expo-mcp

Name: Expo MCP Server
Availability: InStock
Rating: 3.0 (1 reviews)

MCP server for Expo/React Native app automation with Maestro integration.

Features

Session-Based Architecture: Launch Expo and device binds automatically - no manual device ID management
Expo Dev Server Management: Start/stop/reload Expo development server
Maestro Integration: Full UI automation tools (tap, input, screenshot, etc.)

Installation

npm install -g expo-mcp
# or
npx expo-mcp

Usage with Claude Code

Add to your .mcp.json:

{
  "mcpServers": {
    "expo-mcp": {
      "command": "npx",
      "args": ["-y", "expo-mcp"],
      "env": {
        "EXPO_APP_DIR": "/path/to/your/expo/app"
      }
    }
  }
}

Quick Start

# 1. Start session (launches Expo + binds device automatically)
launch_expo({ target: "ios-simulator" })

# 2. Use Maestro tools directly (no device_id needed!)
take_screenshot()
tap_on({ text: "Login" })
input_text({ text: "hello@example.com" })

# 3. Reload app after code changes
reload_expo()

# 4. Check logs if needed
get_logs({ level: "error" })

# 5. Stop session when done
stop_expo()

Tools

Lifecycle Tools

Tool	Description
`app_status`	Get session status (server info, device_id)
`launch_expo`	Start Expo server and establish session with device
`stop_expo`	Stop Expo server and end session
`reload_expo`	Hot reload the app on connected device
`get_logs`	Get Metro bundler logs (filterable by level)

launch_expo Options

Option	Type	Description
`target`	`ios-simulator` \| `android-emulator` \| `web-browser`	Device to launch
`host`	`lan` \| `tunnel` \| `localhost`	Connection mode
`port`	number	Server port (default: 8081, auto-increments if busy)
`clear`	boolean	Clear Metro bundler cache
`dev`	boolean	Development mode (default: true)

Maestro Tools

All Maestro tools work automatically once a session is active:

Tool	Description
`tap_on`	Tap on UI element by text, id, or point
`input_text`	Type text into focused field
`take_screenshot`	Capture screen (auto-resized for LLM)
`inspect_view_hierarchy`	Get UI element tree
`launch_app`	Launch app by bundle ID
`back`	Press back button
`run_flow`	Run Maestro YAML flow

Note: Maestro tools require an active session. Call launch_expo first.

Environment Variables

Variable	Description	Default
`EXPO_APP_DIR`	Path to Expo app directory	Current working directory
`MAESTRO_CLI_PATH`	Path to Maestro CLI	`~/.maestro/bin/maestro`
`ESSENTIAL_TOOLS`	Comma-separated list of tools to expose	All tools
`LOG_BUFFER_SIZE`	Max log lines to keep in memory	400

How It Works

Session Creation: launch_expo starts Expo dev server and waits for device connection
Device Binding: Once device connects, its ID is stored in the session
Automatic Injection: All Maestro tools automatically use the session's device ID
Session End: stop_expo cleans up everything

This eliminates the need for manual device_id management.

Requirements

Node.js >= 18
Xcode (for iOS Simulator)
Android Studio (for Android Emulator)
Maestro CLI (for UI automation)

License

MIT

Expo MCP Server