Checkout Trip

Checkout a trip, returns the web checkout_url a human opens to pay, plus the agent_spt_params an agent can use to pay programmatically (no browser).

PREREQUISITES (call these first via the trip tool):
  trip(add_item)         → add the chosen flight or hotel to the trip
  trip(upsert_travelers) → set traveler details + contact info

USAGE:
  checkout({ trip_id })

Jinko prices the trip (schedules a quote and waits until it completes) and returns checkout_url, a Jinko page where the traveller reviews the trip and pays, all in one synchronous call. Checkout books nothing and charges nothing: the booking starts only when the traveller pays at checkout_url or you call submit_agent_payment. Until then get_trip shows no fulfillment and no booking_ref, and trip.status reads "draft" ("expired" once the trip is left untouched for 24 hours).
  • Human path: open the returned checkout_url in a browser to pay. Stripe webhooks finalize the booking after payment succeeds; no client-side confirm step is required.
  • Agent path: mint a Shared Payment Token scoped to agent_spt_params, then call submit_agent_payment({ trip_id, shared_payment_token }).

OPTIONAL FLIGHT ANCILLARIES: checkout → trip(select_ancillaries) → checkout. The first checkout quotes the trip; use get_trip to inspect available_ancillaries, select with the user's approval, then checkout again to refresh the quote and payment artifacts. Pay only from the latest checkout response.

If travelers are edited after checkout, the quote is invalid: call checkout again before paying.

IMPORTANT: Never fabricate traveler data. Always make sure trip(add_item) and trip(upsert_travelers) have been called with real user-provided data first.