mcp-server-withings

MCP server for the Withings Health API with per-user OAuth2 — each user links their own Withings account and can only ever see their own health data.

How isolation works

Behind an authenticating gateway that forwards the signed-in user as X-MCP-User, every tool is bound to that user. The server keeps an AES-256-GCM encrypted, per-user token store; a user's identity resolves only to their own row. Without a verified identity the server fails closed (no anonymous/shared access). Each user enrolls once via withings_connect, which returns a single-use Withings authorization URL bound to them; after they approve in the browser, /withings/callback stores their (encrypted) tokens.

Related MCP server: fitbit-mcp

Tools

Auth/enrollment: withings_connect, withings_status, withings_disconnect. Read: withings_get_measures, withings_get_activity, withings_get_sleep, withings_get_workouts, withings_get_heart, withings_get_devices, withings_get_goals, withings_search_capabilities. Write (opt-in WITHINGS_ENABLE_WRITES=true): withings_add_measure.

Configuration

See .env.example. Register a Withings app at account.withings.com; the redirect URI must match WITHINGS_REDIRECT_URI exactly and be publicly reachable (route /withings/callback to this container). Set WITHINGS_ENCRYPTION_KEY (never commit) and WITHINGS_TRUST_FORWARDED_USER=true behind the gateway.

Run

npm install
npm run dev:http     # /mcp + /withings/callback on :3000
npm test

Docker images: ghcr.io/borgels/mcp-server-withings.