Preflight MCP

The most comprehensive MCP (Model Context Protocol) server for iOS Simulator automation. Gives AI agents like Claude, ChatGPT, Cursor, Windsurf, and any MCP-compatible tool full control over iOS Simulators — tap, swipe, type, read accessibility trees, inspect app data, capture screenshots, record video, manage devices, and debug apps in real time.

82 tools across 14 categories. Zero cursor interference — works silently in the background while you use your Mac.

Inspired by Playwright MCP for web automation — Preflight brings the same structured accessibility-first approach to iOS.

Why Preflight?

• No disk clutter — Screenshots and video frames return directly in chat. No folders filling up.
• AI-optimized — Images compressed for minimal token usage. Video → key frames (most AI models can't view video files).
• Accessibility-first — Like Playwright's browser_snapshot, use simulator_snapshot to understand the screen without vision models.
• Cursor-free — Touch injection via idb (IndigoHID) — your Mac cursor stays put.
• 82 tools — From basic tap/swipe to StoreKit testing, network conditioning, memory profiling, and crash log analysis.

Quick Start

Prerequisites

• macOS with Xcode and iOS Simulator installed
• Node.js 18+
• Facebook idb (recommended for cursor-free operation)

Install idb (recommended)

brew tap facebook/fb
brew install idb-companion
pip3 install fb-idb

Without idb, the server falls back to CGEvent mouse injection (works but briefly moves your cursor).

Install via npm (recommended)

npm install -g preflight-ios-mcp

Build from Source

git clone https://github.com/EthanAckerman-git/Preflight.git
cd Preflight
npm install
npm run build

Setup by IDE / AI Tool

Add your Python bin directory to PATH if idb was installed via pip (e.g., ~/Library/Python/3.x/bin).

Claude Code

claude mcp add preflight -- npx preflight-ios-mcp

Or add to .mcp.json in your project root:

{
  "mcpServers": {
    "preflight": {
      "command": "npx",
      "args": ["preflight-ios-mcp"],
      "env": {
        "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}

Cursor

Add to ~/.cursor/mcp.json (global) or .cursor/mcp.json (per-project):

{
  "mcpServers": {
    "preflight": {
      "command": "npx",
      "args": ["preflight-ios-mcp"],
      "env": {
        "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}

Then in Cursor: Settings → MCP — verify "preflight" shows as connected.

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "preflight": {
      "command": "npx",
      "args": ["preflight-ios-mcp"],
      "env": {
        "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}

Then in Windsurf: Settings → Cascade → MCP — verify "preflight" appears.

VS Code (Copilot / Cline / Continue)

Add to .vscode/mcp.json in your project:

{
  "servers": {
    "preflight": {
      "command": "npx",
      "args": ["preflight-ios-mcp"],
      "env": {
        "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}

For Cline (VS Code extension), add to ~/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json:

{
  "mcpServers": {
    "preflight": {
      "command": "npx",
      "args": ["preflight-ios-mcp"],
      "env": {
        "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}

Zed

Add to ~/.config/zed/settings.json:

{
  "context_servers": {
    "preflight": {
      "command": {
        "path": "npx",
        "args": ["preflight-ios-mcp"],
        "env": {
          "PATH": "/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin"
        }
      }
    }
  }
}

Any MCP-Compatible Client

Preflight uses the standard MCP stdio transport. Configure your client to run:

npx preflight-ios-mcp

Set the PATH environment variable to include idb's location for cursor-free touch injection.

Tools Reference

Observation (6 tools)

| Tool | Description | |------|-------------| | simulator_screenshot | Take a JPEG screenshot optimized for AI chat (~200-400KB). Returns image inline. | | simulator_list_devices | List simulators with name, UDID, state, runtime. Filter: booted, available, all. | | simulator_list_apps | List installed apps with bundle IDs. Toggle includeSystem for system apps. | | simulator_app_info | Get app metadata: name, version, bundle path, data path, type. | | simulator_get_clipboard | Read the simulator's clipboard text. | | simulator_get_screen_info | Window geometry, coordinate mapping, scale factor. Debug tap accuracy. |

