mcp-switchboard-hub

The server half of mcp-switchboard.

It accepts outbound WebSocket tunnels from machines running local stdio MCP servers, speaks MCP to each tunnelled server, and re-serves every tool from one place:

• /mcp — Streamable HTTP MCP endpoint for consumers (n8n, agents), also available scoped per machine (/mcp/host/{label}) or per server (/mcp/host/{label}/server/{server}).
• / — a web console to browse connections, servers and tools, call any tool by hand, and read back every call.
• /api/* — the JSON API behind the console.
• /metrics — Prometheus.
• Loki export and a SQLite call log.

Running

pip install mcp-switchboard-hub
MCP_SWITCHBOARD_TUNNEL_TOKEN=... mcp-switchboard-hub

It listens on two ports on purpose: the tunnel endpoint (default 127.0.0.1:8097) is the only thing meant to face the internet and always requires a bearer token, while the console, API, /mcp and /metrics live on a second listener (default 127.0.0.1:8099) that binds loopback and is unauthenticated by default.

Everything is configured through MCP_SWITCHBOARD_* environment variables, read from the environment or a .env file. Any value that starts with / and points at an existing regular file is replaced by that file's contents, so secrets can be passed as paths without separate *_FILE variables.

See the main README for the full picture, and docs/PROTOCOL.md for the tunnel wire format.