second SQL generation (skip summary prompts)
+        let followUpSQLPrompt = prompts.first { prompt in
+            prompt.contains("filter those by age > 30") && prompt.contains("CONVERSATION HISTORY")
+        }
+        #expect(followUpSQLPrompt != nil, "Follow-up prompt should contain CONVERSATION HISTORY")
+
+        // The conversation history should include the prior query and its SQL
+        if let prompt = followUpSQLPrompt {
+            #expect(prompt.contains("show all users"), "History should contain prior user message")
+            #expect(prompt.contains("SELECT * FROM users"), "History should contain prior SQL")
+            #expect(prompt.contains("filter those by age > 30"), "Prompt should contain current question")
+        }
+    }
+
+    @Test("Follow-up correctly inherits table context across multiple turns")
+    func multipleFollowUpsInheritContext() async throws {
+        let db = try makeTestDatabase()
+
+        // 3-turn conversation narrowing down results
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT * FROM users",
+            "Here are all 5 users.",
+            "SELECT * FROM users WHERE city = 'New York'",
+            "Found 2 users in New York: Alice and Charlie.",
+            "SELECT * FROM users WHERE city = 'New York' AND age > 30",
+            "Charlie (42) is the only New York user over 30."
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        // Turn 1
+        _ = try await engine.send("show all users")
+
+        // Turn 2 — narrows by city
+        let response2 = try await engine.send("only those in New York")
+        #expect(response2.sql == "SELECT * FROM users WHERE city = 'New York'")
+        #expect(response2.queryResult?.rowCount == 2)
+
+        // Turn 3 — further narrows by age
+        let response3 = try await engine.send("now filter by age over 30")
+        #expect(response3.sql == "SELECT * FROM users WHERE city = 'New York' AND age > 30")
+        #expect(response3.queryResult?.rowCount == 1)
+
+        // Verify third turn's prompt includes the full conversation history
+        let prompts = mock.capturedPrompts
+        let thirdTurnPrompt = prompts.last { prompt in
+            prompt.contains("now filter by age over 30") && prompt.contains("CONVERSATION HISTORY")
+        }
+        #expect(thirdTurnPrompt != nil)
+
+        if let prompt = thirdTurnPrompt {
+            // Should include both prior user messages
+            #expect(prompt.contains("show all users"))
+            #expect(prompt.contains("only those in New York"))
+            // Should include prior SQL
+            #expect(prompt.contains("SELECT * FROM users"))
+            #expect(prompt.contains("SELECT * FROM users WHERE city = 'New York'"))
+        }
+    }
+
+    @Test("Follow-up switching tables preserves cross-table context")
+    func followUpSwitchesTableWithContext() async throws {
+        let db = try makeTestDatabase()
+
+        // Turn 1: query users, Turn 2: ask about their orders
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT name, age FROM users WHERE age > 30",
+            "Found 3 users over 30.",
+            "SELECT o.id, u.name, o.amount, o.status FROM orders o JOIN users u ON o.user_id = u.id WHERE u.age > 30",
+            "Bob has a $150 completed order, Charlie has a $200 completed order."
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        // Turn 1: users over 30
+        let response1 = try await engine.send("show users over 30")
+        #expect(response1.queryResult?.rowCount == 3)
+
+        // Turn 2: their orders — references the previous result context
+        let response2 = try await engine.send("show their orders")
+        #expect(response2.sql?.contains("JOIN") == true)
+
+        // Verify the follow-up prompt contains the users context
+        let prompts = mock.capturedPrompts
+        let orderPrompt = prompts.first { prompt in
+            prompt.contains("show their orders") && prompt.contains("CONVERSATION HISTORY")
+        }
+        #expect(orderPrompt != nil)
+
+        if let prompt = orderPrompt {
+            #expect(prompt.contains("show users over 30"), "Should contain prior user message")
+            #expect(prompt.contains("age > 30"), "Should contain prior SQL context for table reference")
+        }
+    }
+
+    @Test("Conversation history includes SQL from prior turns for context")
+    func historyIncludesSQLFromPriorTurns() async throws {
+        let db = try makeTestDatabase()
+
+        // Both queries are aggregates → no LLM summarization needed
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT COUNT(*) FROM users",
+            "SELECT COUNT(*) FROM users WHERE age > 30",
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        // Turn 1
+        let r1 = try await engine.send("how many users are there?")
+        #expect(r1.sql == "SELECT COUNT(*) FROM users")
+
+        // Turn 2 — references "those" implicitly
+        let r2 = try await engine.send("how many of those are over 30?")
+        #expect(r2.sql == "SELECT COUNT(*) FROM users WHERE age > 30")
+
+        // Verify engine history has all 4 messages (2 user + 2 assistant)
+        let messages = engine.messages
+        #expect(messages.count == 4)
+        #expect(messages[0].role == .user)
+        #expect(messages[0].content == "how many users are there?")
+        #expect(messages[1].role == .assistant)
+        #expect(messages[1].sql == "SELECT COUNT(*) FROM users")
+        #expect(messages[2].role == .user)
+        #expect(messages[2].content == "how many of those are over 30?")
+        #expect(messages[3].role == .assistant)
+        #expect(messages[3].sql == "SELECT COUNT(*) FROM users WHERE age > 30")
+
+        // The second prompt should reference the first query SQL
+        let prompts = mock.capturedPrompts
+        #expect(prompts.count >= 2)
+        let secondPrompt = prompts[1]
+        #expect(secondPrompt.contains("CONVERSATION HISTORY"))
+        #expect(secondPrompt.contains("SELECT COUNT(*) FROM users"))
+        #expect(secondPrompt.contains("how many users are there?"))
+    }
+
+    @Test("Follow-up after aggregate uses prior table context")
+    func followUpAfterAggregateUsesTableContext() async throws {
+        let db = try makeTestDatabase()
+
+        // Turn 1: aggregate (no LLM summary needed)
+        // Turn 2: follow-up referencing "those"
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT AVG(age) FROM users",
+            "SELECT name, age FROM users WHERE age > 35",
+            "Charlie (42) and Eve (55) are older than average."
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        // Turn 1: average age → aggregate, template summary
+        let r1 = try await engine.send("what is the average age of users?")
+        #expect(r1.sql == "SELECT AVG(age) FROM users")
+
+        // Turn 2: "who is above that?" — needs the avg context
+        let r2 = try await engine.send("who is above average?")
+        #expect(r2.queryResult?.rowCount == 2)
+
+        // Verify context passed
+        let prompts = mock.capturedPrompts
+        let followUp = prompts.first { prompt in
+            prompt.contains("who is above average?") && prompt.contains("CONVERSATION HISTORY")
+        }
+        #expect(followUp != nil)
+        if let prompt = followUp {
+            #expect(prompt.contains("AVG(age)"), "Should include prior aggregate SQL for context")
+            #expect(prompt.contains("users"), "Should include table reference from prior turn")
+        }
+    }
+
+    @Test("Context window limits how much history is visible in follow-ups")
+    func contextWindowLimitsHistoryInFollowUps() async throws {
+        let db = try makeTestDatabase()
+
+        // 3 turns, but context window of 2 messages
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT COUNT(*) FROM users",
+            "SELECT COUNT(*) FROM orders",
+            "SELECT COUNT(*) FROM users WHERE age > 30",
+        ])
+
+        let config = ChatEngineConfiguration(
+            queryTimeout: nil,
+            contextWindowSize: 2
+        )
+
+        let engine = ChatEngine(
+            database: db,
+            model: mock,
+            configuration: config
+        )
+
+        _ = try await engine.send("how many users?")
+        _ = try await engine.send("how many orders?")
+        _ = try await engine.send("how many users over 30?")
+
+        // The third prompt should only have the last 2 messages from turn 2
+        let prompts = mock.capturedPrompts
+        #expect(prompts.count >= 3)
+
+        let thirdPrompt = prompts[2]
+        #expect(thirdPrompt.contains("CONVERSATION HISTORY"))
+        // Turn 2 context should be present
+        #expect(thirdPrompt.contains("how many orders?"))
+        #expect(thirdPrompt.contains("SELECT COUNT(*) FROM orders"))
+        // Turn 1 context should be trimmed (window=2 means last 2 messages)
+        #expect(!thirdPrompt.contains("how many users?\n"), "First turn should be trimmed from context window")
+    }
+
+    @Test("clearHistory resets context so follow-ups have no prior history")
+    func clearHistoryResetsFollowUpContext() async throws {
+        let db = try makeTestDatabase()
+
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT * FROM users",
+            "Here are the 5 users.",
+            "SELECT COUNT(*) FROM users",
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        // Turn 1
+        _ = try await engine.send("show all users")
+        #expect(engine.messages.count == 2)
+
+        // Clear history
+        engine.clearHistory()
+        #expect(engine.messages.isEmpty)
+
+        // Turn 2 after clear — should NOT have conversation history
+        _ = try await engine.send("count all users")
+
+        let prompts = mock.capturedPrompts
+        let lastPrompt = prompts.last!
+        // After clearing, the prompt should NOT contain conversation history
+        #expect(!lastPrompt.contains("CONVERSATION HISTORY"),
+                "After clearHistory(), follow-up should not have prior context")
+        #expect(!lastPrompt.contains("show all users"),
+                "After clearHistory(), prior messages should be gone")
+    }
+
+    @Test("Multi-turn with result data in context enables informed follow-ups")
+    func resultDataInContextEnablesInformedFollowUps() async throws {
+        let db = try makeTestDatabase()
+
+        // Turn 1: list users → multi-row result, LLM summarizes
+        // Turn 2: "sort those by age" → references same table
+        let mock = PromptCapturingMockModel(responses: [
+            "SELECT name, age, city FROM users",
+            "Found 5 users: Alice (25, NY), Bob (35, SF), Charlie (42, NY), Diana (28, Chicago), Eve (55, SF).",
+            "SELECT name, age, city FROM users ORDER BY age DESC",
+            "Users sorted by age: Eve (55), Charlie (42), Bob (35), Diana (28), Alice (25)."
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        let r1 = try await engine.send("list all users with their age and city")
+        #expect(r1.queryResult?.rowCount == 5)
+        #expect(r1.queryResult?.columns.contains("age") == true)
+        #expect(r1.queryResult?.columns.contains("city") == true)
+
+        let r2 = try await engine.send("sort those by age descending")
+        #expect(r2.sql == "SELECT name, age, city FROM users ORDER BY age DESC")
+
+        // Verify the assistant message in history includes the SQL
+        let messages = engine.messages
+        #expect(messages.count == 4)
+        // First assistant message should have the SQL recorded
+        #expect(messages[1].sql == "SELECT name, age, city FROM users")
+        // Second assistant should have the sorted SQL
+        #expect(messages[3].sql == "SELECT name, age, city FROM users ORDER BY age DESC")
+    }
+}

