Holiday Calendar for ChatGPT

com.modernmustardseed/holiday-calendar

U.S. federal holidays with observed dates and business-day math. Example from an open-source kit.

client:ChatGPT transport:streamable-http tools:5

Install Holiday Calendar in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://starter.modernmustardseed.com/holidays

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