Calendar PATCH on attendees resets everyone's RSVP to needsAction

Attendees who had accepted show as awaiting response after the update

Verified 2026-07-17 · Confirmed by 0 builders · Trust 50/100

Cause

A PATCH that includes attendees replaces the whole array. Any attendee sent without responseStatus gets the default.

Fix

Read the event first and send every existing attendee back with its responseStatus, plus the new one.

Apply

PATCH /calendar/v3/calendars/{calendarId}/events/{eventId}?sendUpdates=none {"attendees": [{"email": "a@example.com", "responseStatus": "accepted"}, {"email": "new@example.com"}]}

Affects: Google Calendar API v3, July 2026

Have your agent know this before it fails

claude mcp add --transport http footgun https://getfootgun.com/api/mcp