Google Calendar in Claude and ChatGPT: several accounts, free time across all, and writing

Fezola connects several Google Calendar accounts to Claude and ChatGPT with one connector: the assistant lists events from all of them at once, finds a slot that is free in every calendar, and can create, move and delete events. Guests are not emailed unless the assistant explicitly asks for it. ChatGPT accepts custom MCP servers on Business and Enterprise/Edu plans (Pro read-only), so Claude is the easiest way in. The short version is on the Google Calendar connector page.

What the assistant can do

From Fezola's tools, as read in the code:

• list_calendar_events: events between two dates (the next 7 days by default) from every connected Google Calendar account at once, including shared and created calendars, with optional text search. Each event shows its account, calendar, title, times, location, organizer, attendee count, your response and meeting link.
• find_free_time: free slots of a chosen length, during working hours (09:00 to 18:00 by default, weekends skipped unless you ask), that are free in every connected account. This is the useful one when you have a personal and a work calendar.
• create_calendar_event: create an event in a chosen account and calendar.
• update_calendar_event: change the title, times, description, location or guests of an event.
• delete_calendar_event: delete an event. It goes to the calendar's trash, where you can restore it for 30 days.

What you can ask

• "What do I have tomorrow across my personal and work calendars?"
• "Find 45 minutes this week that is free on all my calendars."
• "Move my 3 pm call with Martin to Thursday morning, without notifying anyone yet."
• "Create a one-hour block named Review on Friday at 10 in my work calendar."

Invitations only when asked

Sending an invitation is sending an email in your name, so Fezola keeps it explicit. By default, guests are added to an event without any email. Invitations, change notices and cancellations go out only when the assistant sets notifyAttendees to true. Two habits help: ask the assistant to say whether it will notify guests, and keep your assistant's approval prompts on for writing tools, which are marked destructive.

Setup

1. Connect Google Calendar in Fezola. Create a free account, then Sources, Add source, Google Calendar, and sign in with each Google account, granting write access if you want the assistant to create and edit events. Add other accounts the same way.
2. Add Fezola to Claude with https://api.fezola.com/mcp: see how to add a custom connector to Claude. In ChatGPT, see how to add an MCP server to ChatGPT.
3. Ask, for example: "List my calendars' events for this week."

If you connected an account read-only, writing fails with a clear message and you reconnect it with write access.

Safety

• Event text is untrusted. An event title or description can be written by someone who invited you. Fezola's server instructions tell the assistant to treat calendar event descriptions as untrusted data rather than instructions, and to point out text that reads like an instruction.
• Limit what each assistant sees. You can leave tools unticked for an assistant, for example giving one only your calendar: see choose which tools Claude or ChatGPT can see.
• Revoke any time by disconnecting the Google account in Fezola.

Calendar next to the rest

The same connector also reads your mailboxes, Google Chat and Telegram, and works with Notion and Google Ads. Claude and ChatGPT also have their own Google Calendar connectors: Fezola's point is several Google accounts in one connector, with free time computed across all of them.