mcp-bridge-claude-to-vscode

VSCode as MCP Relay

This is a Node.js implementation of an MCP (Mechanism, Control, Policy) relay for VSCode extensions. It's based on the Go implementation in ../mcp-relay/main.go but adds the following features:

Features

• Multiple Server Support: Scans ports from the specified port to +10 to discover and connect to multiple MCP Bridges.
• Custom Protocol Extensions: Implements custom protocol messages for:
  • Client notifying server: "You are now the main server"
  • Server requesting to client: "I want to be the main server"
• Fallback Capability: Can switch between available servers if the primary becomes unresponsive.

Installation

cd packages/relay
npm install -g

Usage

vscode-as-mcp-relay --server-url http://localhost:60100 --listen-port 6011

Command Line Options

• --server-url: Base URL of the MCP Bridge (default: http://localhost:60100)
• --listen-port: Starting port to listen for incoming JSON-RPC messages (default: 6011)

Custom Protocol

The relay implements a custom protocol for communication between clients and servers:

• Registration:

  {
    "clientUrl": "http://localhost:PORT",
    "features": ["relay_protocol_v1"]
  }
  

• Set Main Server (Client to Server):

  {
    "jsonrpc": "2.0",
    "method": "$relay",
    "params": {
      "type": "set_main",
      "clientPort": PORT
    }
  }
  

• Request to be Main (Server to Client):

  {
    "jsonrpc": "2.0",
    "method": "$relay",
    "params": {
      "type": "request_main",
      "serverUrl": "http://localhost:PORT"
    }
  }
  

How It Works

• The relay scans ports to discover available MCP Bridges.
• It registers with all discovered servers.
• It establishes the first discovered server as the primary.
• It processes stdin and relays messages to the active server.
• If a server requests to be the main server, the relay can switch its active connection.
• If the active server becomes unresponsive, the relay can fail over to another server.