Tests/SwiftDBAITests/OnDeviceProviderConfigurationTests.swift

@@ -0,0 +1,508 @@
+// OnDeviceProviderConfigurationTests.swift
+// SwiftDBAI Tests
+//
+// Tests for on-device provider configurations (CoreML, MLX) including
+// configuration validation, inference pipeline setup, and system readiness.
+
+import AnyLanguageModel
+import Foundation
+@testable import SwiftDBAI
+import Testing
+
+@Suite("OnDeviceProviderConfiguration")
+struct OnDeviceProviderConfigurationTests {
+
+    // MARK: - OnDeviceProviderType
+
+    @Test("OnDeviceProviderType has CoreML and MLX cases")
+    func providerTypeCases() {
+        let cases = OnDeviceProviderType.allCases
+        #expect(cases.count == 2)
+        #expect(cases.contains(.coreML))
+        #expect(cases.contains(.mlx))
+    }
+
+    @Test("OnDeviceProviderType raw values are descriptive")
+    func providerTypeRawValues() {
+        #expect(OnDeviceProviderType.coreML.rawValue == "coreML")
+        #expect(OnDeviceProviderType.mlx.rawValue == "mlx")
+    }
+
+    // MARK: - CoreML Configuration
+
+    @Test("CoreML configuration stores all properties")
+    func coreMLBasicConfiguration() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.mlmodelc")
+        let config = CoreMLProviderConfiguration(
+            modelURL: url,
+            computeUnits: .cpuAndGPU,
+            maxResponseTokens: 1024,
+            useSampling: true,
+            temperature: 0.3
+        )
+
+        #expect(config.modelURL == url)
+        #expect(config.computeUnits == .cpuAndGPU)
+        #expect(config.maxResponseTokens == 1024)
+        #expect(config.useSampling == true)
+        #expect(config.temperature == 0.3)
+    }
+
+    @Test("CoreML configuration uses sensible defaults")
+    func coreMLDefaultConfiguration() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.mlmodelc")
+        let config = CoreMLProviderConfiguration(modelURL: url)
+
+        #expect(config.computeUnits == .all)
+        #expect(config.maxResponseTokens == 2048)
+        #expect(config.useSampling == false)
+        #expect(config.temperature == 0.1)
+    }
+
+    @Test("CoreML validation fails for non-mlmodelc extension")
+    func coreMLValidateWrongExtension() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.onnx")
+        let config = CoreMLProviderConfiguration(modelURL: url)
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try config.validate()
+        }
+    }
+
+    @Test("CoreML validation fails for missing model file")
+    func coreMLValidateMissingFile() {
+        let url = URL(fileURLWithPath: "/nonexistent/path/Model.mlmodelc")
+        let config = CoreMLProviderConfiguration(modelURL: url)
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try config.validate()
+        }
+    }
+
+    @Test("CoreML configuration is Equatable")
+    func coreMLEquatable() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.mlmodelc")
+        let a = CoreMLProviderConfiguration(modelURL: url, computeUnits: .all)
+        let b = CoreMLProviderConfiguration(modelURL: url, computeUnits: .all)
+        let c = CoreMLProviderConfiguration(modelURL: url, computeUnits: .cpuOnly)
+
+        #expect(a == b)
+        #expect(a != c)
+    }
+
+    // MARK: - ComputeUnitPreference
+
+    @Test("ComputeUnitPreference has all expected cases")
+    func computeUnitCases() {
+        let cases = ComputeUnitPreference.allCases
+        #expect(cases.count == 4)
+        #expect(cases.contains(.all))
+        #expect(cases.contains(.cpuOnly))
+        #expect(cases.contains(.cpuAndGPU))
+        #expect(cases.contains(.cpuAndNeuralEngine))
+    }
+
+    // MARK: - MLX Configuration
+
+    @Test("MLX configuration stores all properties")
+    func mlxBasicConfiguration() {
+        let dir = URL(fileURLWithPath: "/tmp/models/my-model")
+        let config = MLXProviderConfiguration(
+            modelId: "mlx-community/Test-Model-4bit",
+            localDirectory: dir,
+            gpuMemory: .minimal,
+            maxResponseTokens: 512,
+            temperature: 0.2,
+            topP: 0.9,
+            repetitionPenalty: 1.2
+        )
+
+        #expect(config.modelId == "mlx-community/Test-Model-4bit")
+        #expect(config.localDirectory == dir)
+        #expect(config.gpuMemory == .minimal)
+        #expect(config.maxResponseTokens == 512)
+        #expect(config.temperature == 0.2)
+        #expect(config.topP == 0.9)
+        #expect(config.repetitionPenalty == 1.2)
+    }
+
+    @Test("MLX configuration uses sensible defaults")
+    func mlxDefaultConfiguration() {
+        let config = MLXProviderConfiguration(modelId: "test-model")
+
+        #expect(config.localDirectory == nil)
+        #expect(config.gpuMemory == .automatic)
+        #expect(config.maxResponseTokens == 2048)
+        #expect(config.temperature == 0.1)
+        #expect(config.topP == 0.95)
+        #expect(config.repetitionPenalty == 1.1)
+    }
+
+    @Test("MLX validation fails for empty model ID")
+    func mlxValidateEmptyModelId() {
+        let config = MLXProviderConfiguration(modelId: "")
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try config.validate()
+        }
+    }
+
+    @Test("MLX validation fails for nonexistent local directory")
+    func mlxValidateMissingDirectory() {
+        let config = MLXProviderConfiguration(
+            modelId: "test-model",
+            localDirectory: URL(fileURLWithPath: "/nonexistent/directory")
+        )
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try config.validate()
+        }
+    }
+
+    @Test("MLX validation fails for negative temperature")
+    func mlxValidateNegativeTemperature() {
+        let config = MLXProviderConfiguration(
+            modelId: "test-model",
+            temperature: -0.5
+        )
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try config.validate()
+        }
+    }
+
+    @Test("MLX validation fails for topP out of range")
+    func mlxValidateInvalidTopP() {
+        let configZero = MLXProviderConfiguration(
+            modelId: "test-model",
+            topP: 0.0
+        )
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try configZero.validate()
+        }
+
+        let configOver = MLXProviderConfiguration(
+            modelId: "test-model",
+            topP: 1.5
+        )
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try configOver.validate()
+        }
+    }
+
+    @Test("MLX validation fails for zero repetition penalty")
+    func mlxValidateInvalidRepetitionPenalty() {
+        let config = MLXProviderConfiguration(
+            modelId: "test-model",
+            repetitionPenalty: 0.0
+        )
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try config.validate()
+        }
+    }
+
+    @Test("MLX validation succeeds for valid configuration")
+    func mlxValidateSuccess() throws {
+        let config = MLXProviderConfiguration(modelId: "test-model")
+        // Should not throw (no local directory set, model ID is non-empty)
+        try config.validate()
+    }
+
+    @Test("MLX configuration is Equatable")
+    func mlxEquatable() {
+        let a = MLXProviderConfiguration(modelId: "model-a")
+        let b = MLXProviderConfiguration(modelId: "model-a")
+        let c = MLXProviderConfiguration(modelId: "model-b")
+
+        #expect(a == b)
+        #expect(a != c)
+    }
+
+    // MARK: - Well-Known MLX Models
+
+    @Test("Llama 3.2 3B preset has correct model ID")
+    func llama3_2_3BPreset() {
+        let config = MLXProviderConfiguration.llama3_2_3B()
+        #expect(config.modelId == "mlx-community/Llama-3.2-3B-Instruct-4bit")
+        #expect(config.temperature == 0.1)
+        #expect(config.maxResponseTokens == 2048)
+    }
+
+    @Test("Qwen 2.5 Coder 3B preset has correct model ID")
+    func qwen2_5_coder3BPreset() {
+        let config = MLXProviderConfiguration.qwen2_5_coder_3B()
+        #expect(config.modelId == "mlx-community/Qwen2.5-Coder-3B-Instruct-4bit")
+        #expect(config.temperature == 0.05)
+    }
+
+    @Test("Phi 3.5 Mini preset has correct model ID")
+    func phi3_5_miniPreset() {
+        let config = MLXProviderConfiguration.phi3_5_mini()
+        #expect(config.modelId == "mlx-community/Phi-3.5-mini-instruct-4bit")
+        #expect(config.temperature == 0.1)
+    }
+
+    @Test("Well-known models accept custom GPU memory config")
+    func wellKnownModelsCustomGPU() {
+        let config = MLXProviderConfiguration.llama3_2_3B(
+            gpuMemory: .minimal
+        )
+        #expect(config.gpuMemory == .minimal)
+    }
+
+    // MARK: - GPU Memory Configuration
+
+    @Test("Automatic GPU memory config scales with RAM")
+    func automaticGPUMemory() {
+        let config = MLXGPUMemoryConfig.automatic
+        #expect(config.activeCacheLimit > 0)
+        #expect(config.idleCacheLimit == 50_000_000)
+        #expect(config.clearCacheOnEviction == true)
+    }
+
+    @Test("Minimal GPU memory config is conservative")
+    func minimalGPUMemory() {
+        let config = MLXGPUMemoryConfig.minimal
+        #expect(config.activeCacheLimit == 64_000_000)
+        #expect(config.idleCacheLimit == 16_000_000)
+        #expect(config.clearCacheOnEviction == true)
+    }
+
+    @Test("Unconstrained GPU memory config uses max values")
+    func unconstrainedGPUMemory() {
+        let config = MLXGPUMemoryConfig.unconstrained
+        #expect(config.activeCacheLimit == Int.max)
+        #expect(config.idleCacheLimit == Int.max)
+        #expect(config.clearCacheOnEviction == false)
+    }
+
+    @Test("GPU memory config is Equatable")
+    func gpuMemoryEquatable() {
+        #expect(MLXGPUMemoryConfig.minimal == MLXGPUMemoryConfig.minimal)
+        #expect(MLXGPUMemoryConfig.minimal != MLXGPUMemoryConfig.unconstrained)
+    }
+
+    // MARK: - On-Device Provider Errors
+
+    @Test("OnDeviceProviderError has descriptive messages")
+    func errorDescriptions() {
+        let errors: [OnDeviceProviderError] = [
+            .modelNotFound(URL(fileURLWithPath: "/tmp/model")),
+            .invalidModelFormat(expected: ".mlmodelc", actual: ".onnx"),
+            .emptyModelId,
+            .invalidParameter(name: "temperature", value: "-1", reason: "Must be non-negative"),
+            .providerUnavailable(.mlx, reason: "MLX build flag not enabled"),
+            .modelLoadFailed(reason: "Out of memory"),
+            .inferenceFailed(reason: "Token limit exceeded"),
+        ]
+
+        for error in errors {
+            #expect(error.errorDescription != nil)
+            #expect(!error.errorDescription!.isEmpty)
+        }
+    }
+
+    @Test("OnDeviceProviderError is Equatable")
+    func errorEquatable() {
+        let a = OnDeviceProviderError.emptyModelId
+        let b = OnDeviceProviderError.emptyModelId
+        let c = OnDeviceProviderError.modelLoadFailed(reason: "test")
+
+        #expect(a == b)
+        #expect(a != c)
+    }
+
+    // MARK: - Inference Pipeline
+
+    @Test("MLX inference pipeline initializes with correct type")
+    func mlxPipelineInit() {
+        let config = MLXProviderConfiguration.llama3_2_3B()
+        let pipeline = OnDeviceInferencePipeline(mlxConfiguration: config)
+
+        #expect(pipeline.providerType == .mlx)
+        #expect(pipeline.mlxConfiguration != nil)
+        #expect(pipeline.coreMLConfiguration == nil)
+        #expect(pipeline.status == .notLoaded)
+    }
+
+    @Test("CoreML inference pipeline initializes with correct type")
+    func coreMLPipelineInit() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.mlmodelc")
+        let config = CoreMLProviderConfiguration(modelURL: url)
+        let pipeline = OnDeviceInferencePipeline(coreMLConfiguration: config)
+
+        #expect(pipeline.providerType == .coreML)
+        #expect(pipeline.coreMLConfiguration != nil)
+        #expect(pipeline.mlxConfiguration == nil)
+        #expect(pipeline.status == .notLoaded)
+    }
+
+    @Test("Pipeline validates MLX configuration")
+    func pipelineValidatesMLX() throws {
+        let validConfig = MLXProviderConfiguration(modelId: "test-model")
+        let pipeline = OnDeviceInferencePipeline(mlxConfiguration: validConfig)
+        try pipeline.validateConfiguration()
+
+        let invalidConfig = MLXProviderConfiguration(modelId: "")
+        let invalidPipeline = OnDeviceInferencePipeline(mlxConfiguration: invalidConfig)
+        #expect(throws: OnDeviceProviderError.self) {
+            try invalidPipeline.validateConfiguration()
+        }
+    }
+
+    @Test("Pipeline validates CoreML configuration")
+    func pipelineValidatesCoreML() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.onnx")
+        let config = CoreMLProviderConfiguration(modelURL: url)
+        let pipeline = OnDeviceInferencePipeline(coreMLConfiguration: config)
+
+        #expect(throws: OnDeviceProviderError.self) {
+            try pipeline.validateConfiguration()
+        }
+    }
+
+    @Test("Pipeline provides SQL generation hints for MLX")
+    func mlxSQLHints() {
+        let config = MLXProviderConfiguration(
+            modelId: "test-model",
+            maxResponseTokens: 512,
+            temperature: 0.2
+        )
+        let pipeline = OnDeviceInferencePipeline(mlxConfiguration: config)
+        let hints = pipeline.recommendedSQLGenerationHints
+
+        #expect(hints.maxTokens == 512)
+        #expect(hints.temperature == 0.2)
+        #expect(hints.useSampling == true)
+        #expect(hints.systemPromptSuffix.contains("MLX"))
+    }
+
+    @Test("Pipeline provides SQL generation hints for CoreML")
+    func coreMLSQLHints() {
+        let url = URL(fileURLWithPath: "/tmp/TestModel.mlmodelc")
+        let config = CoreMLProviderConfiguration(
+            modelURL: url,
+            maxResponseTokens: 1024,
+            useSampling: false,
+            temperature: 0.05
+        )
+        let pipeline = OnDeviceInferencePipeline(coreMLConfiguration: config)
+        let hints = pipeline.recommendedSQLGenerationHints
+
+        #expect(hints.maxTokens == 1024)
+        #expect(hints.temperature == 0.05)
+        #expect(hints.useSampling == false)
+        #expect(hints.systemPromptSuffix.contains("SQL"))
+    }
+
+    // MARK: - System Readiness
+
+    @Test("System capability check returns valid data")
+    func systemCapability() {
+        let capability = OnDeviceModelReadiness.checkSystemCapability()
+
+        #expect(capability.totalRAM > 0)
+        // On any modern test machine, we should have at least some RAM
+        #expect(capability.totalRAM > 1024 * 1024 * 1024) // > 1GB
+
+        // On Apple silicon Macs, this should be true
+        #if arch(arm64)
+            #expect(capability.hasNeuralEngine == true)
+        #endif
+    }
+
+    @Test("Suggested MLX model returns a valid configuration")
+    func suggestedMLXModel() {
+        let config = OnDeviceModelReadiness.suggestedMLXModel()
+        #expect(!config.modelId.isEmpty)
+        #expect(config.temperature >= 0)
+        #expect(config.maxResponseTokens > 0)
+    }
+
+    @Test("Recommended model size enum has correct raw values")
+    func recommendedModelSizeRawValues() {
+        #expect(OnDeviceModelReadiness.RecommendedModelSize.small.rawValue == "small")
+        #expect(OnDeviceModelReadiness.RecommendedModelSize.medium.rawValue == "medium")
+        #expect(OnDeviceModelReadiness.RecommendedModelSize.large.rawValue == "large")
+    }
+
+    // MARK: - ProviderConfiguration Integration
+
+    @Test("onDeviceMLX creates a ProviderConfiguration")
+    func onDeviceMLXProviderConfig() {
+        let mlxConfig = MLXProviderConfiguration.llama3_2_3B()
+        let providerConfig = ProviderConfiguration.onDeviceMLX(mlxConfig)
+
+        #expect(providerConfig.model == mlxConfig.modelId)
+        #expect(!providerConfig.hasValidAPIKey) // No API key needed for on-device
+    }
+
+    @Test("onDeviceCoreML creates a ProviderConfiguration")
+    func onDeviceCoreMLProviderConfig() {
+        let url = URL(fileURLWithPath: "/tmp/SQLModel.mlmodelc")
+        let coreMLConfig = CoreMLProviderConfiguration(modelURL: url)
+        let providerConfig = ProviderConfiguration.onDeviceCoreML(coreMLConfig)
+
+        #expect(providerConfig.model == "SQLModel.mlmodelc")
+        #expect(!providerConfig.hasValidAPIKey)
+    }
+
+    // MARK: - Pipeline Status
+
+    @Test("Pipeline status transitions")
+    func pipelineStatusTransitions() {
+        let config = MLXProviderConfiguration(modelId: "test-model")
+        let pipeline = OnDeviceInferencePipeline(mlxConfiguration: config)
+
+        #expect(pipeline.status == .notLoaded)
+
+        pipeline.setStatus(.loading)
+        #expect(pipeline.status == .loading)
+
+        pipeline.setStatus(.ready)
+        #expect(pipeline.status == .ready)
+
+        pipeline.setStatus(.failed("Out of memory"))
+        #expect(pipeline.status == .failed("Out of memory"))
+    }
+
+    @Test("Pipeline Status is Equatable")
+    func pipelineStatusEquatable() {
+        #expect(OnDeviceInferencePipeline.Status.notLoaded == .notLoaded)
+        #expect(OnDeviceInferencePipeline.Status.loading == .loading)
+        #expect(OnDeviceInferencePipeline.Status.ready == .ready)
+        #expect(OnDeviceInferencePipeline.Status.failed("a") == .failed("a"))
+        #expect(OnDeviceInferencePipeline.Status.failed("a") != .failed("b"))
+        #expect(OnDeviceInferencePipeline.Status.notLoaded != .ready)
+    }
+
+    // MARK: - SQL Generation Hints
+
+    @Test("SQL generation hints are Equatable")
+    func sqlHintsEquatable() {
+        let a = OnDeviceSQLGenerationHints(
+            maxTokens: 512,
+            temperature: 0.1,
+            systemPromptSuffix: "test",
+            useSampling: true
+        )
+        let b = OnDeviceSQLGenerationHints(
+            maxTokens: 512,
+            temperature: 0.1,
+            systemPromptSuffix: "test",
+            useSampling: true
+        )
+        let c = OnDeviceSQLGenerationHints(
+            maxTokens: 1024,
+            temperature: 0.1,
+            systemPromptSuffix: "test",
+            useSampling: true
+        )
+
+        #expect(a == b)
+        #expect(a != c)
+    }
+}