User Interaction (6 tools)

| Tool | Description | |------|-------------| | simulator_tap | Tap at (x, y) in simulator screen points. Cursor-free via idb. | | simulator_swipe | Swipe between two points. Supports edge-swipe-back from x=1. | | simulator_long_press | Long press with configurable duration. Context menus, drag initiation. | | simulator_type_text | Type text into the focused field. | | simulator_press_key | Press special keys (return, escape, arrows, F-keys) with modifiers. | | simulator_navigate_back | Navigate back via Cmd+[. Workaround for edge-swipe limitations. |

Playwright-Inspired (3 tools)

| Tool | Description | |------|-------------| | simulator_snapshot | Preferred over screenshots. Structured accessibility tree — roles, labels, values, positions. No vision model needed. Like Playwright's browser_snapshot. | | simulator_wait_for_element | Wait for an element to appear (by label, role, or text). Polls with configurable timeout. Like Playwright's browser_wait_for. | | simulator_element_exists | Quick boolean check: does an element matching criteria exist on screen right now? |

Device Management (6 tools)

| Tool | Description | |------|-------------| | simulator_boot | Boot a device by name or UDID. Optional waitForBoot polling. | | simulator_shutdown | Shut down a running simulator. | | simulator_erase | Factory reset — erases all content and settings. | | simulator_open_url | Open URLs or deep links (e.g., myapp://screen). | | simulator_open_simulator | Open the Simulator.app application. | | simulator_get_booted_sim_id | Get the UDID of the currently booted simulator. |

App Management (4 tools)

| Tool | Description | |------|-------------| | simulator_launch_app | Launch by bundle ID with optional args and env vars. | | simulator_terminate_app | Force-terminate a running app. | | simulator_install_app | Install a .app bundle or .ipa from a local path. | | simulator_uninstall_app | Uninstall by bundle ID. |

Debugging & Diagnostics (9 tools)

| Tool | Description | |------|-------------| | simulator_get_logs | Query device logs. Filter by process, subsystem, level, time range, message content. | | simulator_stream_logs | Live log streaming with start/read/stop lifecycle. Configurable buffer. | | simulator_get_app_container | Get filesystem path to app's bundle, data, or shared group container. | | simulator_list_app_files | Browse an app's Documents/, Library/, Caches/, tmp/ directories. | | simulator_read_app_file | Read plists (→JSON), SQLite (→schema), and text files from app data. | | simulator_get_crash_logs | Retrieve crash reports with stack traces and thread states. | | simulator_diagnose | Xcode version, disk usage, booted devices, system info. | | simulator_accessibility_audit | Full iOS accessibility tree — real UIButton/UILabel elements with labels, frames, roles. | | simulator_describe_point | Returns the accessibility element at given coordinates. |

System Simulation (5 tools)

| Tool | Description | |------|-------------| | simulator_set_location | Set GPS coordinates (lat/lng). Test location-based features. | | simulator_send_push | Send push notifications with full APNs payload JSON. | | simulator_set_clipboard | Set the simulator clipboard text. | | simulator_add_media | Add photos/videos to the camera roll from local files. | | simulator_grant_permission | Grant, revoke, or reset permissions (camera, location, photos, contacts, microphone, etc.). |

UI Configuration (4 tools)

| Tool | Description | |------|-------------| | simulator_set_appearance | Switch between light and dark mode. | | simulator_override_status_bar | Set time, battery, signal, carrier, network type. | | simulator_record_video | Start screen recording. On stop, key frames are extracted as images for AI chat. | | simulator_stop_recording | Stop recording. Returns key frames inline (no disk clutter). Optional savePath to keep the video. |

