MCP Command Proxy

An MCP (Model Context Protocol) server that acts as a proxy for CLI commands, specifically designed for Expo development but adaptable for any command-line application.

How to use in Cursor (Expo example)

1. Go to the directory of your Expo project

2. Run npx mcp-command-proxy --prefix "ExpoServer" --command "expo start" --port 8383

3. Go to Cursor settings -> MCP -> +Add new MCP server, like this:
   

4. Set the name to "ExpoServer", Type to "SSE", URL to http://localhost:8383/sse

5. Click "Save" and you should now be able to use the MCP server in Cursor. Like this:

Recommended to use the --port 8383 flag to avoid conflicts with other servers. Also, you can add following instruction to .cursorrules file:

Related MCP server: OpenAPI to Model Context Protocol (MCP)

Features

• Command Proxying: Run any CLI command through the MCP server

• Log Collection: Capture and store logs from running processes (configurable buffer size)

• Key Press Forwarding: Forward key presses from client to the running process

• Transparent Experience: The end user sees the command output exactly as if they ran it directly

• Interactive Commands: Works with interactive CLI tools like Expo

• MCP Integration: Built using the MCP SDK for easy integration with Claude and other MCP-enabled AI assistants

How It Works

1. The server starts a specified command in a pseudo-terminal (PTY)

2. All stdout/stderr output is:

   • Streamed to the client in real-time

   • Stored in a circular buffer (configurable size, default 300 lines)

3. Key presses from the client are forwarded to the running process

4. The server provides tools to:

   • View collected logs

   • Send key presses to the process

   • Get the current state of the process

Use Cases

• Expo Development: Run expo start and interact with it while collecting logs

• Build Processes: Monitor build processes and analyze logs

• Long-running Services: Monitor services and keep recent log history

• Remote Command Execution: Execute and monitor commands from remote clients

Requirements

• Node.js 18+

• TypeScript

• pnpm (recommended) or npm

Installation

Usage

Basic Usage

Options

• --prefix, -p: Name/prefix for the server (default: "CommandProxy")

• --command, -c: Command to run (required)

• --buffer-size, -b: Number of log lines to keep in memory (default: 300)

• --port: Port for HTTP server (default: 8080)

• --help, -h: Show help

MCP Integration

This server implements the following MCP tools:

1. getRecentLogs: Returns the most recent logs from the buffer

   • Parameters:

     • limit (optional): Number of logs to return (default: 100)

     • types (optional): Types of logs to include (stdout, stderr, system) (default: all)

2. sendKeyPress: Sends a key press to the running process

   • Parameters:

     • key: Key to send (e.g. "enter", "a", "1", "space")

3. getProcessStatus: Returns the current status of the process

   • Parameters: None

Examples

Running Expo Start

Using with Claude

1. Configure Claude to connect to this MCP server (SSE endpoint: http://localhost:8080/sse)

2. Ask Claude to run Expo or other commands

3. Claude can analyze logs and help troubleshoot issues

Development

License

MIT