Tests/SwiftDBAITests/PromptBuilderTests.swift

@@ -0,0 +1,254 @@
+// PromptBuilderTests.swift
+// SwiftDBAI
+
+import Testing
+@testable import SwiftDBAI
+
+@Suite("PromptBuilder")
+struct PromptBuilderTests {
+
+    // MARK: - Helpers
+
+    /// Creates a sample schema for testing.
+    private func makeSampleSchema() -> DatabaseSchema {
+        let usersTable = TableSchema(
+            name: "users",
+            columns: [
+                ColumnSchema(cid: 0, name: "id", type: "INTEGER", isNotNull: true, defaultValue: nil, isPrimaryKey: true),
+                ColumnSchema(cid: 1, name: "name", type: "TEXT", isNotNull: true, defaultValue: nil, isPrimaryKey: false),
+                ColumnSchema(cid: 2, name: "email", type: "TEXT", isNotNull: false, defaultValue: nil, isPrimaryKey: false),
+                ColumnSchema(cid: 3, name: "created_at", type: "TEXT", isNotNull: false, defaultValue: "CURRENT_TIMESTAMP", isPrimaryKey: false),
+            ],
+            primaryKey: ["id"],
+            foreignKeys: [],
+            indexes: [
+                IndexSchema(name: "idx_users_email", isUnique: true, columns: ["email"])
+            ]
+        )
+
+        let ordersTable = TableSchema(
+            name: "orders",
+            columns: [
+                ColumnSchema(cid: 0, name: "id", type: "INTEGER", isNotNull: true, defaultValue: nil, isPrimaryKey: true),
+                ColumnSchema(cid: 1, name: "user_id", type: "INTEGER", isNotNull: true, defaultValue: nil, isPrimaryKey: false),
+                ColumnSchema(cid: 2, name: "total", type: "REAL", isNotNull: true, defaultValue: nil, isPrimaryKey: false),
+                ColumnSchema(cid: 3, name: "status", type: "TEXT", isNotNull: true, defaultValue: "'pending'", isPrimaryKey: false),
+            ],
+            primaryKey: ["id"],
+            foreignKeys: [
+                ForeignKeySchema(fromColumn: "user_id", toTable: "users", toColumn: "id", onUpdate: "NO ACTION", onDelete: "CASCADE")
+            ],
+            indexes: []
+        )
+
+        return DatabaseSchema(
+            tables: ["users": usersTable, "orders": ordersTable],
+            tableNames: ["users", "orders"]
+        )
+    }
+
+    private func makeEmptySchema() -> DatabaseSchema {
+        DatabaseSchema(tables: [:], tableNames: [])
+    }
+
+    // MARK: - System Instructions Tests
+
+    @Test("System instructions contain role section")
+    func systemInstructionsContainRole() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("ROLE"))
+        #expect(instructions.contains("SQL assistant"))
+        #expect(instructions.contains("SQLite database"))
+    }
+
+    @Test("System instructions contain schema")
+    func systemInstructionsContainSchema() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("DATABASE SCHEMA"))
+        #expect(instructions.contains("TABLE users"))
+        #expect(instructions.contains("TABLE orders"))
+        #expect(instructions.contains("name TEXT"))
+        #expect(instructions.contains("email TEXT"))
+    }
+
+    @Test("System instructions contain foreign keys from schema")
+    func systemInstructionsContainForeignKeys() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("FOREIGN KEY"))
+        #expect(instructions.contains("REFERENCES users(id)"))
+    }
+
+    @Test("System instructions contain SQL generation rules")
+    func systemInstructionsContainRules() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("SQL GENERATION RULES"))
+        #expect(instructions.contains("Use ONLY the tables and columns"))
+        #expect(instructions.contains("Never generate DDL"))
+    }
+
+    @Test("System instructions contain output format section")
+    func systemInstructionsContainOutputFormat() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("OUTPUT FORMAT"))
+    }
+
+    @Test("Default allowlist is read-only")
+    func defaultAllowlistIsReadOnly() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("ONLY generate SELECT queries"))
+        #expect(instructions.contains("No data modifications"))
+    }
+
+    @Test("Standard allowlist shows correct operations")
+    func standardAllowlistInstructions() {
+        let builder = PromptBuilder(schema: makeSampleSchema(), allowlist: .standard)
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("INSERT"))
+        #expect(instructions.contains("SELECT"))
+        #expect(instructions.contains("UPDATE"))
+    }
+
+    @Test("Unrestricted allowlist warns about DELETE")
+    func unrestrictedAllowlistWarnsAboutDelete() {
+        let builder = PromptBuilder(schema: makeSampleSchema(), allowlist: .unrestricted)
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("DELETE"))
+        #expect(instructions.contains("destructive"))
+        #expect(instructions.contains("confirmation"))
+    }
+
+    @Test("Additional context is appended")
+    func additionalContextAppended() {
+        let builder = PromptBuilder(
+            schema: makeSampleSchema(),
+            additionalContext: "All dates are stored in ISO 8601 format."
+        )
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("ADDITIONAL CONTEXT"))
+        #expect(instructions.contains("ISO 8601"))
+    }
+
+    @Test("No additional context section when nil")
+    func noAdditionalContextWhenNil() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(!instructions.contains("ADDITIONAL CONTEXT"))
+    }
+
+    @Test("No additional context section when empty string")
+    func noAdditionalContextWhenEmpty() {
+        let builder = PromptBuilder(schema: makeSampleSchema(), additionalContext: "")
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(!instructions.contains("ADDITIONAL CONTEXT"))
+    }
+
+    @Test("Empty schema produces valid instructions")
+    func emptySchemaProducesValidInstructions() {
+        let builder = PromptBuilder(schema: makeEmptySchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("ROLE"))
+        #expect(instructions.contains("SQL GENERATION RULES"))
+        // Schema section should still be present, just empty
+        #expect(instructions.contains("DATABASE SCHEMA"))
+    }
+
+    // MARK: - User Prompt Tests
+
+    @Test("User prompt passes through question directly")
+    func userPromptPassesThrough() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let prompt = builder.buildUserPrompt("How many users signed up this week?")
+
+        #expect(prompt == "How many users signed up this week?")
+    }
+
+    // MARK: - Follow-up Prompt Tests
+
+    @Test("Follow-up prompt includes previous context")
+    func followUpPromptIncludesPreviousContext() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let prompt = builder.buildFollowUpPrompt(
+            "Now sort them by name",
+            previousSQL: "SELECT * FROM users WHERE created_at > date('now', '-7 days')",
+            previousResultSummary: "Found 42 users who signed up this week"
+        )
+
+        #expect(prompt.contains("Previous query:"))
+        #expect(prompt.contains("SELECT * FROM users"))
+        #expect(prompt.contains("Previous result:"))
+        #expect(prompt.contains("42 users"))
+        #expect(prompt.contains("Follow-up question:"))
+        #expect(prompt.contains("sort them by name"))
+    }
+
+    // MARK: - Schema Description Quality
+
+    @Test("Schema includes column types and constraints")
+    func schemaIncludesColumnDetails() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        // Should include type info
+        #expect(instructions.contains("INTEGER"))
+        #expect(instructions.contains("TEXT"))
+        #expect(instructions.contains("REAL"))
+
+        // Should include constraints
+        #expect(instructions.contains("NOT NULL"))
+        #expect(instructions.contains("PRIMARY KEY"))
+    }
+
+    @Test("Schema includes index information")
+    func schemaIncludesIndexes() {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("INDEX"))
+        #expect(instructions.contains("idx_users_email"))
+    }
+
+    // MARK: - Sendable Conformance
+
+    @Test("PromptBuilder is Sendable")
+    func promptBuilderIsSendable() async {
+        let builder = PromptBuilder(schema: makeSampleSchema())
+
+        // Verify it can be sent across concurrency boundaries
+        let instructions = await Task.detached {
+            builder.buildSystemInstructions()
+        }.value
+
+        #expect(instructions.contains("ROLE"))
+    }
+
+    // MARK: - Custom Allowlist
+
+    @Test("Custom allowlist with select and delete only")
+    func customAllowlist() {
+        let allowlist = OperationAllowlist([.select, .delete])
+        let builder = PromptBuilder(schema: makeSampleSchema(), allowlist: allowlist)
+        let instructions = builder.buildSystemInstructions()
+
+        #expect(instructions.contains("DELETE"))
+        #expect(instructions.contains("SELECT"))
+        #expect(instructions.contains("destructive"))
+    }
+}

Tests/SwiftDBAITests/ProviderConfigurationTests.swift

@@ -0,0 +1,325 @@
+// ProviderConfigurationTests.swift
+// SwiftDBAI Tests
+//
+// Tests for ProviderConfiguration — verifying all cloud provider configurations
+// produce valid LanguageModel instances with correct settings.
+
+import AnyLanguageModel
+import Foundation
+@testable import SwiftDBAI
+import Testing
+
+@Suite("ProviderConfiguration")
+struct ProviderConfigurationTests {
+
+    // MARK: - OpenAI Configuration
+
+    @Test("OpenAI configuration stores provider and model")
+    func openAIBasicConfiguration() {
+        let config = ProviderConfiguration.openAI(
+            apiKey: "sk-test-key-123",
+            model: "gpt-4o"
+        )
+
+        #expect(config.provider == .openAI)
+        #expect(config.model == "gpt-4o")
+        #expect(config.apiKey == "sk-test-key-123")
+        #expect(config.hasValidAPIKey)
+    }
+
+    @Test("OpenAI configuration produces a valid LanguageModel")
+    func openAIMakeModel() {
+        let config = ProviderConfiguration.openAI(
+            apiKey: "sk-test-key",
+            model: "gpt-4o-mini"
+        )
+
+        let model = config.makeModel()
+        #expect(model is OpenAILanguageModel)
+    }
+
+    @Test("OpenAI with custom base URL for compatible services")
+    func openAICustomBaseURL() {
+        let customURL = URL(string: "https://my-proxy.example.com/v1/")!
+        let config = ProviderConfiguration.openAI(
+            apiKey: "sk-proxy-key",
+            model: "gpt-4o",
+            baseURL: customURL
+        )
+
+        #expect(config.baseURL == customURL)
+        let model = config.makeModel()
+        #expect(model is OpenAILanguageModel)
+    }
+
+    @Test("OpenAI with Responses API variant")
+    func openAIResponsesVariant() {
+        let config = ProviderConfiguration.openAI(
+            apiKey: "sk-test",
+            model: "gpt-4o",
+            variant: .responses
+        )
+
+        #expect(config.openAIVariant == .responses)
+        let model = config.makeModel()
+        #expect(model is OpenAILanguageModel)
+    }
+
+    @Test("OpenAI with dynamic key provider captures key by reference")
+    func openAIDynamicKeyProvider() {
+        nonisolated(unsafe) var currentKey = "sk-initial"
+        let config = ProviderConfiguration.openAI(
+            apiKeyProvider: { currentKey },
+            model: "gpt-4o"
+        )
+
+        #expect(config.apiKey == "sk-initial")
+        currentKey = "sk-rotated"
+        #expect(config.apiKey == "sk-rotated")
+    }
+
+    // MARK: - Anthropic Configuration
+
+    @Test("Anthropic configuration stores provider and model")
+    func anthropicBasicConfiguration() {
+        let config = ProviderConfiguration.anthropic(
+            apiKey: "sk-ant-test-key",
+            model: "claude-sonnet-4-20250514"
+        )
+
+        #expect(config.provider == .anthropic)
+        #expect(config.model == "claude-sonnet-4-20250514")
+        #expect(config.apiKey == "sk-ant-test-key")
+        #expect(config.hasValidAPIKey)
+    }
+
+    @Test("Anthropic configuration produces a valid LanguageModel")
+    func anthropicMakeModel() {
+        let config = ProviderConfiguration.anthropic(
+            apiKey: "sk-ant-test",
+            model: "claude-sonnet-4-20250514"
+        )
+
+        let model = config.makeModel()
+        #expect(model is AnthropicLanguageModel)
+    }
+
+    @Test("Anthropic with API version and betas")
+    func anthropicWithVersionAndBetas() {
+        let config = ProviderConfiguration.anthropic(
+            apiKey: "sk-ant-test",
+            model: "claude-sonnet-4-20250514",
+            apiVersion: "2024-01-01",
+            betas: ["computer-use"]
+        )
+
+        #expect(config.apiVersion == "2024-01-01")
+        #expect(config.betas == ["computer-use"])
+        let model = config.makeModel()
+        #expect(model is AnthropicLanguageModel)
+    }
+
+    @Test("Anthropic with dynamic key provider captures key by reference")
+    func anthropicDynamicKeyProvider() {
+        nonisolated(unsafe) var currentKey = "sk-ant-initial"
+        let config = ProviderConfiguration.anthropic(
+            apiKeyProvider: { currentKey },
+            model: "claude-sonnet-4-20250514"
+        )
+
+        #expect(config.apiKey == "sk-ant-initial")
+        currentKey = "sk-ant-rotated"
+        #expect(config.apiKey == "sk-ant-rotated")
+    }
+
+    // MARK: - Gemini Configuration
+
+    @Test("Gemini configuration stores provider and model")
+    func geminiBasicConfiguration() {
+        let config = ProviderConfiguration.gemini(
+            apiKey: "AIzaSyTest123",
+            model: "gemini-2.0-flash"
+        )
+
+        #expect(config.provider == .gemini)
+        #expect(config.model == "gemini-2.0-flash")
+        #expect(config.apiKey == "AIzaSyTest123")
+        #expect(config.hasValidAPIKey)
+    }
+
+    @Test("Gemini configuration produces a valid LanguageModel")
+    func geminiMakeModel() {
+        let config = ProviderConfiguration.gemini(
+            apiKey: "AIzaSyTest",
+            model: "gemini-2.0-flash"
+        )
+
+        let model = config.makeModel()
+        #expect(model is GeminiLanguageModel)
+    }
+
+    @Test("Gemini with custom API version")
+    func geminiCustomVersion() {
+        let config = ProviderConfiguration.gemini(
+            apiKey: "AIzaSyTest",
+            model: "gemini-2.0-flash",
+            apiVersion: "v1"
+        )
+
+        #expect(config.apiVersion == "v1")
+        let model = config.makeModel()
+        #expect(model is GeminiLanguageModel)
+    }
+
+    @Test("Gemini with dynamic key provider captures key by reference")
+    func geminiDynamicKeyProvider() {
+        nonisolated(unsafe) var currentKey = "AIza-initial"
+        let config = ProviderConfiguration.gemini(
+            apiKeyProvider: { currentKey },
+            model: "gemini-2.0-flash"
+        )
+
+        #expect(config.apiKey == "AIza-initial")
+        currentKey = "AIza-rotated"
+        #expect(config.apiKey == "AIza-rotated")
+    }
+
+    // MARK: - OpenAI-Compatible Configuration
+
+    @Test("OpenAI-compatible configuration with custom base URL")
+    func openAICompatibleConfiguration() {
+        let baseURL = URL(string: "https://api.together.xyz/v1/")!
+        let config = ProviderConfiguration.openAICompatible(
+            apiKey: "together-key",
+            model: "meta-llama/Llama-3.1-70B",
+            baseURL: baseURL
+        )
+
+        #expect(config.provider == .openAICompatible)
+        #expect(config.model == "meta-llama/Llama-3.1-70B")
+        #expect(config.baseURL == baseURL)
+        let model = config.makeModel()
+        #expect(model is OpenAILanguageModel)
+    }
+
+    @Test("OpenAI-compatible with dynamic key provider")
+    func openAICompatibleDynamicKey() {
+        let baseURL = URL(string: "http://localhost:1234/v1/")!
+        nonisolated(unsafe) var currentKey = "local-key"
+        let config = ProviderConfiguration.openAICompatible(
+            apiKeyProvider: { currentKey },
+            model: "local-model",
+            baseURL: baseURL
+        )
+
+        #expect(config.apiKey == "local-key")
+        currentKey = "new-local-key"
+        #expect(config.apiKey == "new-local-key")
+    }
+
+    // MARK: - API Key Validation
+
+    @Test("Empty API key reports invalid")
+    func emptyAPIKeyInvalid() {
+        let config = ProviderConfiguration.openAI(
+            apiKey: "",
+            model: "gpt-4o"
+        )
+
+        #expect(!config.hasValidAPIKey)
+    }
+
+    @Test("Whitespace-only API key reports invalid")
+    func whitespaceAPIKeyInvalid() {
+        let config = ProviderConfiguration.openAI(
+            apiKey: "   \n\t  ",
+            model: "gpt-4o"
+        )
+
+        #expect(!config.hasValidAPIKey)
+    }
+
+    @Test("Non-empty API key reports valid")
+    func nonEmptyAPIKeyValid() {
+        let config = ProviderConfiguration.openAI(
+            apiKey: "x",
+            model: "gpt-4o"
+        )
+
+        #expect(config.hasValidAPIKey)
+    }
+
+    // MARK: - Environment Variable Configuration
+
+    @Test("fromEnvironment creates configuration for each provider")
+    func fromEnvironmentCreatesConfig() {
+        let openAI = ProviderConfiguration.fromEnvironment(
+            provider: .openAI,
+            environmentVariable: "SWIFTDAI_TEST_OPENAI_KEY",
+            model: "gpt-4o"
+        )
+        #expect(openAI.provider == .openAI)
+        #expect(openAI.model == "gpt-4o")
+
+        let anthropic = ProviderConfiguration.fromEnvironment(
+            provider: .anthropic,
+            environmentVariable: "SWIFTDAI_TEST_ANTHROPIC_KEY",
+            model: "claude-sonnet-4-20250514"
+        )
+        #expect(anthropic.provider == .anthropic)
+
+        let gemini = ProviderConfiguration.fromEnvironment(
+            provider: .gemini,
+            environmentVariable: "SWIFTDAI_TEST_GEMINI_KEY",
+            model: "gemini-2.0-flash"
+        )
+        #expect(gemini.provider == .gemini)
+    }
+
+    @Test("fromEnvironment returns empty key when variable not set")
+    func fromEnvironmentMissingVariable() {
+        let config = ProviderConfiguration.fromEnvironment(
+            provider: .openAI,
+            environmentVariable: "NONEXISTENT_KEY_VAR_SWIFTDBAI_TEST",
+            model: "gpt-4o"
+        )
+
+        #expect(!config.hasValidAPIKey)
+        #expect(config.apiKey == "")
+    }
+
+    // MARK: - Provider Enum
+
+    @Test("Provider enum has all expected cases")
+    func providerCases() {
+        let cases = ProviderConfiguration.Provider.allCases
+        #expect(cases.count == 6)
+        #expect(cases.contains(.openAI))
+        #expect(cases.contains(.anthropic))
+        #expect(cases.contains(.gemini))
+        #expect(cases.contains(.openAICompatible))
+        #expect(cases.contains(.ollama))
+        #expect(cases.contains(.llamaCpp))
+    }
+
+    // MARK: - Cross-Provider Model Creation
+
+    @Test("All providers produce available models")
+    func allProvidersCreateAvailableModels() {
+        let configs: [ProviderConfiguration] = [
+            .openAI(apiKey: "test", model: "gpt-4o"),
+            .anthropic(apiKey: "test", model: "claude-sonnet-4-20250514"),
+            .gemini(apiKey: "test", model: "gemini-2.0-flash"),
+            .openAICompatible(
+                apiKey: "test",
+                model: "local",
+                baseURL: URL(string: "http://localhost:8080/v1/")!
+            ),
+        ]
+
+        for config in configs {
+            let model = config.makeModel()
+            #expect(model.isAvailable, "Model for \(config.provider) should be available")
+        }
+    }
+}

