XC-MCP: XCode CLI wrapper

# XC-MCP: Intelligent Xcode MCP Server [](https://www.npmjs.com/package/xc-mcp) [](https://www.npmjs.com/package/xc-mcp) [](https://nodejs.org) [](https://codecov.io/gh/conorluddy/xc-mcp) [](https://deepwiki.com/conorluddy/xc-mcp) [](https://opensource.org/licenses/MIT) **Production-grade MCP server for Xcode workflows — optimized for AI agents with accessibility-first iOS automation** XC-MCP makes Xcode and iOS simulator tooling accessible to AI agents through intelligent context engineering. **V3.0.0 adds platform-native `defer_loading` support** — Claude's tool search automatically discovers tools on-demand, minimizing baseline context overhead while maintaining full 29-tool functionality. <img width="807" height="727" alt="Screenshot 2025-11-07 at 08 37 00" src="https://github.com/user-attachments/assets/141de013-947e-458e-acaf-91c039f0f48e" /> --- ## Why XC-MCP? ### The Problem: Token Overflow Breaks MCP Clients Traditional Xcode CLI wrappers dump massive output that exceeds MCP protocol limits: - `simctl list`: 57,000+ tokens (unusable in MCP context) - Build logs: 135,000+ tokens (catastrophic overflow) - Screenshot-first automation: 170 tokens per screen, 2000ms latency - No state memory between operations ### The Solution: Progressive Disclosure + Accessibility-First **V3.0.0 Architecture:** ``` Platform-native defer_loading on all 29 tools ├─ Claude's tool search discovers tools automatically ├─ Tools loaded on-demand (minimal baseline overhead) ├─ Accessibility-first workflow (50 tokens, 120ms vs 170 tokens, 2000ms) └─ Workflow tools for common operations (fresh-install, tap-element) ``` **Token Efficiency Evolution:** | Version | Baseline Tokens | Total Tools | Architecture | Context Available | |---------|-----------------|-------------|--------------|-------------------| | Pre-RTFM (v1.2.1) | ~45k | 51 | Individual tools | 3.9% (155k) | | V1.3.2 (RTFM) | ~30k | 51 | Individual + RTFM | 1.5% (170k) | | V2.0.0 | ~18.7k | 28 | Routers + Full Docs | 9.3% (181k) | | **V3.0.0** | **~0** | **29** | **Platform defer_loading** | **100% (200k)** | **Key Improvements (V3.0.0):** - ✅ **Platform-native defer_loading** - All tools deferred; Claude discovers on-demand - ✅ **Workflow tools** - High-level abstractions for common operations - ✅ **Zero baseline overhead** - Platform handles tool discovery - ✅ **Accessibility-first automation** (3-4x faster, 3-4x cheaper than screenshots) - ✅ **Progressive disclosure** (summaries → cache IDs → full details on demand) - ✅ **60% test coverage** with comprehensive error handling --- ## Quick Start ```bash # Install globally npm install -g xc-mcp # Or run without installation npx xc-mcp ``` **MCP Configuration** (Claude Desktop): Add to `~/Library/Application Support/Claude/claude_desktop_config.json`: ```json { "mcpServers": { "xc-mcp": { "command": "npx", "args": ["-y", "xc-mcp"] } } } ``` **Minimal Mode** (for Claude Code and other clients that don't support `defer_loading`): ```json { "mcpServers": { "xc-mcp": { "command": "npx", "args": ["-y", "xc-mcp", "--mini"] } } } ``` The `--mini` flag reduces tool descriptions from ~18.7k tokens to ~540 tokens (~97% reduction). Use `rtfm` for full documentation on-demand. **Build-Only Mode** (for build-focused workflows without UI automation): ```json { "mcpServers": { "xc-mcp": { "command": "npx", "args": ["-y", "xc-mcp", "--build-only"] } } } ``` The `--build-only` flag loads only 11 tools (vs 30): xcodebuild tools, simctl-list, cache, and system tools. Excludes IDB/UI automation and workflow tools. Combine with `--mini` for maximum reduction: `["--mini", "--build-only"]`. --- ## Token Optimization Architecture ### Progressive Disclosure Pattern XC-MCP returns concise summaries first, with cache IDs for on-demand detail retrieval: **Example: Simulator List** (96% token reduction) ```typescript // 1. Get summary (2,000 tokens vs 57,000 raw) simctl-list({ deviceType: "iPhone" }) // Returns: { cacheId: "sim-abc123", summary: { totalDevices: 47, availableDevices: 31, bootedDevices: 1 }, quickAccess: { bootedDevices: [...], recentlyUsed: [...] } } // 2. Get full details only if needed simctl-get-details({ cacheId: "sim-abc123", detailType: "available-only", maxDevices: 10 }) ``` **Example: Build Operations** ```typescript // 1. Build returns summary + buildId xcodebuild-build({ projectPath: "./MyApp.xcworkspace", scheme: "MyApp" }) // Returns: { buildId: "build-xyz789", success: true, summary: { duration: 7075, errorCount: 0, warningCount: 1 } } // 2. Access full logs only when debugging xcodebuild-get-details({ buildId: "build-xyz789", detailType: "full-log" }) ``` ### RTFM On-Demand Documentation **Discovery Workflow:** ```typescript // 1. Browse tool categories rtfm({ categoryName: "build" }) // Returns: List of build tools with brief descriptions // 2. Get comprehensive docs for specific tool rtfm({ toolName: "xcodebuild-build" }) // Returns: Full documentation with parameters, examples, related tools // 3. Execute with consolidated operations xcodebuild-build({ scheme: "MyApp", configuration: "Debug" }) ``` **Why RTFM?** - Tool descriptions: <10 words + "See rtfm for details" - Full docs retrieved only when needed - 80% token savings vs traditional verbose MCP servers ### Operation Enum Consolidation **Before V2.0:** 21 individual tools ```typescript simctl-boot, simctl-shutdown, simctl-create, simctl-delete, simctl-erase, simctl-clone, simctl-rename, simctl-install, simctl-uninstall, simctl-launch, simctl-terminate... ``` **V2.0:** 6 consolidated routers ```typescript simctl-device({ operation: "boot" | "shutdown" | "create" | "delete" | "erase" | "clone" | "rename" }) simctl-app({ operation: "install" | "uninstall" | "launch" | "terminate" }) idb-app({ operation: "install" | "uninstall" | "launch" | "terminate" }) cache({ operation: "get-stats" | "get-config" | "set-config" | "clear" }) persistence({ operation: "enable" | "disable" | "status" }) idb-targets({ operation: "list" | "describe" | "connect" | "disconnect" }) ``` **Result:** 40% token reduction through shared parameter schemas and unified documentation. --- ## Accessibility-First iOS Automation ### Our Philosophy XC-MCP promotes **accessibility-first** automation because it: 1. **Encourages better apps**: Developers building accessible UIs benefit all users (screen readers, voice control, assistive technologies) 2. **Enables precise AI interaction**: Semantic element discovery via accessibility tree vs visual guesswork from screenshots 3. **Improves efficiency**: 3-4x faster execution, 3-4x cheaper token cost 4. **Reduces energy usage**: Skip computationally expensive image processing entirely ### Objective Performance Data | Approach | Tokens | Latency | Use Case | |----------|--------|---------|----------| | **Accessibility Tree** | ~50 | ~120ms | Rich UIs with >3 tappable elements | | **Screenshot Analysis** | ~170 | ~2000ms | Minimal UIs with ≤1 tappable element | | **Efficiency Gain** | **3.4x cheaper** | **16x faster** | When accessibility sufficient | ### Accessibility-First Workflow ```typescript // 1. ALWAYS assess quality first accessibility-quality-check({ screenContext: "LoginScreen" }) // Returns: { quality: "rich" | "moderate" | "minimal", recommendation: "accessibility-ready" | "consider-screenshot", elementCounts: { total: 12, tappable: 8, textFields: 2 } } // 2. Decision branch based on quality if (quality === "rich" || quality === "moderate") { // Use accessibility tree (faster, cheaper) idb-ui-find-element({ query: "login" }) // Returns: { centerX: 200, centerY: 400, label: "Login" } idb-ui-tap({ x: 200, y: 400 }) // Precise coordinate-based interaction } else if (quality === "minimal") { // Fall back to screenshot (last resort) screenshot({ size: "half", screenName: "LoginScreen" }) // Visual analysis when accessibility insufficient } ``` **Why This Matters:** - **For Users**: Encourages inclusive app development benefiting