Supercharge Your JetBrains IDE with the MCP Proxy Server: A Comprehensive Guide

Tired of integration headaches between your JetBrains IDE and other tools like Claude Desktop, LibreChat, or Docker containers? The JetBrains MCP (Machine Code Proxy) server is your solution. This guide provides clear instructions and troubleshooting tips to get you up and running quickly, boosting your workflow and productivity.

What is the JetBrains MCP Proxy Server?

The JetBrains MCP proxy acts as a bridge, forwarding requests from external clients to your JetBrains IDE. It unlocks seamless communication and integration between your IDE and other applications, expanding your development ecosystem.

Installation: Get the MCP Server Plugin

1. Install the MCP Server plugin directly from the JetBrains Marketplace: https://plugins.jetbrains.com/plugin/26071-mcp-server
2. Restart your IDE to activate the plugin.

Integrate with Claude Desktop: A Step-by-Step Guide

Enhance your Claude Desktop experience with direct access to your JetBrains IDE. Here's how to configure it:

1. Locate your claude_desktop_config.json file:
   • MacOS: ~/Library/Application\ Support/Claude/claude_desktop_config.json
   • Windows: %APPDATA%/Claude/claude_desktop_config.json
2. Add the following configuration snippet to the claude_desktop_config.json file:

{
  "mcpServers": {
    "jetbrains": {
      "command": "npx",
      "args": ["-y", "@jetbrains/mcp-proxy"]
    }
  }
}

This configuration tells Claude Desktop how to communicate with the MCP proxy server.

Advanced Configuration: Fine-Tune Your Connection

Need more control? Customize your MCP server setup with these options:

• Connecting to a Specific IDE:

If running multiple IDEs, specify the port of the desired IDE's built-in webserver:

"env": {
  "IDE_PORT": "<port of IDE's built-in webserver>"
}

• Specifying a Host Address:

By default, the proxy connects to 127.0.0.1. To use a different address:

"env": {
  "HOST": "<host/address of IDE's built-in webserver>"
}

• Enabling Logging:

For debugging purposes, turn on logging:

"env": {
  "LOG_ENABLED": "true"
}

Troubleshooting Common Issues: Solutions to Keep You Going

Encountering problems? Here’s a rundown of common issues and their solutions:

• Node.js Version Woes

Problem: "Cannot find module 'node:path'" error.

Solution: The MCP Proxy requires Node.js version 18 or later. Upgrade your Node.js installation and ensure the configuration points to the correct version. Use the full path to the latest Node.js executable if necessary.

• MacOS: nvm and Plugin Detection

Problem: The plugin doesn't detect Node.js installed via nvm.

*Solution: Create a symbolic link:

which npx && sudo ln -sf "$(which npx)" /usr/local/bin/npx

This ensures the plugin can find the npx executable.

• External Clients, Docker, and 404 Errors

Problem: 404 errors or connection failures with external clients like LibreChat or Docker containers.

*Solution: This usually occurs when connecting from external clients to the JetBrains MCP proxy. Here’s the fix:

1.  **Enable External Connections:** In your IDE's settings (Build, Execution, Deployment | Debugger), enable "Can accept external connections."
2.  **LAN IP and Port Configuration:** Use your machine's LAN IP address instead of `host.docker.internal`.  Explicitly set `IDE_PORT` and `HOST` in your configuration.

Here’s an example configuration for LibreChat:

mcpServers:
  intellij:
    type: stdio
    command: sh
    args:
      - "-c"
      - "IDE_PORT=YOUR_IDEA_PORT HOST=YOUR_IDEA_LAN_IP npx -y @jetbrains/mcp-proxy"

Remember to replace YOUR_IDEA_PORT and YOUR_IDEA_LAN_IP with your actual values. Using the correct LAN IP and port will resolve connection issues with external clients accessing the MCP proxy.

Building the Project: A Developer's Guide

Want to contribute or customize the project? Follow these steps:

1. Prerequisites (macOS):
   • Install Node.js: brew install node
   • Install pnpm: brew install pnpm
2. Build: Run pnpm build in the project directory.