Callendar for ChatGPT

co.callendar/mcp

WhatsApp® reminders and rescheduling for Calendly. Public read-only MCP endpoint.

client:ChatGPT transport:streamable-http

Install Callendar in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://app.callendar.de/mcp

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