MCP Proxy Server

MCP Proxy Server

An MCP proxy server that aggregates and serves multiple MCP resource servers through a single interface. This server acts as a central hub that can:

• Connect to and manage multiple MCP resource servers
• Expose their combined capabilities through a unified interface
• Handle routing of requests to appropriate backend servers
• Aggregate responses from multiple sources

Features

Resource Management

• Discover and connect to multiple MCP resource servers
• Aggregate resources from all connected servers
• Maintain consistent URI schemes across servers
• Handle resource routing and resolution

Tool Aggregation

• Expose tools from all connected servers
• Route tool calls to appropriate backend servers
• Maintain tool state and handle responses

Prompt Handling

• Aggregate prompts from all connected servers
• Route prompt requests to appropriate backends
• Handle multi-server prompt responses

Configuration

The server requires a JSON configuration file that specifies the MCP servers to connect to. Copy the example config and modify it for your needs:

cp config.example.json config.json

Example config structure:

{
  "servers": [
    {
      "name": "Server 1",
      "transport": {
        "command": "/path/to/server1/build/index.js"
      }
    },
    {
      "name": "Server 2",
      "transport": {
        "command": "server2-command",
        "args": ["--option1", "value1"]
      }
    }
  ]
}

The config file must be provided when running the server:

MCP_CONFIG_PATH=./config.json mcp-proxy-server

Development

Install dependencies:

npm install

Build the server:

npm run build

For development with auto-rebuild:

npm run watch

Installation

To use with Claude Desktop, add the server config:

On MacOS: ~/Library/Application Support/Claude/claude_desktop_config.json On Windows: %APPDATA%/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "mcp-proxy": {
      "command": "/path/to/mcp-proxy-server/build/index.js",
      "env": {
        "MCP_CONFIG_PATH": "/absolute/path/to/your/config.json"
      }
    }
  }
}

Debugging

Since MCP servers communicate over stdio, debugging can be challenging. We recommend using the MCP Inspector, which is available as a package script:

npm run inspector

The Inspector will provide a URL to access debugging tools in your browser.