FindSaunaPlunge MCP server

Model Context Protocol server for findsaunaplunge.com: cold plunge, sauna and contrast-therapy venues across US metros. get_data_freshness reports the current venue count and the dates the records were last checked. Every published temperature and price is read from the venue's own pages and carries its source URL, capture date and verbatim quote. Absent fields mean the venue does not publish that detail — never zero.

• Endpoint: https://findsaunaplunge.com/mcp — Streamable HTTP, stateless, no auth, open CORS. GET serves human documentation; POST is JSON-RPC.
• Registry: com.findsaunaplunge/findsaunaplunge (domain-verified).
• Data: same records as the CC BY 4.0 feed /api/v1/venues.json; archived monthly at github.com/findsaunaplunge/data, DOI 10.5281/zenodo.22132913.

Tools

Connect

# Claude Code
claude mcp add --transport http findsaunaplunge https://findsaunaplunge.com/mcp

# Any client, by hand
curl -s -X POST https://findsaunaplunge.com/mcp -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"search_venues","arguments":{"citySlug":"austin-tx","modality":"cold_plunge","limit":3}}}'

Run it yourself

The handler needs nothing but the public feed, so it runs anywhere with Node 24+:

npm start                    # JSON-RPC over stdio, one message per line (= node src/serve.ts --stdio)
npm run http                 # Streamable HTTP on :8080 — POST /mcp        (= node src/serve.ts)
docker build -t findsaunaplunge-mcp . && docker run -i findsaunaplunge-mcp   # stdio
npm test                     # smoke test: stdio + HTTP against the live feed

Both modes read https://findsaunaplunge.com/api/v1/venues.json (override with FINDSAUNAPLUNGE_ORIGIN), so a self-hosted copy serves exactly what the site serves.

How it runs

src/mcp.ts is the whole server: one handleMcp(request, env) function mounted at /mcp inside the site's Cloudflare Worker. It has no dependencies. Tool results come from the static /api/v1/venues.json asset produced by the site build (fetched through the Worker's ASSETS binding and memoized per isolate), so the server can never disagree with the site and a deploy refreshes it automatically. server.json is the registry manifest.

This repository is the published source of that server. The site itself is not open source.

Design rules

• Stateless: no sessions, no server-initiated SSE. Every POST is self-contained.
• Unknown arguments are rejected with a message naming the valid ones, rather than silently ignored.
• Nothing here is, or will be, a paid placement.

Licence

MIT — see LICENSE. The venue data the server serves is separately licensed CC BY 4.0.