Tests/SwiftDBAITests/SQLQueryParserTests.swift

@@ -0,0 +1,397 @@
+// SQLQueryParserTests.swift
+// SwiftDBAITests
+
+import Testing
+@testable import SwiftDBAI
+
+@Suite("SQLQueryParser")
+struct SQLQueryParserTests {
+
+    let readOnlyParser = SQLQueryParser(allowlist: .readOnly)
+    let standardParser = SQLQueryParser(allowlist: .standard)
+    let unrestrictedParser = SQLQueryParser(allowlist: .unrestricted)
+
+    // MARK: - Extraction from code blocks
+
+    @Test("Extracts SQL from markdown sql code block")
+    func extractFromSQLCodeBlock() throws {
+        let text = """
+        Here's the query to find the top users:
+
+        ```sql
+        SELECT name, COUNT(*) as count FROM users GROUP BY name ORDER BY count DESC
+        ```
+
+        This will give you the results.
+        """
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql == "SELECT name, COUNT(*) as count FROM users GROUP BY name ORDER BY count DESC")
+        #expect(result.operation == .select)
+        #expect(result.requiresConfirmation == false)
+    }
+
+    @Test("Extracts SQL from generic code block")
+    func extractFromGenericCodeBlock() throws {
+        let text = """
+        Here you go:
+
+        ```
+        SELECT * FROM products WHERE price > 100
+        ```
+        """
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql == "SELECT * FROM products WHERE price > 100")
+    }
+
+    @Test("Extracts SQL from labeled text")
+    func extractFromLabel() throws {
+        let text = """
+        I can help with that.
+        SQL: SELECT id, name FROM categories WHERE active = 1
+        That should work.
+        """
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql == "SELECT id, name FROM categories WHERE active = 1")
+    }
+
+    @Test("Extracts direct SQL from plain text")
+    func extractDirectSQL() throws {
+        let text = "SELECT COUNT(*) FROM orders WHERE status = 'shipped'"
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql == "SELECT COUNT(*) FROM orders WHERE status = 'shipped'")
+    }
+
+    @Test("Handles SQL with trailing semicolons")
+    func trailingSemicolon() throws {
+        let text = "```sql\nSELECT * FROM users;\n```"
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql == "SELECT * FROM users")
+    }
+
+    @Test("Handles multiline SQL in code block")
+    func multilineSQL() throws {
+        let text = """
+        ```sql
+        SELECT u.name, COUNT(o.id) as order_count
+        FROM users u
+        JOIN orders o ON u.id = o.user_id
+        GROUP BY u.name
+        ORDER BY order_count DESC
+        LIMIT 10
+        ```
+        """
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql.contains("SELECT u.name"))
+        #expect(result.sql.contains("LIMIT 10"))
+    }
+
+    @Test("Handles WITH (CTE) queries as SELECT")
+    func cteQuery() throws {
+        let text = """
+        ```sql
+        WITH top_users AS (
+          SELECT user_id, COUNT(*) as cnt FROM orders GROUP BY user_id
+        )
+        SELECT * FROM top_users WHERE cnt > 5
+        ```
+        """
+        let result = try readOnlyParser.parse(text)
+        #expect(result.operation == .select)
+    }
+
+    // MARK: - No SQL found
+
+    @Test("Throws noSQLFound for text without SQL")
+    func noSQLFound() throws {
+        let text = "I'm sorry, I can't help with that request."
+        #expect(throws: SQLParsingError.noSQLFound) {
+            try readOnlyParser.parse(text)
+        }
+    }
+
+    @Test("Throws noSQLFound for empty input")
+    func emptyInput() throws {
+        #expect(throws: SQLParsingError.noSQLFound) {
+            try readOnlyParser.parse("")
+        }
+    }
+
+    // MARK: - Operation detection
+
+    @Test("Detects INSERT operation")
+    func detectInsert() throws {
+        let text = "```sql\nINSERT INTO users (name) VALUES ('Alice')\n```"
+        let result = try standardParser.parse(text)
+        #expect(result.operation == .insert)
+    }
+
+    @Test("Detects UPDATE operation")
+    func detectUpdate() throws {
+        let text = "```sql\nUPDATE users SET name = 'Bob' WHERE id = 1\n```"
+        let result = try standardParser.parse(text)
+        #expect(result.operation == .update)
+    }
+
+    @Test("Detects DELETE operation and requires confirmation")
+    func detectDeleteRequiresConfirmation() throws {
+        let text = "```sql\nDELETE FROM users WHERE id = 99\n```"
+        let result = try unrestrictedParser.parse(text)
+        #expect(result.operation == .delete)
+        #expect(result.requiresConfirmation == true)
+    }
+
+    // MARK: - Allowlist enforcement
+
+    @Test("Rejects INSERT on read-only allowlist")
+    func rejectInsertOnReadOnly() throws {
+        let text = "```sql\nINSERT INTO users (name) VALUES ('Mallory')\n```"
+        #expect(throws: SQLParsingError.operationNotAllowed(.insert)) {
+            try readOnlyParser.parse(text)
+        }
+    }
+
+    @Test("Rejects UPDATE on read-only allowlist")
+    func rejectUpdateOnReadOnly() {
+        let text = "```sql\nUPDATE users SET name = 'Eve' WHERE id = 1\n```"
+        #expect(throws: SQLParsingError.operationNotAllowed(.update)) {
+            try readOnlyParser.parse(text)
+        }
+    }
+
+    @Test("Rejects DELETE on standard allowlist")
+    func rejectDeleteOnStandard() {
+        let text = "```sql\nDELETE FROM users WHERE id = 1\n```"
+        #expect(throws: SQLParsingError.operationNotAllowed(.delete)) {
+            try standardParser.parse(text)
+        }
+    }
+
+    // MARK: - Dangerous operations
+
+    @Test("Rejects DROP TABLE")
+    func rejectDrop() {
+        let text = "```sql\nDROP TABLE users\n```"
+        #expect(throws: SQLParsingError.dangerousOperation("DROP")) {
+            try unrestrictedParser.parse(text)
+        }
+    }
+
+    @Test("Rejects ALTER TABLE")
+    func rejectAlter() {
+        let text = "```sql\nALTER TABLE users ADD COLUMN age INTEGER\n```"
+        #expect(throws: SQLParsingError.dangerousOperation("ALTER")) {
+            try unrestrictedParser.parse(text)
+        }
+    }
+
+    @Test("Rejects PRAGMA")
+    func rejectPragma() {
+        let text = "```sql\nPRAGMA table_info(users)\n```"
+        #expect(throws: SQLParsingError.dangerousOperation("PRAGMA")) {
+            try unrestrictedParser.parse(text)
+        }
+    }
+
+    @Test("Does not match dangerous keywords inside identifiers")
+    func noFalsePositiveOnSubstring() throws {
+        // "DROPDOWN" contains "DROP" as substring but is not the keyword
+        let text = "SELECT dropdown_value FROM settings"
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql.contains("dropdown_value"))
+    }
+
+    // MARK: - Multiple statements
+
+    @Test("Rejects multiple statements separated by semicolons")
+    func rejectMultipleStatements() {
+        let text = "```sql\nSELECT * FROM users; SELECT * FROM orders\n```"
+        #expect(throws: SQLParsingError.multipleStatements) {
+            try readOnlyParser.parse(text)
+        }
+    }
+
+    @Test("Allows semicolons inside string literals")
+    func allowSemicolonInString() throws {
+        let text = "SELECT * FROM users WHERE bio = 'hello; world'"
+        let result = try readOnlyParser.parse(text)
+        #expect(result.sql.contains("hello; world"))
+    }
+
+    // MARK: - ParsedSQL equality
+
+    @Test("ParsedSQL equality works")
+    func parsedSQLEquality() {
+        let a = ParsedSQL(sql: "SELECT 1", operation: .select)
+        let b = ParsedSQL(sql: "SELECT 1", operation: .select)
+        #expect(a == b)
+    }
+
+    // MARK: - Error descriptions
+
+    @Test("Error descriptions are meaningful")
+    func errorDescriptions() {
+        #expect(SQLParsingError.noSQLFound.description.contains("No SQL"))
+        #expect(SQLParsingError.operationNotAllowed(.insert).description.contains("INSERT"))
+        #expect(SQLParsingError.dangerousOperation("DROP").description.contains("DROP"))
+        #expect(SQLParsingError.multipleStatements.description.contains("single"))
+    }
+
+    // MARK: - MutationPolicy integration
+
+    @Test("MutationPolicy allows INSERT on permitted table")
+    func mutationPolicyAllowsInsertOnPermittedTable() throws {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update],
+            allowedTables: ["orders", "order_items"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nINSERT INTO orders (product, qty) VALUES ('Widget', 3)\n```"
+        let result = try parser.parse(text)
+        #expect(result.operation == .insert)
+        #expect(result.requiresConfirmation == false)
+    }
+
+    @Test("MutationPolicy rejects INSERT on non-permitted table")
+    func mutationPolicyRejectsInsertOnForbiddenTable() {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update],
+            allowedTables: ["orders"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nINSERT INTO users (name) VALUES ('Alice')\n```"
+        #expect(throws: SQLParsingError.tableNotAllowed(table: "users", operation: .insert)) {
+            try parser.parse(text)
+        }
+    }
+
+    @Test("MutationPolicy rejects UPDATE on non-permitted table")
+    func mutationPolicyRejectsUpdateOnForbiddenTable() {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update],
+            allowedTables: ["orders"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nUPDATE users SET name = 'Bob' WHERE id = 1\n```"
+        #expect(throws: SQLParsingError.tableNotAllowed(table: "users", operation: .update)) {
+            try parser.parse(text)
+        }
+    }
+
+    @Test("MutationPolicy rejects DELETE on non-permitted table")
+    func mutationPolicyRejectsDeleteOnForbiddenTable() {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update, .delete],
+            allowedTables: ["temp_data"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nDELETE FROM users WHERE id = 99\n```"
+        #expect(throws: SQLParsingError.tableNotAllowed(table: "users", operation: .delete)) {
+            try parser.parse(text)
+        }
+    }
+
+    @Test("MutationPolicy allows mutation on any table when allowedTables is nil")
+    func mutationPolicyAllowsAllTablesWhenNil() throws {
+        let policy = MutationPolicy(allowedOperations: [.insert, .update])
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nINSERT INTO any_table (col) VALUES ('val')\n```"
+        let result = try parser.parse(text)
+        #expect(result.operation == .insert)
+    }
+
+    @Test("MutationPolicy SELECT is never restricted by table allowlist")
+    func mutationPolicySelectIgnoresTableRestrictions() throws {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert],
+            allowedTables: ["orders"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        // SELECT from a table NOT in allowedTables — should still work
+        let text = "```sql\nSELECT * FROM users\n```"
+        let result = try parser.parse(text)
+        #expect(result.operation == .select)
+        #expect(result.requiresConfirmation == false)
+    }
+
+    @Test("MutationPolicy DELETE requires confirmation by default")
+    func mutationPolicyDeleteRequiresConfirmation() throws {
+        let policy = MutationPolicy(allowedOperations: [.delete])
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nDELETE FROM users WHERE id = 1\n```"
+        let result = try parser.parse(text)
+        #expect(result.operation == .delete)
+        #expect(result.requiresConfirmation == true)
+    }
+
+    @Test("MutationPolicy DELETE skips confirmation when configured")
+    func mutationPolicyDeleteNoConfirmation() throws {
+        let policy = MutationPolicy(
+            allowedOperations: [.delete],
+            requiresDestructiveConfirmation: false
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "```sql\nDELETE FROM users WHERE id = 1\n```"
+        let result = try parser.parse(text)
+        #expect(result.operation == .delete)
+        #expect(result.requiresConfirmation == false)
+    }
+
+    @Test("MutationPolicy readOnly preset rejects all mutations")
+    func mutationPolicyReadOnlyRejectsAll() {
+        let parser = SQLQueryParser(mutationPolicy: .readOnly)
+        #expect(throws: SQLParsingError.operationNotAllowed(.insert)) {
+            try parser.parse("INSERT INTO t (a) VALUES (1)")
+        }
+        #expect(throws: SQLParsingError.operationNotAllowed(.update)) {
+            try parser.parse("UPDATE t SET a = 1")
+        }
+        #expect(throws: SQLParsingError.operationNotAllowed(.delete)) {
+            try parser.parse("DELETE FROM t WHERE id = 1")
+        }
+    }
+
+    @Test("MutationPolicy table matching is case-insensitive")
+    func mutationPolicyTableCaseInsensitive() throws {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert],
+            allowedTables: ["Orders"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+        let text = "INSERT INTO orders (product) VALUES ('Widget')"
+        let result = try parser.parse(text)
+        #expect(result.operation == .insert)
+    }
+
+    @Test("MutationPolicy handles quoted table names")
+    func mutationPolicyQuotedTableNames() throws {
+        let policy = MutationPolicy(
+            allowedOperations: [.insert, .update],
+            allowedTables: ["order_items"]
+        )
+        let parser = SQLQueryParser(mutationPolicy: policy)
+
+        // Backtick-quoted
+        let backtick = "INSERT INTO `order_items` (qty) VALUES (5)"
+        let r1 = try parser.parse(backtick)
+        #expect(r1.operation == .insert)
+
+        // Double-quote-quoted
+        let doubleQuote = "UPDATE \"order_items\" SET qty = 10 WHERE id = 1"
+        let r2 = try parser.parse(doubleQuote)
+        #expect(r2.operation == .update)
+    }
+
+    @Test("Error description for tableNotAllowed is meaningful")
+    func tableNotAllowedDescription() {
+        let error = SQLParsingError.tableNotAllowed(table: "secret", operation: .delete)
+        #expect(error.description.contains("secret"))
+        #expect(error.description.contains("DELETE"))
+    }
+
+    @Test("Error description for confirmationRequired is meaningful")
+    func confirmationRequiredDescription() {
+        let error = SQLParsingError.confirmationRequired(sql: "DELETE FROM x", operation: .delete)
+        #expect(error.description.contains("DELETE"))
+        #expect(error.description.contains("confirmation"))
+    }
+}