everyone - **For AI Agents**: Precise semantic targeting vs visual pattern matching - **For Efficiency**: 50 tokens (accessibility) vs 170 tokens (screenshot) - **For Speed**: 120ms (accessibility) vs 2000ms (screenshot) - **For Energy**: Skip image encoding/decoding/analysis entirely ### Accessibility Tools (3 specialized) **`accessibility-quality-check`**: Rapid assessment without full tree query - Returns: `rich` (>3 tappable) | `moderate` (2-3) | `minimal` (≤1) - Use case: Decision point before screenshot vs accessibility - Cost: ~30 tokens, ~80ms **`idb-ui-find-element`**: Semantic element search by label/identifier - Returns: Tap-ready coordinates (centerX, centerY) with frame boundaries - Use case: Find specific button, field, or cell without visual analysis - Cost: ~40 tokens, ~120ms **`idb-ui-describe`**: Full accessibility tree with progressive disclosure - Operation `all`: Summary + uiTreeId for full tree retrieval - Operation `point`: Element details at specific coordinates - Use case: Discover all interactive elements, validate tap coordinates - Cost: ~50 tokens for summary, ~500 tokens for full tree --- ## Platform defer_loading (V3.0.0 Feature) ### How It Works XC-MCP V3.0 adds the `defer_loading: true` flag to all 29 tool registrations. Claude's platform-native tool search automatically: 1. **Discovers tools on-demand** — No custom tool-search implementation needed 2. **Loads tools when relevant** — Based on conversation context 3. **Minimizes baseline overhead** — Zero tokens at startup ### RTFM: On-Demand Documentation Use `rtfm` to get comprehensive documentation for any tool: ```typescript // 1. Browse tool categories rtfm({ categoryName: "build" }) // Returns all build-related tools with descriptions // 2. Get comprehensive docs for specific tool rtfm({ toolName: "xcodebuild-build" }) // Returns full documentation with parameters, examples, related tools // 3. Execute with discovered parameters xcodebuild-build({ scheme: "MyApp", configuration: "Debug" }) ``` ### Environment Variable: Disable defer_loading **Default (V3.0.0)**: All tools have defer_loading enabled ```bash # Platform discovers and loads tools automatically # Zero baseline token overhead ``` **Disable defer_loading** (for debugging/testing): ```bash # Set environment variable to load all tools at startup export XC_MCP_DEFER_LOADING=false # All 29 tools loaded immediately (~18.7k tokens) # Useful for: Testing, debugging, MCP client compatibility ``` --- ## Workflow Tools (New in V3.0.0) XC-MCP provides 2 high-level **workflow tools** that combine common operations into single steps: ### `workflow-tap-element` — High-Level Semantic Tap Combines accessibility quality check + element search + tap into one operation: ```typescript workflow-tap-element({ elementQuery: "Login", screenContext: "LoginScreen", inputText: "user@example.com", // optional: type after tap verifyResult: true // optional: screenshot after action }) // Does: // 1. Quality check screen accessibility // 2. Find element by name/label // 3. Tap coordinates // 4. Optionally type text // 5. Optionally take verification screenshot // Returns: { success: true, tappedElement: {...}, screenshot?: {...} } ``` **Cost**: ~90 tokens (vs 130 tokens separately) **Latency**: ~300ms (vs ~400ms separately) **Use case**: User login, form submission, navigation flows ### `workflow-fresh-install` — Clean Install Workflow Performs complete app refresh: shutdown → (erase) → boot → build → install → launch ```typescript workflow-fresh-install({ projectPath: "./MyApp.xcworkspace", scheme: "MyApp", simulatorUdid: "...", // optional: auto-detects eraseSimulator: true, // optional: wipe simulator data configuration: "Debug", launchArguments: ["--resetData"] }) // Does: // 1. Shutdown simulator if running // 2. Erase simulator state (if requested) // 3. Boot simulator fresh // 4. Build app // 5. Install app // 6. Launch app with arguments // Returns: { success: true, buildTime: 7000, bootTime: 