Connect Google Calendar to Claude and ChatGPT
Multi Calendar connects Google calendars to Claude and ChatGPT with Google sign-in, so Lumman never receives your password.
For Gmail and Google Workspace accounts.
The AI apps' own connectors
- Google Calendar, Google's own connector in Claude's directory, searches events, finds free time, creates and updates events and answers invitations. Read on 3 November 2026.
- ChatGPT's release notes say its Google Calendar plugin connects several Google accounts at once and checks their calendars together. Read on 3 November 2026.
Connect it
Add it to
- 1Add to ClaudeOpens claude.ai - press Connect there.
- 2
Sign in, choose Google Calendar and allow access at Google in the window Claude opens. That adds your calendar and approves Claude in one step.
- 3
Ask Claude about your week
- 1
Run in Claude Code
/plugin marketplace add lumman-lab/multi-calendar/plugin install multi-calendar@multi-calendarRun the first, then the second.
- 2
Sign in, choose Google Calendar and allow access at Google on the Lumman page your browser opens. That adds your calendar and approves Claude Code in one step. If none opens, run /mcp and choose multi-calendar.
- 3
Ask, or run
/multi-calendar:week
Works fully on ChatGPT Business, Enterprise and Edu.
- 1
Copy the address
- 2Open ChatGPT plugins
Press +, choose Add custom MCP server, name it Multi Calendar, paste the address, choose OAuth, tick the box and press Create as a plugin.
- 3
Install it, then sign in, choose Google Calendar and allow access at Google on the Lumman page it opens. That adds your calendar and approves ChatGPT in one step. In a chat, type @ and choose Multi Calendar.
- 1
Add to
~/.cursor/mcp.json - 2
Sign in, choose Google Calendar and allow access at Google on the Lumman page Cursor opens. That adds your calendar and approves Cursor in one step.
Streamable HTTP, OAuth 2.1 with dynamic client registration. No key or client id.
- VS Code
Run MCP: Add Server, choose HTTP, paste the address and name it multi-calendar.
- Gemini CLI
gemini extensions install https://github.com/lumman-lab/multi-calendarIts first call opens Lumman's sign-in; /mcp auth multi-calendar opens it again.
- Antigravity
agy plugin install https://github.com/lumman-lab/multi-calendarRun /mcp, open multi-calendar_multi-calendar and choose Authenticate; approve on the Lumman page, then paste the code Antigravity shows back into it.
Free for every calendar you connect. Any number of booking pages and circles for $50 a year or $5 a month.
Reach and limits
- Find free time across it and every other calendar you add.
- Create, move and cancel events, and answer invitations.
- Share booking links and a booking page, run group polls, and find a time with the people in a circle.
- A Gmail account makes no out of office or focus time. A Google Workspace account makes them in its main calendar, where its edition offers them.
If it refuses
- Google granted only part of what the connector needs, so nothing was connected. Connect the calendar again and leave every permission ticked.
Connection
- Reached through
- Google Calendar API
- Permissions
- openid, email, calendar.calendarlist.readonly, calendar.events
Your data
- Stored
- Google's credential, encrypted under a key held outside the database
- Calendars
- No copy kept - read from the calendar on each call
- Removing it
- Disconnecting withdraws Lumman's access at Google too.
Tools
- Offered
- All 21
Everything else
Multi Calendar's address, sign-in, limits and every tool: Multi Calendar's technical details.