Confirm or decline a Cal.com booking that requires host confirmation, or mark host/attendee absence after the meeting, via API v2.

Documented steps

1. Authenticate with Authorization: 'Bearer <token>' (API key, or OAuth token carrying the BOOKING_WRITE scope).
2. Identify the target bookingUid — typically one with status 'pending' (requires confirmation).
3. To confirm: POST https://api.cal.com/v2/bookings/{bookingUid}/confirm with header cal-api-version: 2026-02-25 and no required body.
4. To decline: POST https://api.cal.com/v2/bookings/{bookingUid}/decline with header cal-api-version: 2026-02-25 and an optional body field reason (string).
5. After confirm/decline, check the response status and data.status, which should read 'accepted' or 'rejected'.
6. To record absence after the meeting, POST https://api.cal.com/v2/bookings/{bookingUid}/mark-absent with header cal-api-version: 2026-02-25.
7. In the mark-absent body, optionally set host: true/false to flag the host as absent.
8. Optionally include an attendees array of objects, each with required email (string) and absent (boolean), to flag specific attendees.
9. Read data.absentHost and the per-attendee absence fields to confirm; recurring bookings also return recurringBookingUid.
10. Handle both standard and recurring booking output shapes in the response.
11. Docs: https://cal.com/docs/api-reference/v2/bookings/confirm-a-booking