Tests/SwiftDBAITests/SchemaIntrospectorTests.swift

@@ -0,0 +1,234 @@
+// SchemaIntrospectorTests.swift
+// SwiftDBAI
+
+import Testing
+import GRDB
+@testable import SwiftDBAI
+
+@Suite("SchemaIntrospector")
+struct SchemaIntrospectorTests {
+
+    // MARK: - Helper
+
+    /// Creates an in-memory database with a sample schema for testing.
+    private func makeTestDatabase() throws -> DatabaseQueue {
+        let db = try DatabaseQueue(configuration: {
+            var config = Configuration()
+            config.foreignKeysEnabled = true
+            return config
+        }())
+
+        try db.write { db in
+            try db.execute(sql: """
+                CREATE TABLE authors (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    name TEXT NOT NULL,
+                    email TEXT UNIQUE
+                );
+                """)
+
+            try db.execute(sql: """
+                CREATE TABLE books (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    title TEXT NOT NULL,
+                    author_id INTEGER NOT NULL REFERENCES authors(id) ON DELETE CASCADE,
+                    published_date TEXT,
+                    price REAL DEFAULT 9.99
+                );
+                """)
+
+            try db.execute(sql: """
+                CREATE INDEX idx_books_author ON books(author_id);
+                """)
+
+            try db.execute(sql: """
+                CREATE INDEX idx_books_title ON books(title);
+                """)
+
+            try db.execute(sql: """
+                CREATE TABLE reviews (
+                    id INTEGER PRIMARY KEY,
+                    book_id INTEGER NOT NULL REFERENCES books(id),
+                    rating INTEGER NOT NULL,
+                    comment TEXT
+                );
+                """)
+        }
+
+        return db
+    }
+
+    // MARK: - Tests
+
+    @Test("Discovers all user tables")
+    func discoversAllTables() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        #expect(schema.tableNames.count == 3)
+        #expect(schema.tableNames.contains("authors"))
+        #expect(schema.tableNames.contains("books"))
+        #expect(schema.tableNames.contains("reviews"))
+    }
+
+    @Test("Excludes sqlite_ internal tables")
+    func excludesInternalTables() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        for name in schema.tableNames {
+            #expect(!name.hasPrefix("sqlite_"))
+        }
+    }
+
+    @Test("Introspects column names and types")
+    func introspectsColumns() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        let books = try #require(schema.tables["books"])
+        #expect(books.columns.count == 5)
+
+        let titleCol = try #require(books.columns.first { $0.name == "title" })
+        #expect(titleCol.type == "TEXT")
+        #expect(titleCol.isNotNull == true)
+        #expect(titleCol.isPrimaryKey == false)
+
+        let priceCol = try #require(books.columns.first { $0.name == "price" })
+        #expect(priceCol.type == "REAL")
+        #expect(priceCol.defaultValue == "9.99")
+    }
+
+    @Test("Detects primary keys")
+    func detectsPrimaryKeys() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        let authors = try #require(schema.tables["authors"])
+        #expect(authors.primaryKey == ["id"])
+
+        let idCol = try #require(authors.columns.first { $0.name == "id" })
+        #expect(idCol.isPrimaryKey == true)
+    }
+
+    @Test("Detects foreign keys")
+    func detectsForeignKeys() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        let books = try #require(schema.tables["books"])
+        #expect(books.foreignKeys.count == 1)
+
+        let fk = books.foreignKeys[0]
+        #expect(fk.fromColumn == "author_id")
+        #expect(fk.toTable == "authors")
+        #expect(fk.toColumn == "id")
+        #expect(fk.onDelete == "CASCADE")
+    }
+
+    @Test("Detects indexes")
+    func detectsIndexes() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        let books = try #require(schema.tables["books"])
+        let indexNames = books.indexes.map(\.name)
+        #expect(indexNames.contains("idx_books_author"))
+        #expect(indexNames.contains("idx_books_title"))
+    }
+
+    @Test("Detects NOT NULL constraints")
+    func detectsNotNull() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        let reviews = try #require(schema.tables["reviews"])
+        let ratingCol = try #require(reviews.columns.first { $0.name == "rating" })
+        #expect(ratingCol.isNotNull == true)
+
+        let commentCol = try #require(reviews.columns.first { $0.name == "comment" })
+        #expect(commentCol.isNotNull == false)
+    }
+
+    @Test("Generates LLM-friendly schema description")
+    func generatesSchemaDescription() async throws {
+        let db = try makeTestDatabase()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        let description = schema.schemaDescription
+        #expect(description.contains("TABLE authors"))
+        #expect(description.contains("TABLE books"))
+        #expect(description.contains("FOREIGN KEY"))
+        #expect(description.contains("REFERENCES authors(id)"))
+        #expect(description.contains("INDEX idx_books_author"))
+    }
+
+    @Test("Handles empty database")
+    func handlesEmptyDatabase() async throws {
+        let db = try DatabaseQueue()
+        let schema = try await SchemaIntrospector.introspect(database: db)
+
+        #expect(schema.tables.isEmpty)
+        #expect(schema.tableNames.isEmpty)
+        #expect(schema.schemaDescription.isEmpty)
+    }
+
+    @Test("Handles composite primary keys")
+    func handlesCompositePrimaryKey() async throws {
+        let db = try DatabaseQueue()
+        try await db.write { db in
+            try db.execute(sql: """
+                CREATE TABLE book_tags (
+                    book_id INTEGER NOT NULL,
+                    tag_id INTEGER NOT NULL,
+                    PRIMARY KEY (book_id, tag_id)
+                );
+                """)
+        }
+
+        let schema = try await SchemaIntrospector.introspect(database: db)
+        let bookTags = try #require(schema.tables["book_tags"])
+        #expect(bookTags.primaryKey.count == 2)
+        #expect(bookTags.primaryKey.contains("book_id"))
+        #expect(bookTags.primaryKey.contains("tag_id"))
+    }
+
+    @Test("Handles tables with no explicit types (SQLite dynamic typing)")
+    func handlesDynamicTyping() async throws {
+        let db = try DatabaseQueue()
+        try await db.write { db in
+            try db.execute(sql: """
+                CREATE TABLE flexible (
+                    id INTEGER PRIMARY KEY,
+                    data,
+                    info BLOB
+                );
+                """)
+        }
+
+        let schema = try await SchemaIntrospector.introspect(database: db)
+        let flexible = try #require(schema.tables["flexible"])
+
+        let dataCol = try #require(flexible.columns.first { $0.name == "data" })
+        #expect(dataCol.type == "") // No declared type
+
+        let infoCol = try #require(flexible.columns.first { $0.name == "info" })
+        #expect(infoCol.type == "BLOB")
+    }
+
+    @Test("Synchronous introspection works within database access")
+    func synchronousIntrospection() async throws {
+        let db = try DatabaseQueue()
+        try await db.write { db in
+            try db.execute(sql: "CREATE TABLE test (id INTEGER PRIMARY KEY, val TEXT);")
+        }
+
+        let schema = try await db.read { db in
+            try SchemaIntrospector.introspect(db: db)
+        }
+
+        #expect(schema.tableNames == ["test"])
+        let table = try #require(schema.tables["test"])
+        #expect(table.columns.count == 2)
+    }
+}

Tests/SwiftDBAITests/ScrollableDataTableViewTests.swift

@@ -0,0 +1,133 @@
+// ScrollableDataTableViewTests.swift
+// SwiftDBAITests
+//
+// Tests for the ScrollableDataTableView component.
+
+import Foundation
+import Testing
+@testable import SwiftDBAI
+
+@Suite("ScrollableDataTableView")
+@MainActor
+struct ScrollableDataTableViewTests {
+
+    // MARK: - Test Helpers
+
+    private func makeDataTable(
+        columnNames: [String] = ["id", "name", "score"],
+        inferredTypes: [DataTable.InferredType] = [.integer, .text, .real],
+        rowCount: Int = 5
+    ) -> DataTable {
+        let columns = columnNames.enumerated().map { idx, name in
+            DataTable.Column(name: name, index: idx, inferredType: inferredTypes[idx])
+        }
+        let rows = (0..<rowCount).map { i in
+            DataTable.Row(
+                id: i,
+                values: [
+                    .integer(Int64(i + 1)),
+                    .text("Item \(i + 1)"),
+                    .real(Double(i) * 10.5),
+                ],
+                columnNames: columnNames
+            )
+        }
+        return DataTable(columns: columns, rows: rows, sql: "SELECT * FROM test", executionTime: 0.015)
+    }
+
+    private func makeEmptyDataTable() -> DataTable {
+        DataTable(columns: [], rows: [], sql: "", executionTime: 0)
+    }
+
+    // MARK: - Initialization Tests
+
+    @Test("Initializes with default parameters")
+    func initWithDefaults() {
+        let table = makeDataTable()
+        let view = ScrollableDataTableView(dataTable: table)
+
+        #expect(view.minimumColumnWidth == 80)
+        #expect(view.maximumColumnWidth == 250)
+        #expect(view.showAlternatingRows == true)
+        #expect(view.showFooter == true)
+    }
+
+    @Test("Initializes with custom parameters")
+    func initWithCustomParams() {
+        let table = makeDataTable()
+        let view = ScrollableDataTableView(
+            dataTable: table,
+            minimumColumnWidth: 100,
+            maximumColumnWidth: 300,
+            showAlternatingRows: false,
+            showFooter: false
+        )
+
+        #expect(view.minimumColumnWidth == 100)
+        #expect(view.maximumColumnWidth == 300)
+        #expect(view.showAlternatingRows == false)
+        #expect(view.showFooter == false)
+    }
+
+    @Test("Handles empty data table")
+    func handlesEmptyTable() {
+        let table = makeEmptyDataTable()
+        let view = ScrollableDataTableView(dataTable: table)
+        #expect(view.dataTable.isEmpty)
+    }
+
+    @Test("Handles single row table")
+    func handlesSingleRow() {
+        let table = makeDataTable(rowCount: 1)
+        let view = ScrollableDataTableView(dataTable: table)
+        #expect(view.dataTable.rowCount == 1)
+        #expect(view.dataTable.columnCount == 3)
+    }
+
+    @Test("Handles single column table")
+    func handlesSingleColumn() {
+        let columns = [DataTable.Column(name: "count", index: 0, inferredType: .integer)]
+        let rows = [
+            DataTable.Row(id: 0, values: [.integer(42)], columnNames: ["count"])
+        ]
+        let table = DataTable(columns: columns, rows: rows, sql: "SELECT count(*) FROM t", executionTime: 0.001)
+        let view = ScrollableDataTableView(dataTable: table)
+        #expect(view.dataTable.columnCount == 1)
+        #expect(view.dataTable.rowCount == 1)
+    }
+
+    @Test("Handles large number of rows")
+    func handlesLargeRowCount() {
+        let table = makeDataTable(rowCount: 1000)
+        let view = ScrollableDataTableView(dataTable: table)
+        #expect(view.dataTable.rowCount == 1000)
+    }
+
+    @Test("Handles null values in cells")
+    func handlesNullValues() {
+        let columns = [
+            DataTable.Column(name: "name", index: 0, inferredType: .text),
+            DataTable.Column(name: "value", index: 1, inferredType: .null),
+        ]
+        let rows = [
+            DataTable.Row(id: 0, values: [.text("test"), .null], columnNames: ["name", "value"])
+        ]
+        let table = DataTable(columns: columns, rows: rows)
+        let view = ScrollableDataTableView(dataTable: table)
+        #expect(view.dataTable.rows[0][1] == .null)
+    }
+
+    @Test("Handles blob values in cells")
+    func handlesBlobValues() {
+        let columns = [
+            DataTable.Column(name: "data", index: 0, inferredType: .blob),
+        ]
+        let blobData = Data([0x00, 0xFF, 0xAB])
+        let rows = [
+            DataTable.Row(id: 0, values: [.blob(blobData)], columnNames: ["data"])
+        ]
+        let table = DataTable(columns: columns, rows: rows)
+        let view = ScrollableDataTableView(dataTable: table)
+        #expect(view.dataTable.rows[0][0] == QueryResult.Value.blob(blobData))
+    }
+}