3000, launchTime: 500 } ``` **Cost**: ~200 tokens (vs 300+ tokens separately) **Latency**: ~20s (vs 25+ seconds separately) **Use case**: CI/CD pipelines, clean state testing, fresh debugging sessions --- ## Tool Reference ### 6 Consolidated Router Tools **`simctl-device`** — Simulator lifecycle (7 operations) - `boot`, `shutdown`, `create`, `delete`, `erase`, `clone`, `rename` - Auto-UDID detection, performance tracking, smart defaults **`simctl-app`** — App management (4 operations) - `install`, `uninstall`, `launch`, `terminate` - Bundle ID resolution, launch arguments, environment variables **`idb-app`** — IDB app operations (4 operations) - `install`, `uninstall`, `launch`, `terminate` - Physical device + simulator support via IDB **`cache`** — Cache management (4 operations) - `get-stats`, `get-config`, `set-config`, `clear` - Multi-layer caching (simulator, project, response, build settings) **`persistence`** — Persistence control (3 operations) - `enable`, `disable`, `status` - File-based cache across server restarts **`idb-targets`** — Target management (2 operations) - `list`, `describe`, `connect`, `disconnect` - Physical device and simulator discovery ### 22 Individual Specialized Tools **Build & Test (6 tools)** - `xcodebuild-build`: Build with progressive disclosure via buildId - `xcodebuild-test`: Test with filtering, test plans, cache IDs - `xcodebuild-clean`: Clean build artifacts - `xcodebuild-list`: List targets/schemes with smart caching - `xcodebuild-version`: Get Xcode and SDK versions - `xcodebuild-get-details`: Access cached build/test logs **UI Automation (6 tools)** - `idb-ui-describe`: Accessibility tree queries (all | point operations) - `idb-ui-tap`: Coordinate-based tapping with percentage conversion - `idb-ui-input`: Text input with keyboard control - `idb-ui-gesture`: Swipes, pinches, rotations with coordinate transforms - `idb-ui-find-element`: Semantic element search (NEW in v2.0) - `accessibility-quality-check`: Rapid UI richness assessment (NEW in v2.0) **I/O & Media (2 tools)** - `simctl-io`: Screenshots and video recording with semantic naming - `screenshot`: Vision-optimized base64 screenshots (inline, max 800px) **Discovery & Health (3 tools)** - `simctl-list`: Progressive disclosure simulator listing (96% token reduction) - `simctl-get-details`: On-demand full simulator data retrieval - `simctl-health-check`: Xcode environment validation **Utilities (5 tools)** - `simctl-openurl`: Open URLs and deep links - `simctl-get-app-container`: Get app container paths (bundle, data, group) - `simctl-push`: Simulate push notifications - `rtfm`: On-demand comprehensive documentation **Workflow Tools (2 high-level abstractions) - NEW in V3.0.0** - `workflow-tap-element`: High-level semantic tap (find + tap in one call) - `workflow-fresh-install`: Clean install workflow (shutdown → erase → boot → build → install → launch) **Total: 29 active tools** (27 core + 2 workflow abstractions) --- ## Usage Examples ### Example 1: Accessibility-First Login Automation ```typescript // 1. Quality check before choosing approach accessibility-quality-check({ screenContext: "LoginScreen" }) // → { quality: "rich", tappableElements: 12, textFields: 2 } // 2. Find email field semantically idb-ui-find-element({ query: "email" }) // → { centerX: 200, centerY: 150, label: "Email", type: "TextField" } // 3. Tap and input email idb-ui-tap({ x: 200, y: 150 }) idb-ui-input({ operation: "text", text: "user@example.com" }) // 4. Find and tap login button idb-ui-find-element({ query: "login" }) // → { centerX: 200, centerY: 400, label: "Login", type: "Button" } idb-ui-tap({ x: 200, y: 400 }) // 5. Verify (screenshot only for confirmation, not primary interaction) screenshot({ screenName: "HomeScreen", state: "LoggedIn" }) ``` **Efficiency Comparison:** - **Accessibility approach**: 4 queries × 50 tokens = 200 tokens, ~500ms total - **Screenshot approach**: 3 screenshots × 170 tokens = 510 tokens, ~6000ms total - **Savings**: 2.5x cheaper, 12x faster ### Example 2: RTFM Discovery Workflow ```typescript // 1. Browse tool categories rtfm({ categoryName: "build" }) // Returns: { category: "build", tools: [ { name: "xcodebuild-build", description: "Build Xcode projects with smart defaults" }, { name: "xcodebuild-test", description: "Run tests with filtering and test plans" }, ... ] } // 2. Get comprehensive docs for specific tool rtfm({ toolName: "xcodebuild-build" }) // Returns: { tool: "xcodebuild-build", description: "Full comprehensive documentation...", parameters: { projectPath: "...", scheme: "...", configuration: "..." }, examples: [...], relatedTools: ["xcodebuild-clean", "xcodebuild-get-details"] } // 3. Execute with discovered parameters xcodebuild-build({ projectPath: "./MyApp.xcworkspace", scheme: "MyApp", configuration: "Debug" }) ``` ### Example 3: Progressive Disclosure Build Workflow ```typescript // 1. Build returns summary + buildId xcodebuild-build({ projectPath: "./MyApp.xcworkspace", scheme: "MyApp" }) // Returns: { buildId: "build-abc123", success: true, summary: { duration: 7075, errorCount: 0, warningCount: 1, configuration: "Debug", sdk: "iphonesimulator" }, nextSteps: [ "Build completed successfully", "Use 'xcodebuild-get-details' with buildId for full logs" ] } // 2. Access full logs only when debugging xcodebuild-get-details({ buildId: "build-abc123", detailType: "full-log", maxLines: 100 }) // Returns: Full compiler output, warnings, errors ``` --- ## CLAUDE.md Template for End Users Copy this into your project's `CLAUDE.md` to guide AI agents toward optimal XC-MCP usage: ```markdown # XC-MCP Optimal Usage Patterns This project uses XC-MCP for iOS development automation. Follow these patterns for maximum efficiency. ## Tool Discovery 1. **Browse categories**: `rtfm({ categoryName: "build" })` — See all build-related tools 2. **Get tool docs**: `rtfm({ toolName: "xcodebuild-build" })` — Comprehensive documentation 3. **Execute**: Use discovered parameters and operations ## Accessibility-First Automation (MANDATORY) **ALWAYS assess accessibility quality before taking screenshots:** 1. **Check quality**: `accessibility-quality-check({ screenContext: "LoginScreen" })` - Returns: `rich` | `moderate` | `minimal` 2. **Decision branch**: - IF `rich` or `moderate`: Use `idb-ui-find-element` + `idb-ui-tap` (faster, cheaper) - IF `minimal`: Fall back to `screenshot` (last resort) 3. **Why this matters**: - Accessibility: 50 tokens, 120ms per query - Screenshots: 170 tokens, 2000ms per capture - **3-4x cheaper, 16x faster when accessibility sufficient** - **Promotes inclusive app development** ## Progressive Disclosure - Build/test tools return `buildId` or cache IDs - Use `xcodebuild-get-details` or `simctl-get-details` to drill down - **Never request full logs upfront** — get summaries first ## Best Practices - **Let UDID auto-detect** — Don't prompt user for simulator UDIDs - **Use semantic context** — Include `screenContext`, `appName`, `screenName` parameters - **Prefer accessibility over screenshots** — Better for efficiency AND app quality - **Use operation enums** — `simctl-device({ operation: "boot" })` instead of separate tools ## Example: Optimal Login Flow \`\`\`typescript // 1. Quality check (30 tokens, 80ms) accessibility-quality-check({ screenContext: "LoginScreen" }) // 2. IF rich: Semantic search (40 tokens, 120ms) idb-ui-find-element({ query: "email" }) idb-ui-tap({ x: 200, y: 150 }) idb-ui-input({ operation: "text", text: "user@example.com" }) idb-ui-find-element({ query: "login" }) idb-ui-tap({ x: 200, y: 400 }) // 3. Verify with screenshot only at end (170 tokens, 2000ms) screenshot({ screenName: "HomeScreen", state: "LoggedIn" }) // Total: ~280 tokens, ~2400ms // vs Screenshot-first: ~510 tokens, ~6000ms (2.5x slower, 1.8x more expensive) \`\`\` ``` --- ## Installation & Configuration ### Prerequisites - macOS with Xcode command-line tools - Node.js 18+ - Xcode 15+ recommended Install Xcode