Caltrain MCP

A remote MCP server that tells you exactly when the next Caltrain leaves, so you can be precisely informed about how late it is. It runs on Caltrain's official GTFS schedule, which means the disappointment is official too.

Server: https://caltrain-mcp-rho.vercel.app/mcp (Streamable HTTP, no auth). Live demo at caltrain-mcp-rho.vercel.app.

In ChatGPT and other MCP Apps hosts, answers come with an interactive timetable. Tap a train for its stops, or open the whole day with Express / Limited / Local filters and keep asking questions about what's on screen. Everywhere else you get the same answer as text.

What it knows

• The next trains between two stations, or the last ones that still get you there by 9.
• That the 12:05 AM train belongs to yesterday, that Thanksgiving runs a weekend schedule, and that South County doesn't do weekends.
• Where to change trains when there's no direct one.
• That sf, sj and 22nd are stations, because nobody types "San Francisco Caltrain Station".

Tools: next_trains, list_stations, and get_timetable (only the timetable view calls that one). All read-only.

Development

npm install
npm run dev    # http://localhost:3000, MCP at /mcp
npm test

It's Next.js on Vercel:

• Schedule engine: lib/schedule.ts.
• Timetable view: widget/, React, Tailwind and shadcn built into one HTML file.
• Feed: data/gtfs/. A weekly GitHub Action fetches a fresh one and opens a PR, and merging deploys it.

When the view changes, bump TIMETABLE_URI in lib/mcp/constants.ts. ChatGPT caches it harder than you'd think.

The old Python package on PyPI (uvx caltrain-mcp) still installs, but it's retired. Use the URL above.

License

LICENSE.md. Uses official Caltrain GTFS data; not affiliated with Caltrain. If the train is late, take it up with them.