MCP Local Router

What is MCP Local Router?

MCP Local Router is an aggregation proxy for MCP (Model Context Protocol) servers. It connects to multiple upstream MCP servers and combines their functionalities into a single interface for downstream clients.

How to use MCP Local Router?

Run the router with a JSON configuration file and specify the transport: cargo run -- --config mcp-config.json --transport stdio or --transport sse. The configuration file defines each upstream server with command, args, and env fields. For SSE transport, the router exposes aggregated (/sse) and per‑upstream (/sse/{serverName}) endpoints.

Key features of MCP Local Router

• Supports configuration file specified via command‑line argument.
• Configures multiple upstream MCP servers from one JSON file.
• Supports stdio transport with optional environment variable injection.
• Supports SSE transport with aggregated /sse and per‑upstream /sse/{serverName} endpoints.
• All SSE connections share a single POST /message?sessionId=… channel.

Use cases of MCP Local Router

• Aggregate several MCP servers (e.g., filesystem, database) into a single service.
• Route a client to a specific upstream server using the per‑upstream SSE path.
• Test or develop multiple MCP servers together without separate client wiring.
• Inject different environment variables per upstream server for credential isolation.