Lists the calendars on the user's calendar list: id (use it as calendar_id in every other tool), summary, description, timeZone (IANA), accessRole (owner/writer/reader/freeBusyReader — writes need writer or owner), primary:true on the main calendar, and hidden/selected flags. The special id "primary" always addresses the main calendar without listing first. Paginate with page_token from nextPageToken. Calendars shared with the user but never added to their list do not appear here — address them by their explicit id.

Fetches one calendar-list entry: summary, description, timeZone (the calendar's default IANA zone — use it to interpret event times), accessRole, defaultReminders and primary. Works only for calendars on the user's list; for a shared calendar never added to the list, use raw_request with path calendar/v3/calendars/ instead.

Lists events on a calendar: id, summary, start/end (all-day events carry date with an EXCLUSIVE end; timed events carry dateTime), status, attendees with responseStatus, organizer, recurrence, hangoutLink, eventType. time_min/time_max bound the window (an event overlapping the window is included). single_events=true expands recurring events into individual instances — required for order_by=start_time and the right choice for questions like "what is on my calendar this week"; without it recurring events appear once as the series master. time_zone only changes how times are RENDERED in the response, never the events themselves. q searches summary/description/location/attendees. updated_min + show_deleted enable incremental polling (cancelled events come back as status=cancelled). Paginate with page_token from nextPageToken.

Fetches one event by id: summary, description, location, start/end, attendees with their responseStatus (accepted/declined/tentative/needsAction), organizer, recurrence rules, recurringEventId (present on instances of a series), conferenceData/hangoutLink (Google Meet), reminders, visibility, transparency and eventType. Works for a series master and for an individual instance id alike.

Creates an event and returns it (id, htmlLink, start/end, attendees, hangoutLink when add_meet). Times: EITHER start_date_time + end_date_time (RFC3339; add time_zone for recurring events) OR start_date + end_date for all-day (end_date is EXCLUSIVE — the day after the last day). recurrence makes it a recurring series. attendees invites guests — but the API sends invitation emails ONLY with send_updates=all (the default notifies nobody). add_meet attaches a Google Meet link (may come back status=pending — re-run get_event for the final URL). This is a plain calendar write: it does not check for conflicts — call query_free_busy first to find a free slot. Never blindly re-send after a timeout or 5xx: the event may already exist — check with list_events first, or you will create a duplicate and re-invite everyone.

Partially updates an event (PATCH): only the provided fields change, but a provided nested object REPLACES its predecessor wholesale — attendees replaces the entire guest list (get_event first, send the complete new list), reminders replaces all overrides, and a time change should carry BOTH the new start and end (start_date_time + end_date_time, or start_date + end_date). To reschedule one occurrence of a recurring series, pass that instance's id (from list_event_instances) as event_id; passing the series master id changes every occurrence. Guests hear about the change only with send_updates=all. Also works to update Out of Office / Focus Time blocks. Returns the updated event.

Deletes (cancels) an event — there is no undelete. Deleting a series master id cancels the ENTIRE recurring series; deleting one instance id (from list_event_instances) cancels only that occurrence. On an event with guests this cancels the meeting for everyone, but cancellation emails go out only with send_updates=all. Returns {deleted:true}.

Moves an event to a different calendar (changes its organizer calendar; the event id stays the same). Rescheduling to another TIME is update_event, not this. Only regular events can move — Out of Office, Focus Time, working-location and birthday events cannot, and events with attendees can be moved only by their organizer. Needs writer access to both calendars. send_updates=all notifies the guests.

Expands one recurring event (the series master id) into its individual instances, each with its own id (like masterId_20260901T100000Z) and concrete start/end. Use an instance id with update_event to reschedule a single occurrence, or with delete_event to cancel just that one; exceptions already made to the series show their changed times here. show_deleted=true includes cancelled occurrences. Bound the window with time_min/time_max — an unbounded infinite series is paginated via page_token.

Returns the busy intervals of up to 50 calendars in one time window — the way to find a common free slot before create_event. Input calendar ids (or attendee email addresses, which double as their primary-calendar ids — subject to their sharing settings). The response maps each calendar id to busy:[{start,end}] ranges; gaps between them are free. Only busy blocks come back — never event titles or details — and events marked transparent (free) don't appear. A calendar the user cannot read shows up under errors, not busy. This is a pure read despite being an HTTP POST.

Creates an Out of Office event that can auto-decline meeting invitations while it lasts (auto_decline: all overlapping meetings, or only new invitations; decline_message customizes the reply). ONLY works on the PRIMARY calendar of a Google Workspace account — consumer Gmail and secondary calendars get HTTP 400. Always timed (start/end date_time), never all-day. Manage it afterwards like any event: update_event to change it, delete_event to remove it, list_events with event_types=["out_of_office"] to find existing blocks. Not retried after an ambiguous failure — check list_events before re-sending.

Creates a Focus Time event: blocks the slot, can auto-decline conflicting invitations (auto_decline + decline_message) and can flip Google Chat to Do Not Disturb (chat_status). ONLY works on the PRIMARY calendar of a Google Workspace account — consumer Gmail and secondary calendars get HTTP 400. Always timed (start/end date_time), never all-day. Manage it afterwards like any event: update_event / delete_event, and list_events with event_types=["focus_time"] to find existing blocks. Not retried after an ambiguous failure — check list_events before re-sending.

Escape hatch to call any Google Calendar API v3 path directly, for requests the typed tools don't cover — e.g. events.quickAdd ("calendar/v3/calendars/primary/events/quickAdd?text=Lunch tomorrow noon", POST), the colors palette ("calendar/v3/colors"), ACL rules, secondary-calendar creation ("calendar/v3/calendars", POST), removing a Meet conference (PATCH with {"conferenceData":null} and ?conferenceDataVersion=1), watch channels, or an event PUT that replaces every field. The path is relative to https://www.googleapis.com, must stay under calendar/v3/ (other Google APIs on this host — drive/v3, gmail/v1, ... — are rejected before any request is sent) and may carry a query string. The Bearer token is added automatically; the method defaults to GET. Remember: PUT replaces unspecified fields with defaults — prefer PATCH semantics via update_event when possible.