Tests/SwiftDBAITests/TextSummaryRendererTests.swift

@@ -0,0 +1,301 @@
+// TextSummaryRendererTests.swift
+// SwiftDBAI
+
+import AnyLanguageModel
+import Testing
+import Foundation
+@testable import SwiftDBAI
+
+@Suite("TextSummaryRenderer")
+struct TextSummaryRendererTests {
+
+    // MARK: - QueryResult.Value Tests
+
+    @Test("Value description renders correctly")
+    func valueDescriptions() {
+        #expect(QueryResult.Value.text("hello").description == "hello")
+        #expect(QueryResult.Value.integer(42).description == "42")
+        #expect(QueryResult.Value.real(3.14).description == "3.14")
+        #expect(QueryResult.Value.null.description == "NULL")
+        #expect(QueryResult.Value.blob(Data([0x01, 0x02])).description == "<2 bytes>")
+    }
+
+    @Test("Value doubleValue extracts numeric values")
+    func valueDoubleValues() {
+        #expect(QueryResult.Value.integer(42).doubleValue == 42.0)
+        #expect(QueryResult.Value.real(3.14).doubleValue == 3.14)
+        #expect(QueryResult.Value.text("100").doubleValue == 100.0)
+        #expect(QueryResult.Value.text("not a number").doubleValue == nil)
+        #expect(QueryResult.Value.null.doubleValue == nil)
+        #expect(QueryResult.Value.blob(Data()).doubleValue == nil)
+    }
+
+    @Test("Value isNull works correctly")
+    func valueIsNull() {
+        #expect(QueryResult.Value.null.isNull == true)
+        #expect(QueryResult.Value.text("").isNull == false)
+        #expect(QueryResult.Value.integer(0).isNull == false)
+    }
+
+    // MARK: - QueryResult Tests
+
+    @Test("Empty result has correct properties")
+    func emptyResult() {
+        let result = QueryResult(
+            columns: ["id", "name"],
+            rows: [],
+            sql: "SELECT id, name FROM users",
+            executionTime: 0.01
+        )
+        #expect(result.rowCount == 0)
+        #expect(result.isAggregate == false)
+        #expect(result.tabularDescription == "(empty result set)")
+    }
+
+    @Test("Single aggregate result is detected")
+    func aggregateDetection() {
+        let result = QueryResult(
+            columns: ["COUNT(*)"],
+            rows: [["COUNT(*)": .integer(42)]],
+            sql: "SELECT COUNT(*) FROM users",
+            executionTime: 0.01
+        )
+        #expect(result.isAggregate == true)
+    }
+
+    @Test("Multi-row result is not aggregate")
+    func nonAggregateDetection() {
+        let result = QueryResult(
+            columns: ["name"],
+            rows: [
+                ["name": .text("Alice")],
+                ["name": .text("Bob")],
+            ],
+            sql: "SELECT name FROM users",
+            executionTime: 0.01
+        )
+        #expect(result.isAggregate == false)
+    }
+
+    @Test("Tabular description formats correctly")
+    func tabularDescription() {
+        let result = QueryResult(
+            columns: ["id", "name"],
+            rows: [
+                ["id": .integer(1), "name": .text("Alice")],
+                ["id": .integer(2), "name": .text("Bob")],
+            ],
+            sql: "SELECT id, name FROM users",
+            executionTime: 0.01
+        )
+        let desc = result.tabularDescription
+        #expect(desc.contains("id | name"))
+        #expect(desc.contains("1 | Alice"))
+        #expect(desc.contains("2 | Bob"))
+    }
+
+    @Test("values(forColumn:) extracts column values")
+    func valuesForColumn() {
+        let result = QueryResult(
+            columns: ["name"],
+            rows: [
+                ["name": .text("Alice")],
+                ["name": .text("Bob")],
+            ],
+            sql: "SELECT name FROM users",
+            executionTime: 0.01
+        )
+        let values = result.values(forColumn: "name")
+        #expect(values.count == 2)
+        #expect(values[0] == .text("Alice"))
+    }
+
+    // MARK: - Local Summary Tests (no LLM required)
+
+    @Test("Local summary for empty result")
+    func localSummaryEmpty() {
+        let result = makeResult(columns: ["id"], rows: [])
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "Any users?")
+        #expect(summary == "No results found for your query.")
+    }
+
+    @Test("Local summary for single aggregate")
+    func localSummarySingleAggregate() {
+        let result = makeResult(
+            columns: ["COUNT(*)"],
+            rows: [["COUNT(*)": .integer(42)]]
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "How many?")
+        #expect(summary.contains("42"))
+    }
+
+    @Test("Local summary for multiple aggregates")
+    func localSummaryMultipleAggregates() {
+        let result = makeResult(
+            columns: ["COUNT(*)", "AVG(price)"],
+            rows: [["COUNT(*)": .integer(10), "AVG(price)": .real(25.5)]]
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "Stats?")
+        #expect(summary.contains("count"))
+        #expect(summary.contains("average price"))
+    }
+
+    @Test("Local summary for single record")
+    func localSummarySingleRecord() {
+        let result = makeResult(
+            columns: ["name", "email"],
+            rows: [["name": .text("Alice"), "email": .text("alice@example.com")]]
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "Who?")
+        #expect(summary.contains("1 result"))
+        #expect(summary.contains("Alice"))
+    }
+
+    @Test("Local summary for multiple records with name column")
+    func localSummaryMultipleWithNames() {
+        let result = makeResult(
+            columns: ["name", "age"],
+            rows: [
+                ["name": .text("Alice"), "age": .integer(30)],
+                ["name": .text("Bob"), "age": .integer(25)],
+                ["name": .text("Charlie"), "age": .integer(35)],
+                ["name": .text("Diana"), "age": .integer(28)],
+            ]
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "List users")
+        #expect(summary.contains("4 results"))
+        #expect(summary.contains("Alice"))
+        #expect(summary.contains("1 more"))
+    }
+
+    @Test("Local summary for mutation result")
+    func localSummaryMutation() {
+        let result = QueryResult(
+            columns: [],
+            rows: [],
+            sql: "INSERT INTO users (name) VALUES ('Test')",
+            executionTime: 0.01,
+            rowsAffected: 1
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "Add user")
+        #expect(summary == "Successfully inserted 1 row.")
+    }
+
+    @Test("Local summary for delete mutation")
+    func localSummaryDelete() {
+        let result = QueryResult(
+            columns: [],
+            rows: [],
+            sql: "DELETE FROM users WHERE id = 5",
+            executionTime: 0.01,
+            rowsAffected: 3
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "Delete old users")
+        #expect(summary == "Successfully deleted 3 rows.")
+    }
+
+    @Test("Local summary for update mutation")
+    func localSummaryUpdate() {
+        let result = QueryResult(
+            columns: [],
+            rows: [],
+            sql: "UPDATE users SET active = 0 WHERE id = 1",
+            executionTime: 0.01,
+            rowsAffected: 1
+        )
+        let renderer = makeMockRenderer()
+        let summary = renderer.localSummary(result: result, userQuestion: "Deactivate user")
+        #expect(summary == "Successfully updated 1 row.")
+    }
+
+    // MARK: - LLM-based Summary Tests (using MockLanguageModel)
+
+    @Test("Summarize with LLM returns mock response for multi-row results")
+    func summarizeWithLLM() async throws {
+        let result = makeResult(
+            columns: ["name", "age"],
+            rows: [
+                ["name": .text("Alice"), "age": .integer(30)],
+                ["name": .text("Bob"), "age": .integer(25)],
+            ]
+        )
+        let mockModel = MockLanguageModel(responseText: "There are 2 users: Alice (30) and Bob (25).")
+        let renderer = TextSummaryRenderer(model: mockModel)
+        let summary = try await renderer.summarize(result: result, userQuestion: "List all users")
+        #expect(summary == "There are 2 users: Alice (30) and Bob (25).")
+    }
+
+    @Test("Summarize returns empty result message without calling LLM")
+    func summarizeEmptyResult() async throws {
+        let result = makeResult(columns: ["id"], rows: [])
+        let renderer = makeMockRenderer()
+        let summary = try await renderer.summarize(result: result, userQuestion: "Find users")
+        #expect(summary == "No results found for your query.")
+    }
+
+    @Test("Summarize returns direct aggregate without calling LLM")
+    func summarizeAggregate() async throws {
+        let result = makeResult(
+            columns: ["COUNT(*)"],
+            rows: [["COUNT(*)": .integer(42)]]
+        )
+        let renderer = makeMockRenderer()
+        let summary = try await renderer.summarize(result: result, userQuestion: "How many?")
+        #expect(summary.contains("42"))
+    }
+
+    @Test("Summarize mutation returns template without calling LLM")
+    func summarizeMutation() async throws {
+        let result = QueryResult(
+            columns: [],
+            rows: [],
+            sql: "UPDATE users SET name = 'Test' WHERE id = 1",
+            executionTime: 0.01,
+            rowsAffected: 1
+        )
+        let renderer = makeMockRenderer()
+        let summary = try await renderer.summarize(result: result, userQuestion: "Update user")
+        #expect(summary == "Successfully updated 1 row.")
+    }
+
+    @Test("Summarize passes context to LLM prompt")
+    func summarizeWithContext() async throws {
+        let result = makeResult(
+            columns: ["total"],
+            rows: [
+                ["total": .real(100.0)],
+                ["total": .real(200.0)],
+            ]
+        )
+        let mockModel = MockLanguageModel(responseText: "The totals are 100 and 200.")
+        let renderer = TextSummaryRenderer(model: mockModel)
+        let summary = try await renderer.summarize(
+            result: result,
+            userQuestion: "Show totals",
+            context: "Amounts are in USD"
+        )
+        #expect(summary == "The totals are 100 and 200.")
+    }
+
+    // MARK: - Helpers
+
+    private func makeResult(
+        columns: [String],
+        rows: [[String: QueryResult.Value]],
+        sql: String = "SELECT * FROM test"
+    ) -> QueryResult {
+        QueryResult(columns: columns, rows: rows, sql: sql, executionTime: 0.01)
+    }
+
+    /// Creates a renderer with a mock model (for localSummary tests that don't hit the LLM).
+    private func makeMockRenderer() -> TextSummaryRenderer {
+        TextSummaryRenderer(model: MockLanguageModel())
+    }
+}

Tests/SwiftDBAITests/ToolExecutionDelegateTests.swift

@@ -0,0 +1,246 @@
+// ToolExecutionDelegateTests.swift
+// SwiftDBAITests
+
+import Foundation
+import Testing
+@testable import SwiftDBAI
+
+@Suite("DestructiveClassification")
+struct DestructiveClassificationTests {
+
+    // MARK: - Safe statements
+
+    @Test("SELECT is classified as safe")
+    func selectIsSafe() {
+        let result = classifySQL("SELECT * FROM users")
+        #expect(result == .safe)
+        #expect(!result.requiresConfirmation)
+        #expect(!result.isMutating)
+    }
+
+    @Test("WITH (CTE) is classified as safe")
+    func withIsSafe() {
+        let result = classifySQL("WITH cte AS (SELECT 1) SELECT * FROM cte")
+        #expect(result == .safe)
+    }
+
+    // MARK: - Mutation statements
+
+    @Test("INSERT is classified as mutation")
+    func insertIsMutation() {
+        let result = classifySQL("INSERT INTO users (name) VALUES ('Alice')")
+        #expect(result == .mutation(.insert))
+        #expect(!result.requiresConfirmation)
+        #expect(result.isMutating)
+    }
+
+    @Test("UPDATE is classified as mutation")
+    func updateIsMutation() {
+        let result = classifySQL("UPDATE users SET name = 'Bob' WHERE id = 1")
+        #expect(result == .mutation(.update))
+        #expect(!result.requiresConfirmation)
+        #expect(result.isMutating)
+    }
+
+    // MARK: - Destructive statements
+
+    @Test("DELETE is classified as destructive")
+    func deleteIsDestructive() {
+        let result = classifySQL("DELETE FROM users WHERE id = 1")
+        #expect(result == .destructive(.delete))
+        #expect(result.requiresConfirmation)
+        #expect(result.isMutating)
+    }
+
+    @Test("DROP is classified as destructive")
+    func dropIsDestructive() {
+        let result = classifySQL("DROP TABLE users")
+        #expect(result == .destructive(.drop))
+        #expect(result.requiresConfirmation)
+    }
+
+    @Test("ALTER is classified as destructive")
+    func alterIsDestructive() {
+        let result = classifySQL("ALTER TABLE users ADD COLUMN age INTEGER")
+        #expect(result == .destructive(.alter))
+        #expect(result.requiresConfirmation)
+    }
+
+    @Test("TRUNCATE is classified as destructive")
+    func truncateIsDestructive() {
+        let result = classifySQL("TRUNCATE TABLE users")
+        #expect(result == .destructive(.truncate))
+        #expect(result.requiresConfirmation)
+    }
+
+    // MARK: - Case insensitivity
+
+    @Test("Classification is case-insensitive")
+    func caseInsensitive() {
+        #expect(classifySQL("delete from users") == .destructive(.delete))
+        #expect(classifySQL("Drop Table foo") == .destructive(.drop))
+        #expect(classifySQL("select 1") == .safe)
+        #expect(classifySQL("INSERT into t values (1)") == .mutation(.insert))
+    }
+
+    // MARK: - Leading whitespace
+
+    @Test("Classification ignores leading whitespace")
+    func leadingWhitespace() {
+        #expect(classifySQL("  \n  DELETE FROM users") == .destructive(.delete))
+        #expect(classifySQL("\t SELECT 1") == .safe)
+    }
+
+    // MARK: - SQLStatementKind
+
+    @Test("Destructive kinds are correct")
+    func destructiveKinds() {
+        #expect(SQLStatementKind.delete.isDestructive)
+        #expect(SQLStatementKind.drop.isDestructive)
+        #expect(SQLStatementKind.alter.isDestructive)
+        #expect(SQLStatementKind.truncate.isDestructive)
+        #expect(!SQLStatementKind.select.isDestructive)
+        #expect(!SQLStatementKind.insert.isDestructive)
+        #expect(!SQLStatementKind.update.isDestructive)
+    }
+
+    @Test("Mutation kinds are correct")
+    func mutationKinds() {
+        #expect(SQLStatementKind.insert.isMutation)
+        #expect(SQLStatementKind.update.isMutation)
+        #expect(!SQLStatementKind.select.isMutation)
+        #expect(!SQLStatementKind.delete.isMutation)
+    }
+}
+
+@Suite("ToolExecutionDelegate")
+struct ToolExecutionDelegateProtocolTests {
+
+    @Test("AutoApproveDelegate approves all operations")
+    func autoApprove() async {
+        let delegate = AutoApproveDelegate()
+        let context = DestructiveOperationContext(
+            sql: "DELETE FROM users",
+            statementKind: .delete,
+            classification: .destructive(.delete),
+            description: "Delete all rows from users"
+        )
+        let result = await delegate.confirmDestructiveOperation(context)
+        #expect(result == true)
+    }
+
+    @Test("RejectAllDelegate rejects all operations")
+    func rejectAll() async {
+        let delegate = RejectAllDelegate()
+        let context = DestructiveOperationContext(
+            sql: "DROP TABLE users",
+            statementKind: .drop,
+            classification: .destructive(.drop),
+            description: "Drop the users table"
+        )
+        let result = await delegate.confirmDestructiveOperation(context)
+        #expect(result == false)
+    }
+
+    @Test("Default delegate implementation rejects destructive operations")
+    func defaultRejects() async {
+        struct EmptyDelegate: ToolExecutionDelegate {}
+        let delegate = EmptyDelegate()
+        let context = DestructiveOperationContext(
+            sql: "DELETE FROM users",
+            statementKind: .delete,
+            classification: .destructive(.delete),
+            description: "Delete rows"
+        )
+        let result = await delegate.confirmDestructiveOperation(context)
+        #expect(result == false)
+    }
+}
+
+// MARK: - Tracking Delegate for Integration Tests
+
+/// A delegate that records all calls for verification in tests.
+private final class TrackingDelegate: ToolExecutionDelegate, @unchecked Sendable {
+    private let lock = NSLock()
+
+    private var _confirmCalls: [DestructiveOperationContext] = []
+    private var _willExecuteCalls: [(sql: String, classification: DestructiveClassification)] = []
+    private var _didExecuteCalls: [(sql: String, success: Bool)] = []
+    private var _confirmResult: Bool
+
+    var confirmCalls: [DestructiveOperationContext] {
+        lock.withLock { _confirmCalls }
+    }
+
+    var willExecuteCalls: [(sql: String, classification: DestructiveClassification)] {
+        lock.withLock { _willExecuteCalls }
+    }
+
+    var didExecuteCalls: [(sql: String, success: Bool)] {
+        lock.withLock { _didExecuteCalls }
+    }
+
+    init(confirmResult: Bool) {
+        self._confirmResult = confirmResult
+    }
+
+    func confirmDestructiveOperation(_ context: DestructiveOperationContext) async -> Bool {
+        lock.withLock { _confirmCalls.append(context) }
+        return _confirmResult
+    }
+
+    func willExecuteSQL(_ sql: String, classification: DestructiveClassification) async {
+        lock.withLock { _willExecuteCalls.append((sql: sql, classification: classification)) }
+    }
+
+    func didExecuteSQL(_ sql: String, success: Bool) async {
+        lock.withLock { _didExecuteCalls.append((sql: sql, success: success)) }
+    }
+}
+
+@Suite("ToolExecutionDelegate - ChatEngine Integration")
+struct DelegateIntegrationTests {
+
+    @Test("DestructiveOperationContext captures target table")
+    func contextCapturesTable() {
+        let context = DestructiveOperationContext(
+            sql: "DELETE FROM users WHERE id = 1",
+            statementKind: .delete,
+            classification: .destructive(.delete),
+            description: "Delete from users",
+            targetTable: "users"
+        )
+        #expect(context.targetTable == "users")
+        #expect(context.statementKind == .delete)
+        #expect(context.classification.requiresConfirmation)
+    }
+
+    @Test("classifySQL returns destructive for DELETE")
+    func classifySQLDestructive() {
+        let result = classifySQL("DELETE FROM orders WHERE id = 5")
+        #expect(result == .destructive(.delete))
+        #expect(result.requiresConfirmation)
+    }
+
+    @Test("classifySQL returns safe for SELECT")
+    func classifySQLSafe() {
+        let result = classifySQL("SELECT * FROM users")
+        #expect(result == .safe)
+        #expect(!result.requiresConfirmation)
+    }
+
+    @Test("classifySQL returns mutation for INSERT")
+    func classifySQLMutation() {
+        let result = classifySQL("INSERT INTO users (name) VALUES ('test')")
+        #expect(result == .mutation(.insert))
+        #expect(!result.requiresConfirmation)
+    }
+
+    @Test("DestructiveClassification.isMutating is true for mutations and destructive")
+    func isMutatingCovers() {
+        #expect(DestructiveClassification.mutation(.insert).isMutating)
+        #expect(DestructiveClassification.mutation(.update).isMutating)
+        #expect(DestructiveClassification.destructive(.delete).isMutating)
+        #expect(!DestructiveClassification.safe.isMutating)
+    }
+}

