mcp-server-proxy

A Node.js library for proxying and merging Model Context Protocol (MCP) servers.

Installation

npm install mcp-server-proxy

Features

• Proxy MCP server requests to another MCP server
• Merge multiple MCP servers into a single endpoint
• Automatically register tools, resources, and prompts from source servers

Usage

Basic Example

import { proxyMcp } from 'mcp-server-proxy';
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { SSEClientTransport } from "@modelcontextprotocol/sdk/client/sse.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";

async function main() {
    // Create a new MCP server
    const server = new McpServer({
        name: "mcp-proxy-server",
        version: "1.0.0",
    })

    // Add mcp sse url to proxy
    const sseClientTransport = new SSEClientTransport(new URL("http://your-mcp-sse-url/sse"))
    await proxyMcp(server, sseClientTransport)

    // Add stdio mcp server to proxy
    const stdioClientTransport = new StdioClientTransport({
        command:"node",
        args: ["dist/example.js"],
    })
    await proxyMcp(server, stdioClientTransport)

    // Add streamable http mcp server to proxy
    const streamableHTTPClientTransport = new StreamableHTTPClientTransport(new URL("http://your-mcp-http-url"))
    await proxyMcp(server, streamableHTTPClientTransport)

    //  Start the proxy server example as a stdio transport
    const stdioServerTransport = new StdioServerTransport()
    server.connect(stdioServerTransport)
    console.error("MCP Proxy Server running on stdio");
}

main().catch(console.error);

API Reference

proxyMcp(mcpServer, proxyTransport, proxyOptions?)

Registers all tools, resources, and prompts from a source MCP server to your target MCP server.

• mcpServer: The target MCP server instance
• proxyTransport: ClientTransport to connect to the source MCP server
• proxyOptions: Optional request options for the connection

Returns: Promise resolving to the updated MCP server

License

MIT