Advanced Debugging & Testing (18 tools)

| Tool | Description | |------|-------------| | simulator_set_content_size | Set Dynamic Type preferred size (13 categories from extra-small to accessibility-XXXL). | | simulator_set_increase_contrast | Toggle Increase Contrast accessibility setting. | | simulator_location_scenario | Run predefined GPS routes: Freeway Drive, City Run, City Bicycle Ride. | | simulator_location_route | Simulate movement along custom waypoints with configurable speed. | | simulator_memory_warning | Trigger simulated memory warning (didReceiveMemoryWarning). | | simulator_keychain | Add root certificates, add certificates, or reset the device keychain. | | simulator_icloud_sync | Trigger iCloud synchronization on the device. | | simulator_verbose_logging | Enable/disable verbose device logging for deep debugging. | | simulator_install_app_data | Install .xcappdata packages to restore test data snapshots. | | simulator_get_env | Read environment variables from the running simulator. | | simulator_biometric | Enroll, unenroll, match, or fail Face ID / Touch ID for auth testing. | | simulator_network_status | Get network configuration — DNS, interfaces, connectivity status. | | simulator_defaults_read | Read UserDefaults from inside the simulator (inspect app prefs, feature flags). | | simulator_defaults_write | Write UserDefaults inside the simulator (set flags, inject test config). | | simulator_rotate | Rotate the simulator left or right. | | simulator_notify_post | Post a Darwin notification to trigger system events. | | simulator_set_locale | Set device locale for internationalization testing. | | simulator_trigger_siri | Invoke Siri for voice command testing. |

Accessibility Settings (4 tools)

| Tool | Description | |------|-------------| | simulator_set_reduce_motion | Toggle Reduce Motion accessibility setting (via defaults write + notification). | | simulator_set_smart_invert | Toggle Smart Invert Colors (via defaults write + notification). | | simulator_set_bold_text | Toggle Bold Text (via defaults write + notification). | | simulator_set_reduce_transparency | Toggle Reduce Transparency (via defaults write + notification). |

Device Creation & Management (4 tools)

| Tool | Description | |------|-------------| | simulator_create_device | Create a new simulator with device type and runtime. | | simulator_delete_device | Permanently delete a simulator device. | | simulator_rename_device | Rename an existing device. | | simulator_clone_device | Clone a device with all its state. |

StoreKit Testing (6 tools) — Xcode 14-16

| Tool | Description | |------|-------------| | simulator_storekit_config | Enable or disable StoreKit test mode. | | simulator_storekit_transactions | List all StoreKit test transactions. | | simulator_storekit_delete_transactions | Clear all test transactions. | | simulator_storekit_manage_subscription | Expire or force-renew a subscription. | | simulator_storekit_manage_transaction | Refund, approve, or decline ask-to-buy transactions. | | simulator_storekit_reset_eligibility | Reset introductory offer eligibility for all products. |

Network Testing (2 tools)

| Tool | Description | |------|-------------| | simulator_network_condition | Apply network throttling with presets (3G, LTE, Edge, WiFi, 100% loss) or custom bandwidth/latency/loss. | | simulator_network_capture | Capture network activity summary — active connections, DNS, interfaces. |

Debugging & Profiling (5 tools)

| Tool | Description | |------|-------------| | simulator_leak_check | Check a running app for memory leaks via Apple's leaks tool. | | simulator_heap_info | Dump heap allocation summary — object counts by class, total memory. | | simulator_vmmap | Show virtual memory map — regions, sizes, permissions. | | simulator_sample_process | Sample a process for CPU hotspot detection and hang analysis. | | simulator_thermal_state | Simulate thermal pressure state changes (nominal, fair, serious, critical). |

Architecture

src/
├── index.ts                    # MCP server entry, 82 tool registrations
├── helpers/
│   ├── idb.ts                  # Facebook idb CLI wrapper (cursor-free touch)
│   ├── simctl.ts               # xcrun simctl command wrapper
│   ├── applescript.ts          # Keyboard input + CGEvent fallback
│   ├── coordinate-mapper.ts    # Simulator points → macOS screen coords
│   ├── mouse-events.swift      # Native Swift CGEvent binary (fallback)
│   └── logger.ts               # Structured stderr logging
└── tools/
    ├── screenshot.ts           # JPEG capture optimized for AI chat
    ├── interaction.ts          # Tap, swipe, long press, type, key
    ├── device.ts               # Boot, shutdown, erase, open URL
    ├── app.ts                  # Install, launch, terminate, list
    ├── system.ts               # Location, push, clipboard, media, permissions
    ├── ui.ts                   # Appearance, status bar, video recording, navigate back
    ├── debug.ts                # Logs, files, crash reports, accessibility
    ├── advanced.ts             # Dynamic Type, keychain, iCloud, biometric, defaults, accessibility, rotation, locale
    ├── storekit.ts             # StoreKit testing — transactions, subscriptions, eligibility
    ├── network.ts              # Network conditioning (dnctl/pfctl) and capture
    ├── profiling.ts            # Memory profiling — leaks, heap, vmmap, sample, thermal
    └── playwright.ts           # Snapshot, wait_for_element, element_exists