Tests/SwiftDBAITests/UnifiedProviderTestHarness.swift

@@ -0,0 +1,617 @@
+// UnifiedProviderTestHarness.swift
+// SwiftDBAI Tests
+//
+// A unified test harness that validates all seven provider types
+// conform to the AnyLanguageModel protocol and produce consistent
+// ChatEngine-compatible output. Covers: OpenAI, Anthropic, Gemini,
+// OpenAI-Compatible, Ollama, llama.cpp, and on-device (MLX/CoreML).
+
+import AnyLanguageModel
+import Foundation
+import GRDB
+import Testing
+
+@testable import SwiftDBAI
+
+// MARK: - Provider-Simulating Mock Models
+
+/// A mock that records which LanguageModel protocol methods were called,
+/// the arguments passed, and returns configurable responses.
+/// Used to validate that every provider path through ChatEngine
+/// exercises the same protocol surface.
+final class ProviderConformanceMock: LanguageModel, @unchecked Sendable {
+    typealias UnavailableReason = Never
+
+    /// Track calls to verify protocol conformance exercised fully.
+    struct CallRecord: Sendable {
+        let method: String
+        let promptDescription: String
+        let timestamp: Date
+    }
+
+    private let lock = NSLock()
+    private var _calls: [CallRecord] = []
+    private let _responses: [String]
+    private var _callIndex = 0
+
+    /// Label for diagnostics.
+    let providerName: String
+
+    var calls: [CallRecord] {
+        lock.lock()
+        defer { lock.unlock() }
+        return _calls
+    }
+
+    init(providerName: String, responses: [String]) {
+        self.providerName = providerName
+        self._responses = responses
+    }
+
+    private func nextResponse() -> String {
+        lock.lock()
+        defer { lock.unlock() }
+        let idx = _callIndex
+        _callIndex += 1
+        return idx < _responses.count ? _responses[idx] : "fallback response"
+    }
+
+    private func recordCall(method: String, prompt: String) {
+        lock.lock()
+        _calls.append(CallRecord(method: method, promptDescription: prompt, timestamp: Date()))
+        lock.unlock()
+    }
+
+    func respond<Content>(
+        within session: LanguageModelSession,
+        to prompt: Prompt,
+        generating type: Content.Type,
+        includeSchemaInPrompt: Bool,
+        options: GenerationOptions
+    ) async throws -> LanguageModelSession.Response<Content> where Content: Generable {
+        recordCall(method: "respond", prompt: prompt.description)
+        let text = nextResponse()
+        let rawContent = GeneratedContent(kind: .string(text))
+        let content = try Content(rawContent)
+        return LanguageModelSession.Response(
+            content: content,
+            rawContent: rawContent,
+            transcriptEntries: [][...]
+        )
+    }
+
+    func streamResponse<Content>(
+        within session: LanguageModelSession,
+        to prompt: Prompt,
+        generating type: Content.Type,
+        includeSchemaInPrompt: Bool,
+        options: GenerationOptions
+    ) -> sending LanguageModelSession.ResponseStream<Content> where Content: Generable {
+        recordCall(method: "streamResponse", prompt: prompt.description)
+        let text = nextResponse()
+        let rawContent = GeneratedContent(kind: .string(text))
+        let content = try! Content(rawContent)
+        return LanguageModelSession.ResponseStream(content: content, rawContent: rawContent)
+    }
+}
+
+// MARK: - Test Database Helper
+
+/// Creates a minimal in-memory database for provider integration tests.
+private func makeProviderTestDatabase() throws -> DatabaseQueue {
+    let db = try DatabaseQueue(path: ":memory:")
+    try db.write { db in
+        try db.execute(sql: """
+            CREATE TABLE products (
+                id INTEGER PRIMARY KEY,
+                name TEXT NOT NULL,
+                price REAL NOT NULL,
+                category TEXT NOT NULL
+            )
+            """)
+        try db.execute(sql: """
+            INSERT INTO products (name, price, category) VALUES
+            ('Widget', 9.99, 'tools'),
+            ('Gadget', 24.99, 'electronics'),
+            ('Doohickey', 4.50, 'tools')
+            """)
+    }
+    return db
+}
+
+// MARK: - Unified Provider Test Harness
+
+@Suite("Unified Provider Test Harness")
+struct UnifiedProviderTestHarness {
+
+    // MARK: - Provider Configuration Enumeration
+
+    /// All seven provider types that SwiftDBAI supports.
+    enum TestedProvider: String, CaseIterable {
+        case openAI
+        case anthropic
+        case gemini
+        case openAICompatible
+        case ollama
+        case llamaCpp
+        case onDevice
+    }
+
+    /// Creates a ProviderConformanceMock simulating each provider type.
+    private func makeMock(for provider: TestedProvider, responses: [String]) -> ProviderConformanceMock {
+        ProviderConformanceMock(providerName: provider.rawValue, responses: responses)
+    }
+
+    // MARK: - 1. Protocol Conformance — All Providers Are LanguageModel
+
+    @Test("All provider types produce instances conforming to LanguageModel protocol")
+    func allProvidersConformToLanguageModel() {
+        // Cloud providers via ProviderConfiguration.makeModel()
+        let openAI = ProviderConfiguration.openAI(apiKey: "test-key", model: "gpt-4o").makeModel()
+        let anthropic = ProviderConfiguration.anthropic(apiKey: "test-key", model: "claude-sonnet-4-20250514").makeModel()
+        let gemini = ProviderConfiguration.gemini(apiKey: "test-key", model: "gemini-2.0-flash").makeModel()
+        let openAICompatible = ProviderConfiguration.openAICompatible(
+            apiKey: "test-key",
+            model: "local-model",
+            baseURL: URL(string: "http://localhost:8080/v1/")!
+        ).makeModel()
+        let ollama = ProviderConfiguration.ollama(model: "llama3.2").makeModel()
+        let llamaCpp = ProviderConfiguration.llamaCpp(model: "default").makeModel()
+        // On-device MLX (wraps as openAICompatible internally)
+        let onDeviceMLX = ProviderConfiguration.onDeviceMLX(
+            MLXProviderConfiguration(modelId: "test-model")
+        ).makeModel()
+
+        // Verify all are LanguageModel
+        let models: [(String, any LanguageModel)] = [
+            ("OpenAI", openAI),
+            ("Anthropic", anthropic),
+            ("Gemini", gemini),
+            ("OpenAI-Compatible", openAICompatible),
+            ("Ollama", ollama),
+            ("llama.cpp", llamaCpp),
+            ("On-Device MLX", onDeviceMLX),
+        ]
+
+        for (name, model) in models {
+            // Protocol conformance is compile-time, but we verify isAvailable works
+            #expect(model.isAvailable, "\(name) model should report as available")
+        }
+    }
+
+    @Test("All provider configurations produce correct concrete model types")
+    func providerConfigurationsProduceCorrectTypes() {
+        let openAI = ProviderConfiguration.openAI(apiKey: "k", model: "m").makeModel()
+        #expect(openAI is OpenAILanguageModel, "OpenAI config should produce OpenAILanguageModel")
+
+        let anthropic = ProviderConfiguration.anthropic(apiKey: "k", model: "m").makeModel()
+        #expect(anthropic is AnthropicLanguageModel, "Anthropic config should produce AnthropicLanguageModel")
+
+        let gemini = ProviderConfiguration.gemini(apiKey: "k", model: "m").makeModel()
+        #expect(gemini is GeminiLanguageModel, "Gemini config should produce GeminiLanguageModel")
+
+        let openAICompat = ProviderConfiguration.openAICompatible(
+            apiKey: "k", model: "m", baseURL: URL(string: "http://localhost:1234")!
+        ).makeModel()
+        #expect(openAICompat is OpenAILanguageModel, "OpenAI-Compatible config should produce OpenAILanguageModel")
+
+        let ollama = ProviderConfiguration.ollama(model: "m").makeModel()
+        #expect(ollama is OllamaLanguageModel, "Ollama config should produce OllamaLanguageModel")
+
+        let llamaCpp = ProviderConfiguration.llamaCpp(model: "m").makeModel()
+        #expect(llamaCpp is OpenAILanguageModel, "llama.cpp config should produce OpenAILanguageModel (OpenAI-compatible)")
+
+        // On-device uses OpenAILanguageModel internally as a wrapper
+        let onDevice = ProviderConfiguration.onDeviceMLX(
+            MLXProviderConfiguration(modelId: "test")
+        ).makeModel()
+        #expect(onDevice is OpenAILanguageModel, "On-device MLX config should produce OpenAILanguageModel wrapper")
+    }
+
+    // MARK: - 2. Consistent ChatEngine-Compatible Output
+
+    @Test("Every provider mock produces valid ChatEngine responses for SELECT queries",
+          arguments: TestedProvider.allCases)
+    func providerProducesValidChatEngineResponse(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+        let mock = makeMock(for: provider, responses: [
+            "SELECT COUNT(*) FROM products",        // SQL generation
+            "There are 3 products in the database.", // Summary (fallback)
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+        let response = try await engine.send("How many products are there?")
+
+        // All providers must produce:
+        // 1. Non-empty summary
+        #expect(!response.summary.isEmpty, "\(provider.rawValue): summary must not be empty")
+
+        // 2. Valid SQL that was executed
+        #expect(response.sql == "SELECT COUNT(*) FROM products",
+                "\(provider.rawValue): SQL must match generated query")
+
+        // 3. A QueryResult with data
+        #expect(response.queryResult != nil, "\(provider.rawValue): queryResult must exist")
+        #expect(response.queryResult?.rowCount == 1, "\(provider.rawValue): should have 1 row for COUNT")
+    }
+
+    @Test("Every provider mock produces valid ChatEngine responses for multi-row SELECT",
+          arguments: TestedProvider.allCases)
+    func providerProducesMultiRowResponse(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+        let mock = makeMock(for: provider, responses: [
+            "SELECT name, price FROM products ORDER BY price DESC",
+            "Here are the products sorted by price.",
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+        let response = try await engine.send("List products by price")
+
+        #expect(response.queryResult != nil, "\(provider.rawValue): queryResult must exist")
+        #expect(response.queryResult?.rowCount == 3, "\(provider.rawValue): should return all 3 products")
+        #expect(response.queryResult?.columns.contains("name") == true,
+                "\(provider.rawValue): columns must include 'name'")
+        #expect(response.queryResult?.columns.contains("price") == true,
+                "\(provider.rawValue): columns must include 'price'")
+    }
+
+    // MARK: - 3. Consistent LanguageModelSession Integration
+
+    @Test("Every provider mock works through LanguageModelSession.respond(to:)",
+          arguments: TestedProvider.allCases)
+    func providerWorksWithSession(provider: TestedProvider) async throws {
+        let mock = makeMock(for: provider, responses: [
+            "SELECT 1 AS test",
+        ])
+
+        let session = LanguageModelSession(
+            model: mock,
+            instructions: "You are a SQL assistant."
+        )
+
+        let response = try await session.respond(to: "Generate a test query")
+
+        // Verify the response content is the expected string
+        #expect(response.content == "SELECT 1 AS test",
+                "\(provider.rawValue): session response should match mock output")
+
+        // Verify the mock received the call
+        #expect(mock.calls.count == 1, "\(provider.rawValue): should have exactly 1 call")
+        #expect(mock.calls.first?.method == "respond",
+                "\(provider.rawValue): should call respond method")
+    }
+
+    @Test("Every provider mock works through LanguageModelSession.streamResponse(to:)",
+          arguments: TestedProvider.allCases)
+    func providerWorksWithStreamSession(provider: TestedProvider) async throws {
+        let mock = makeMock(for: provider, responses: [
+            "SELECT 42 AS answer",
+        ])
+
+        let session = LanguageModelSession(
+            model: mock,
+            instructions: "You are a SQL assistant."
+        )
+
+        let stream = session.streamResponse(to: "Give me a number")
+        let collected = try await stream.collect()
+
+        #expect(collected.content == "SELECT 42 AS answer",
+                "\(provider.rawValue): stream collected response should match mock output")
+        #expect(mock.calls.count == 1, "\(provider.rawValue): should have exactly 1 call")
+        #expect(mock.calls.first?.method == "streamResponse",
+                "\(provider.rawValue): should call streamResponse method")
+    }
+
+    // MARK: - 4. Schema Introspection Works Identically Across Providers
+
+    @Test("Schema introspection returns same schema regardless of provider",
+          arguments: TestedProvider.allCases)
+    func schemaIntrospectionIsProviderAgnostic(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+        let mock = makeMock(for: provider, responses: ["SELECT 1"])
+
+        let engine = ChatEngine(database: db, model: mock)
+        let schema = try await engine.prepareSchema()
+
+        #expect(schema.tableNames.contains("products"),
+                "\(provider.rawValue): schema must include 'products' table")
+        #expect(schema.tableNames.count == 1,
+                "\(provider.rawValue): should have exactly 1 table")
+
+        let table = schema.tables["products"]
+        #expect(table != nil, "\(provider.rawValue): must find products table")
+        #expect(table?.columns.count == 4,
+                "\(provider.rawValue): products table must have 4 columns")
+    }
+
+    // MARK: - 5. Error Handling Consistency
+
+    @Test("All providers handle empty schema consistently",
+          arguments: TestedProvider.allCases)
+    func emptySchemaHandledConsistently(provider: TestedProvider) async throws {
+        let db = try DatabaseQueue(path: ":memory:")
+        let mock = makeMock(for: provider, responses: ["SELECT 1"])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        do {
+            _ = try await engine.send("Show me data")
+            Issue.record("\(provider.rawValue): should throw for empty schema")
+        } catch let error as SwiftDBAIError {
+            #expect(error == .emptySchema,
+                    "\(provider.rawValue): must throw .emptySchema for database with no tables")
+        }
+    }
+
+    @Test("All providers reject disallowed SQL operations consistently",
+          arguments: TestedProvider.allCases)
+    func disallowedSQLRejectedConsistently(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+        let mock = makeMock(for: provider, responses: [
+            "DELETE FROM products WHERE id = 1",
+        ])
+
+        // Default allowlist is readOnly (SELECT only)
+        let engine = ChatEngine(database: db, model: mock)
+
+        do {
+            _ = try await engine.send("Delete the first product")
+            Issue.record("\(provider.rawValue): should reject DELETE when allowlist is readOnly")
+        } catch {
+            // All providers must trigger the same error path for disallowed operations
+            #expect(error is SwiftDBAIError,
+                    "\(provider.rawValue): error must be SwiftDBAIError")
+        }
+    }
+
+    // MARK: - 6. Conversation History Consistency
+
+    @Test("Conversation history works identically for all providers",
+          arguments: TestedProvider.allCases)
+    func conversationHistoryConsistent(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+        // ChatEngine calls LLM for SQL generation, then TextSummaryRenderer
+        // may call LLM for summarization. For aggregate queries (COUNT, AVG),
+        // TextSummaryRenderer uses a template and skips the LLM call.
+        // So the mock sequence is: SQL1, SQL2 (each followed by template summary).
+        let mock = makeMock(for: provider, responses: [
+            "SELECT COUNT(*) FROM products",
+            "SELECT AVG(price) FROM products",
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+
+        _ = try await engine.send("How many products?")
+        _ = try await engine.send("What is the average price?")
+
+        let messages = engine.messages
+        #expect(messages.count == 4,
+                "\(provider.rawValue): should have 4 messages (2 user + 2 assistant)")
+        #expect(messages[0].role == .user, "\(provider.rawValue): first message should be user")
+        #expect(messages[1].role == .assistant, "\(provider.rawValue): second message should be assistant")
+        #expect(messages[2].role == .user, "\(provider.rawValue): third message should be user")
+        #expect(messages[3].role == .assistant, "\(provider.rawValue): fourth message should be assistant")
+
+        // Both assistant messages must have SQL
+        #expect(messages[1].sql != nil, "\(provider.rawValue): first response must have SQL")
+        #expect(messages[3].sql != nil, "\(provider.rawValue): second response must have SQL")
+    }
+
+    // MARK: - 7. ProviderConfiguration Roundtrip
+
+    @Test("All cloud provider configurations roundtrip through makeModel()")
+    func allCloudProvidersRoundtrip() {
+        let configs: [(String, ProviderConfiguration)] = [
+            ("OpenAI", .openAI(apiKey: "sk-test", model: "gpt-4o")),
+            ("OpenAI Responses", .openAI(apiKey: "sk-test", model: "gpt-4o", variant: .responses)),
+            ("Anthropic", .anthropic(apiKey: "sk-ant-test", model: "claude-sonnet-4-20250514")),
+            ("Anthropic+version", .anthropic(apiKey: "sk-ant-test", model: "claude-sonnet-4-20250514", apiVersion: "2024-01-01")),
+            ("Anthropic+betas", .anthropic(apiKey: "sk-ant-test", model: "claude-sonnet-4-20250514", betas: ["computer-use"])),
+            ("Gemini", .gemini(apiKey: "AIza-test", model: "gemini-2.0-flash")),
+            ("Gemini+version", .gemini(apiKey: "AIza-test", model: "gemini-2.0-flash", apiVersion: "v1")),
+            ("OpenAI-Compatible", .openAICompatible(
+                apiKey: "key", model: "model", baseURL: URL(string: "http://localhost:1234")!
+            )),
+            ("Ollama", .ollama(model: "llama3.2")),
+            ("Ollama+custom URL", .ollama(model: "qwen2.5", baseURL: URL(string: "http://192.168.1.100:11434")!)),
+            ("llama.cpp", .llamaCpp(model: "default")),
+            ("llama.cpp+custom", .llamaCpp(model: "my-model", baseURL: URL(string: "http://localhost:9090")!)),
+        ]
+
+        for (name, config) in configs {
+            let model = config.makeModel()
+            #expect(model.isAvailable, "\(name): model must be available after makeModel()")
+        }
+    }
+
+    @Test("On-device provider configurations produce valid models")
+    func onDeviceProvidersRoundtrip() {
+        let mlxConfigs: [MLXProviderConfiguration] = [
+            .llama3_2_3B(),
+            .qwen2_5_coder_3B(),
+            .phi3_5_mini(),
+            MLXProviderConfiguration(modelId: "custom-model", temperature: 0.2),
+        ]
+
+        for mlxConfig in mlxConfigs {
+            let providerConfig = ProviderConfiguration.onDeviceMLX(mlxConfig)
+            let model = providerConfig.makeModel()
+            #expect(model.isAvailable, "MLX model '\(mlxConfig.modelId)' must be available")
+        }
+    }
+
+    // MARK: - 8. Write Operation Allowlist Consistency
+
+    @Test("Write operations require explicit opt-in for all providers",
+          arguments: TestedProvider.allCases)
+    func writeOperationsRequireOptIn(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+
+        // Mock returns an INSERT statement
+        let mock = makeMock(for: provider, responses: [
+            "INSERT INTO products (name, price, category) VALUES ('New', 1.00, 'misc')",
+        ])
+
+        // readOnly allowlist (default)
+        let readOnlyEngine = ChatEngine(database: db, model: mock)
+
+        do {
+            _ = try await readOnlyEngine.send("Add a new product")
+            Issue.record("\(provider.rawValue): INSERT should be rejected with readOnly allowlist")
+        } catch {
+            #expect(error is SwiftDBAIError,
+                    "\(provider.rawValue): must throw SwiftDBAIError for disallowed INSERT")
+        }
+    }
+
+    @Test("Allowed write operations work for all providers",
+          arguments: TestedProvider.allCases)
+    func allowedWriteOperationsWork(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+
+        let mock = makeMock(for: provider, responses: [
+            "INSERT INTO products (name, price, category) VALUES ('NewItem', 1.00, 'misc')",
+            "Successfully added 1 product.",
+        ])
+
+        let engine = ChatEngine(
+            database: db,
+            model: mock,
+            allowlist: .standard
+        )
+
+        let response = try await engine.send("Add a product called NewItem")
+        #expect(response.sql?.uppercased().hasPrefix("INSERT") == true,
+                "\(provider.rawValue): SQL should be an INSERT")
+    }
+
+    // MARK: - 9. Response Format Consistency
+
+    @Test("ChatResponse structure is identical regardless of provider",
+          arguments: TestedProvider.allCases)
+    func responseStructureConsistent(provider: TestedProvider) async throws {
+        let db = try makeProviderTestDatabase()
+        let mock = makeMock(for: provider, responses: [
+            "SELECT name, price, category FROM products",
+            "Found 3 products across 2 categories.",
+        ])
+
+        let engine = ChatEngine(database: db, model: mock)
+        let response = try await engine.send("Show all products")
+
+        // ChatResponse must always have these properties populated
+        #expect(response.summary.count > 0,
+                "\(provider.rawValue): summary must be non-empty")
+        #expect(response.sql != nil,
+                "\(provider.rawValue): sql must be present")
+        #expect(response.queryResult != nil,
+                "\(provider.rawValue): queryResult must be present")
+
+        // QueryResult structure must match the query
+        let qr = response.queryResult!
+        #expect(qr.columns == ["name", "price", "category"],
+                "\(provider.rawValue): columns must match SELECT clause")
+        #expect(qr.rowCount == 3,
+                "\(provider.rawValue): must return all rows")
+        #expect(qr.sql == "SELECT name, price, category FROM products",
+                "\(provider.rawValue): QueryResult.sql must match executed SQL")
+        #expect(qr.executionTime >= 0,
+                "\(provider.rawValue): execution time must be non-negative")
+    }
+
+    // MARK: - 10. Provider Enum Completeness
+
+    @Test("TestedProvider covers all ProviderConfiguration.Provider cases plus on-device")
+    func testedProviderCoversAllCases() {
+        // ProviderConfiguration.Provider has 6 cases
+        let configProviderCount = ProviderConfiguration.Provider.allCases.count
+        #expect(configProviderCount == 6, "ProviderConfiguration.Provider should have 6 cases")
+
+        // TestedProvider adds on-device for 7 total
+        #expect(TestedProvider.allCases.count == 7, "TestedProvider should cover all 7 provider types")
+
+        // Verify 1:1 mapping for the config providers
+        let configNames = Set(ProviderConfiguration.Provider.allCases.map(\.rawValue))
+        for tested in TestedProvider.allCases where tested != .onDevice {
+            #expect(configNames.contains(tested.rawValue),
+                    "\(tested.rawValue) must map to a ProviderConfiguration.Provider case")
+        }
+    }
+
+    // MARK: - 11. ChatEngine Convenience Init Consistency
+
+    @Test("ChatEngine convenience init with ProviderConfiguration works for all cloud providers")
+    func chatEngineConvenienceInitWorks() throws {
+        let db = try makeProviderTestDatabase()
+
+        let configs: [ProviderConfiguration] = [
+            .openAI(apiKey: "test", model: "gpt-4o"),
+            .anthropic(apiKey: "test", model: "claude-sonnet-4-20250514"),
+            .gemini(apiKey: "test", model: "gemini-2.0-flash"),
+            .openAICompatible(apiKey: "test", model: "m", baseURL: URL(string: "http://localhost:1234")!),
+            .ollama(model: "llama3.2"),
+            .llamaCpp(model: "default"),
+        ]
+
+        for config in configs {
+            // This should not throw — it only creates the engine, doesn't call the LLM
+            let engine = ChatEngine(database: db, provider: config)
+            #expect(engine.tableCount == nil, "tableCount should be nil before first query")
+        }
+    }
+
+    // MARK: - 12. Availability Reporting
+
+    @Test("All real provider models report available by default")
+    func allModelsReportAvailable() {
+        let models: [(String, any LanguageModel)] = [
+            ("OpenAI", OpenAILanguageModel(apiKey: "k", model: "m")),
+            ("Anthropic", AnthropicLanguageModel(apiKey: "k", model: "m")),
+            ("Gemini", GeminiLanguageModel(apiKey: "k", model: "m")),
+            ("Ollama", OllamaLanguageModel(model: "m")),
+        ]
+
+        for (name, model) in models {
+            #expect(model.isAvailable, "\(name) should be available by default")
+        }
+    }
+
+    // MARK: - 13. On-Device Pipeline Status
+
+    @Test("On-device inference pipeline starts in notLoaded state")
+    func onDevicePipelineInitialState() {
+        let mlxPipeline = OnDeviceInferencePipeline(
+            mlxConfiguration: .llama3_2_3B()
+        )
+        #expect(mlxPipeline.status == .notLoaded)
+        #expect(mlxPipeline.providerType == .mlx)
+
+        let coreMLPipeline = OnDeviceInferencePipeline(
+            coreMLConfiguration: CoreMLProviderConfiguration(
+                modelURL: URL(fileURLWithPath: "/tmp/test.mlmodelc")
+            )
+        )
+        #expect(coreMLPipeline.status == .notLoaded)
+        #expect(coreMLPipeline.providerType == .coreML)
+    }
+
+    @Test("On-device SQL generation hints are populated for both provider types")
+    func onDeviceSQLHints() {
+        let mlxPipeline = OnDeviceInferencePipeline(mlxConfiguration: .llama3_2_3B())
+        let mlxHints = mlxPipeline.recommendedSQLGenerationHints
+        #expect(mlxHints.maxTokens > 0)
+        #expect(mlxHints.temperature >= 0)
+        #expect(!mlxHints.systemPromptSuffix.isEmpty)
+
+        let coreMLPipeline = OnDeviceInferencePipeline(
+            coreMLConfiguration: CoreMLProviderConfiguration(
+                modelURL: URL(fileURLWithPath: "/tmp/test.mlmodelc")
+            )
+        )
+        let coreMLHints = coreMLPipeline.recommendedSQLGenerationHints
+        #expect(coreMLHints.maxTokens > 0)
+        #expect(coreMLHints.temperature >= 0)
+        #expect(!coreMLHints.systemPromptSuffix.isEmpty)
+    }
+}