CLI tools: ```bash xcode-select --install ``` ### Installation Options ```bash # Global install (recommended for MCP) npm install -g xc-mcp # Or run directly without installation npx -y xc-mcp # Local development git clone https://github.com/conorluddy/xc-mcp.git cd xc-mcp && npm install && npm run build ``` ### MCP Client Configuration **Claude Desktop** (`~/Library/Application Support/Claude/claude_desktop_config.json`): ```json { "mcpServers": { "xc-mcp": { "command": "npx", "args": ["-y", "xc-mcp"], "cwd": "/path/to/your/ios/project" } } } ``` **Environment Variables** (optional): - `XCODE_CLI_MCP_TIMEOUT`: Operation timeout in seconds (default: 300) - `XCODE_CLI_MCP_LOG_LEVEL`: Logging verbosity (debug | info | warn | error) - `XCODE_CLI_MCP_CACHE_DIR`: Custom cache directory path - `XC_MCP_DEFER_LOADING`: Enable deferred tool loading (default: true for V3.0) --- ## Breaking Changes & Migration Guide ### V3.0.0: Platform defer_loading Support **What Changed:** - All 29 tools now have `defer_loading: true` flag - Claude's platform tool search discovers tools automatically - No custom tool-search implementation needed - Tools loaded on-demand based on conversation context **Migration Path:** | Scenario | Action | Notes | |----------|--------|-------| | **New Projects** | No action needed | Platform handles discovery | | **Existing Integrations** | No action needed | Compatible with V2.x usage | | **Debugging/Testing** | Set env var | Use `XC_MCP_DEFER_LOADING=false` | **Usage (same as V2.x):** ```typescript // V3.0 - Platform discovers tools automatically // Just use tools as before - Claude's tool search handles discovery xcodebuild-build({ scheme: "MyApp" }) // Use RTFM for documentation discovery rtfm({ categoryName: "build" }) rtfm({ toolName: "xcodebuild-build" }) // Disable defer_loading for debugging export XC_MCP_DEFER_LOADING=false ``` **Token Impact:** | Version | Startup | Discovery | Notes | |---------|---------|-----------|-------| | V2.0.x | ~18.7k | N/A | All tools loaded upfront | | **V3.0.0** | **~0** | **Platform-managed** | Tools loaded on-demand | --- ## Development ### Build Commands ```bash npm run build # Compile TypeScript to JavaScript npm run dev # Development mode with watch compilation npm test # Run Jest test suite (60% coverage) npm run test:coverage # Generate coverage report npm run lint # ESLint with auto-fix npm run format # Prettier code formatting ``` ### Testing - **Jest** with ESM support and TypeScript compilation - **60% coverage** across statements, branches, functions, lines - **1136 tests** covering core functionality, edge cases, error handling - **Pre-commit hooks** enforce code quality via Husky + lint-staged ### Architecture **Core Components:** - `src/index.ts` — MCP server with tool registration and routing - `src/tools/` — 29 tools organized by category (xcodebuild, simctl, idb, cache, workflows) - `src/state/` — Multi-layer intelligent caching (simulator, project, response, build settings) - `src/utils/` — Shared utilities (command execution, validation, error formatting) - `src/types/` — TypeScript definitions for Xcode data structures **Cache Architecture:** - **Simulator Cache**: 1-hour retention, usage tracking, performance metrics - **Project Cache**: Remembers successful build configurations per project - **Build Settings Cache**: Auto-discovers bundle IDs, deployment targets, capabilities - **Response Cache**: 30-minute retention for progressive disclosure --- ## Contributing Contributions welcome! Please ensure: - Tests pass (`npm test`) - Coverage remains ≥60% (`npm run test:coverage`) - Code passes linting (`npm run lint`) - TypeScript compiles (`npm run build`) See [CLAUDE.md](./CLAUDE.md) for detailed development guidelines and architecture documentation. --- ## License MIT License — See [LICENSE](./LICENSE) for details. --- **XC-MCP: Production-grade Xcode automation for AI agents through progressive disclosure and accessibility-first workflows.**