reference data mcp server for ChatGPT

io.github.cyanheads/reference-data-mcp-server

Countries, timezones, elements, constants, HTTP status codes, unit conversion, and MIME type lookup.

client:ChatGPT transport:streamable-http runtime:npm tools:10

Install reference data mcp server in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://reference-data.caseyjhand.com/mcp

Custom connectors are a paid-plan feature and take a remote URL only. ChatGPT cannot run a packaged server locally. ChatGPT docs