seed.yaml

@@ -0,0 +1,191 @@
+###############################################################################
+# SwiftDBAI — Seed Specification
+# Generated from Socratic interview on 2026-04-03
+###############################################################################
+
+goal: >
+  Build SwiftDBAI — a Swift package that lets users chat with any SQLite
+  database using natural language. Built on AnyLanguageModel (HuggingFace)
+  for LLM-agnostic provider support and GRDB for SQLite access. Ships a
+  drop-in SwiftUI ChatView, a headless ChatEngine, auto-schema introspection,
+  and result rendering with text, tables, and Swift Charts.
+
+constraints:
+  - Swift 6.1+ with strict concurrency checking
+  - Swift Package Manager only (no CocoaPods/Carthage)
+  - iOS 17.0+, macOS 14.0+, visionOS 1.0+
+  - GRDB for all SQLite access (no raw sqlite3 C API)
+  - AnyLanguageModel (HuggingFace) as the sole LLM abstraction layer
+  - Any SQLite database supported (not limited to SwiftData)
+  - No UIKit dependency — pure SwiftUI for the view layer
+  - No Apple Intelligence / Foundation Models dependency
+  - Developer provides their own GRDB DatabasePool or DatabaseQueue
+  - SQL operation allowlist configured by developer (SELECT, INSERT, UPDATE, DELETE)
+  - No SQL parser — allowlist check is sufficient for validation
+  - Zero telemetry — the package collects nothing
+
+acceptance_criteria:
+  - Auto-introspects any SQLite database schema from sqlite_master (tables, columns, types, foreign keys)
+  - LLM generates valid SQL queries from natural language input
+  - Query results render as natural language text summaries
+  - Query results render as scrollable data tables
+  - Aggregate/numeric results render as Swift Charts
+  - Drop-in DataChatView works with minimal setup (< 10 lines of code)
+  - Headless ChatEngine supports programmatic query/response without UI
+  - Multi-turn conversation context maintained (follow-up queries work)
+  - Mutation operations (INSERT, UPDATE, DELETE) work when allowlisted
+  - Destructive operations require confirmation via ToolExecutionDelegate
+  - All AnyLanguageModel providers work (OpenAI, Anthropic, Gemini, Ollama, CoreML, MLX, llama.cpp)
+  - Error states (bad SQL, LLM failure, schema mismatch) handled gracefully in UI
+  - Package binary adds < 2 MB to app (excluding LLM model weights)
+
+ontology_schema:
+  name: SwiftDBAI
+  description: >
+    Domain model for a conversational SQLite query engine that bridges
+    natural language, LLM tool calls, SQL generation, and result rendering.
+  fields:
+    - name: database_schema
+      type: object
+      description: >
+        Auto-introspected SQLite schema containing tables, columns
+        (name, type, nullable, default), primary keys, foreign keys,
+        and indexes. Derived from sqlite_master at init time.
+
+    - name: chat_engine
+      type: object
+      description: >
+        Orchestrator that manages the conversation loop: accepts user
+        messages, injects schema context into the LLM system prompt,
+        calls AnyLanguageModel LanguageModelSession with registered
+        SQL tools, executes resulting SQL, and formats responses.
+
+    - name: sql_tools
+      type: array
+      description: >
+        AnyLanguageModel Tool conformances: QueryTool (SELECT),
+        InsertTool (INSERT), UpdateTool (UPDATE), DeleteTool (DELETE),
+        AggregateTool (COUNT/SUM/AVG/MIN/MAX). Each uses @Generable
+        arguments. Developer's allowlist controls which tools are active.
+
+    - name: query_result
+      type: object
+      description: >
+        Structured result from SQL execution containing: raw rows
+        (array of dictionaries), column metadata, row count, execution
+        time, and the generated SQL string for transparency.
+
+    - name: chat_message
+      type: object
+      description: >
+        A single message in the conversation. Has a role (user/assistant/system),
+        text content, optional query_result attachment, optional chart_data
+        for Swift Charts rendering, and a timestamp.
+
+    - name: chat_view
+      type: object
+      description: >
+        Drop-in SwiftUI view that renders chat_messages with three
+        result modes: text summary, data table, and Swift Charts.
+        Handles input, loading states, error display, and confirmation
+        dialogs for mutations. Themeable.
+
+    - name: operation_allowlist
+      type: object
+      description: >
+        Developer-configured set of permitted SQL operations. Maps to
+        mutationPolicy: readOnly (SELECT only), standard (SELECT + INSERT +
+        UPDATE), unrestricted (all including DELETE), or custom set.
+
+    - name: llm_provider
+      type: object
+      description: >
+        Any AnyLanguageModel-compatible language model instance passed
+        by the developer. The kit never instantiates providers itself —
+        developer chooses and configures their preferred backend.
+
+evaluation_principles:
+  - name: zero_config_reads
+    description: >
+      A developer with an existing SQLite database should be able to
+      chat with their data by providing only a GRDB connection and an
+      AnyLanguageModel instance. No schema files, no annotations, no setup.
+    weight: 0.25
+
+  - name: sql_correctness
+    description: >
+      Generated SQL must be valid for the target schema. Column names,
+      table names, and types must match the introspected schema. Queries
+      should not reference non-existent tables or columns.
+    weight: 0.25
+
+  - name: safety_by_default
+    description: >
+      The default configuration must be read-only (SELECT only). Write
+      operations require explicit opt-in via the allowlist. Destructive
+      operations (DELETE, DROP) must require confirmation even when allowed.
+    weight: 0.20
+
+  - name: provider_agnosticism
+    description: >
+      All features must work identically regardless of which AnyLanguageModel
+      provider is used. No provider-specific code paths in the core kit.
+      Tool definitions must use standard AnyLanguageModel Tool protocol.
+    weight: 0.15
+
+  - name: rendering_quality
+    description: >
+      Results must be presented clearly: text summaries are natural and
+      concise, data tables are scrollable and readable, charts are
+      auto-selected based on data shape (bar for categories, line for
+      time series, pie for proportions).
+    weight: 0.15
+
+exit_conditions:
+  - name: core_query_loop
+    description: User can type a natural language question and get correct SQL results
+    criteria: >
+      End-to-end works: NL input → schema context → LLM tool call →
+      SQL generation → GRDB execution → formatted response in ChatView
+
+  - name: all_result_modes
+    description: All three rendering modes (text, table, chart) work
+    criteria: >
+      Text summaries render for all queries. Data tables render for
+      multi-row results. Swift Charts render for numeric/aggregate data.
+
+  - name: mutation_safety
+    description: Write operations are safe and controllable
+    criteria: >
+      Allowlist correctly blocks disallowed operations. Confirmation
+      dialog appears for destructive ops. Mutations execute correctly
+      when confirmed.
+
+  - name: multi_provider
+    description: Works with at least 3 different AnyLanguageModel providers
+    criteria: >
+      Tested with OpenAI, Anthropic, and Ollama. Same queries produce
+      equivalent results across providers.
+
+  - name: integration_time
+    description: New developer can integrate in under 5 minutes
+    criteria: >
+      README example compiles and runs. DataChatView renders and
+      responds to queries with < 10 lines of setup code.
+
+metadata:
+  version: "1.0"
+  generated: "2026-04-03"
+  source: socratic_interview
+  ambiguity_score: 0.15
+  interview_decisions:
+    data_layer: "All SQL via GRDB (not SwiftData APIs)"
+    scope: "Any SQLite database"
+    schema_discovery: "Auto-introspect from sqlite_master"
+    safety_model: "Developer-configured operation allowlist"
+    sql_validation: "Allowlist check only (no SQL parser)"
+    connection_model: "Developer passes GRDB DatabasePool/DatabaseQueue"
+    ui_rendering: "Text + data table + Swift Charts"
+    target_audience: "Both app developers (ChatView) and debuggers (headless)"
+    timeline: "6-8 weeks, polished release"
+    llm_layer: "AnyLanguageModel (HuggingFace)"