tilwhen date engine for ChatGPT

com.tilwhen/tilwhen

Deterministic date arithmetic with auditable receipts: business days, due dates, holidays.

client:ChatGPT transport:streamable-http tools:9

Install tilwhen date engine in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://mcp.tilwhen.com/mcp

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