Design Philosophy

Accessibility-first, like Playwright MCP:

1. Use simulator_snapshot to understand the screen (structured text, no vision model)
2. Use coordinates from the snapshot to simulator_tap, simulator_swipe, etc.
3. Use simulator_screenshot when you need visual verification
4. Use simulator_wait_for_element before interacting with elements that appear after transitions

No disk clutter:

• Screenshots return as base64 in chat — no folders filling up your Desktop
• Video recordings extract key frames as inline images on stop
• Optional savePath parameter if you actually need files on disk

Touch Injection Pipeline

simulator_tap(x=200, y=400)
    │
    ├─ idb available? ──YES──► idb ui tap --udid <UDID> 200 400
    │                           (IndigoHID → real iOS touch event)
    │                           (zero cursor movement)
    │
    └─ idb unavailable? ──► coordinate mapper → macOS screen coords
                             → Swift CGEvent binary → mouse down/up

Demo App

A SwiftUI demo app is included in demo-app/ for testing all MCP features:

cd demo-app
xcodebuild -project MCPDemo.xcodeproj -scheme MCPDemo \
  -destination 'platform=iOS Simulator,name=iPhone 16 Pro' \
  build

The demo app has 7 tabs exercising every tool category:

• Interactions: Buttons, text fields, long-press zones, navigation stack, scrollable lists
• Location: Live GPS display for testing simulator_set_location
• Notifications: Push notification display for testing simulator_send_push
• Settings: Clipboard, file I/O, accessibility toggles, UserDefaults
• StoreKit: Mock purchases and subscriptions for testing StoreKit tools
• Network: Connection monitoring and latency testing for network conditioning
• Debug: Memory/CPU stress tests, thermal state, accessibility settings observer, biometric auth

Configuration

Environment Variables

| Variable | Default | Description | |----------|---------|-------------| | LOG_LEVEL | info | Logging level: debug, info, warn, error | | PREFLIGHT_FILTERED_TOOLS | (none) | Comma-separated list of tool names to disable | | PREFLIGHT_IDB_PATH | (auto-detect) | Custom path to idb binary | | PATH | System PATH | Must include idb binary location |

Example Prompts

QA Testing

"Boot the iPhone 16 Pro simulator, install my app at ./build/MyApp.app, launch it, and take a screenshot of the home screen. Then tap the login button, type [email protected] in the email field, and verify the form validation works."

Accessibility-First Workflow (Playwright-style)

"Take a snapshot of the current screen to see what elements are available. Then tap the button labeled 'Sign In' and wait for the email text field to appear."

Debugging

"My app is crashing on launch. Check the crash logs for MyApp, then get the last 5 minutes of device logs filtered to the MyApp process."

Dark Mode Testing

"Switch to dark mode, take a screenshot, then switch to light mode and screenshot again."

Troubleshooting

idb not detected

If tools show [CGEvent fallback] instead of [cursor-free]:

1. Verify idb is installed: which idb or check ~/Library/Python/3.x/bin/idb
2. Add the idb path to your MCP config's PATH env var
3. Or set PREFLIGHT_IDB_PATH directly

Simulator not found

1. Open Simulator.app: open -a Simulator
2. Boot a device: use simulator_boot or xcrun simctl boot "iPhone 16 Pro"

Accessibility permission errors

1. Go to System Settings → Privacy & Security → Accessibility
2. Add your terminal app (Terminal.app, iTerm, Claude Code, Cursor, Windsurf, etc.)

Development

npm run dev    # Watch mode (TypeScript only)
npm run build  # Full rebuild (TypeScript + Swift binary)
node dist/index.js  # Run directly

License

MIT License — see LICENSE for details.