Prepare an event on the user’s calendar, inviting any listed attendees through Google Calendar. In Macro chat this tool opens an inline composer so the user can review, edit, and confirm the event; use the tool to present the proposal instead of asking for a redundant confirmation in prose. When the pending call is executed, the event is written to Google immediately and attendees receive invitations. Other clients should confirm attendee events before executing the call. The event lands on the user’s primary calendar unless calendarId (from ListCalendars) targets another one. For recurring events pass RFC 5545 lines in recurrenceLines, e.g. [“RRULE:FREQ=WEEKLY;BYDAY=MO”]. Returns the created event with its eventId for later updates or deletion. Fails if the user has no writable calendar connected.