Multi Calendar
Your Outlook.com, Microsoft 365, Google, iCloud and other calendars, in one connector.
Free time across all of them, events, booking pages, circles and group polls.
Add it to
- 1Add to ClaudeOpens claude.ai - press Connect there.
- 2
Sign in, add your calendar and approve Claude in the window Claude opens
- 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, add your calendar and approve Claude Code on the Lumman page your browser opens. 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, add your calendar and approve on the Lumman page it opens. In a chat, type @ and choose Multi Calendar.
- 1
Add to
~/.cursor/mcp.json - 2
Sign in, add your calendar and approve Cursor on the Lumman page Cursor opens
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.
Your calendars
Each calendar account has its own permissions - you tick what your AI app may do in it.
The words of every event are screened for prompt attacks before they reach your AI app, and the words of everything it writes before they reach your calendar's provider.
We keep no copy of your calendars. Events are read from Microsoft, Google, Apple or the calendar's own server each time they are needed. Privacy Policy
Made by Lumman Ltd, a publisher verified by Microsoft.
A circle sees only its members' busy times - never what their events say.
Guests book on your own booking page, with no account of their own.
Your calendar accounts
Your AI app
Price
- Free
Every calendar
1 booking page and 1 circle. No card.
- Plan
Any number of booking pages and circles
$50 a year or $5 a month
Switch from monthly to yearly at any time. Cancel any time - the paid period runs to its end.
Address
Claude's listing and the Claude Code plugin use https://calendar.lumman.co/mcp; https://lumman.co/mcp/calendar answers too.
Connection
- Transport
- Streamable HTTP
- Sign-in
- OAuth 2.1 with dynamic client registration. No key or client id.
- PKCE
- S256 only - a request bound with plain is refused
- A request
- Lasts 10 minutes - connect again from the app for a fresh one
- Discovery
- https://calendar.lumman.co/.well-known/oauth-protected-resource/mcp
- Removing an app
- Stops its next call
Limits
- Actions
- Up to 1,000 in any 24 hours, free or on the plan; refused and failed calls do not count
- Free
- Every calendar, 1 booking page, 1 circle
- Plan
- Any number of booking pages and circles
- Time zone
- The one stored for you, from your device; a call that gives times is refused while none is stored
- Booking pages
- Up to 120 requests a minute to the calendar account they ask most, across all of them; past that, guests are asked to try again shortly
- Page address
- 3 to 40 lowercase letters, digits or hyphens
- Circles
- Up to 50 addresses in one invitation
Your data
- Calendars
- No copy kept - read from Microsoft, Google, Apple or the calendar's own server each time they are needed
- Screening
- Words of every event screened by Google Cloud Model Armor, and of every write before it reaches the provider; a screening that cannot answer closes the call.
- Credentials
- Encrypted under a key held outside the database
- Busy blocks
- Private events titled Busy, naming the account they come from - on iCloud, which keeps no private events, and other CalDAV calendars, which may keep none, naming none - kept current by Lumman
- Links and polls
- Keep their meeting's name, length and times; a poll keeps its addresses and answers until it is booked or closed, 14 days at most
- Activity record
- What each call did, in which calendar account and how it ended - never what an event says
Tools
21Each account's permissions - See events, Change events, Invite and reply - decide which of these reach it.
Reading · 4
calendars_listList calendarsevents_listRead eventsevents_getRead an eventfree_times_findFind a timeEvents · 4
events_createCreate an eventevents_editChange an eventevents_cancelCancel an eventevents_respondAnswer an invitationPreferences · 3
preferences_getRead scheduling preferencespreferences_setChange scheduling preferencesbusy_everywhere_setShow busy time everywhereLinks, pages and polls · 7
booking_links_createMake a booking linkbooking_page_setSet up a booking pagepolls_createMake a group pollpolls_resultsRead a poll's answerspolls_bookBook a poll's timelinks_polls_listList open links and pollslinks_polls_closeClose a link or pollCircles · 3
circles_inviteInvite people into a circlecircles_listList circlescircles_free_times_findFind a time for a circleSource
- Repository
- github.com/lumman-lab/multi-calendar
- MCP registry
- co.lumman/calendar
- This page as text
- lumman.co/mcp/multi-calendar.md
- For AI agents
- lumman.co/llms.txt