Submit the visitor's request on a form that collects requests for review: the quote's fields plus submission_id, a UUID the page generates once per submission and sends again on a retry. Saves one order for the business to review and dispatch; nothing is quoted, booked or dispatched. Idempotent per submission_id: a retry, a double click or a new session for the same form gets the same reference and never a second order. reference identifies the order.

VALIDATION_ERRORS (422) maps body paths (store_id, recipient.phone, submission_id, ...) to a static message in details.fields; a store, strategy or vehicle the form does not offer is one of them. ORDER_INTAKE_DAILY_LIMIT (429) when the form reached its daily order limit. Refusals are the uniform FORBIDDEN (403) or SESSION_EXPIRED (410); RATE_LIMITED (429) and ORDER_INTAKE_UNAVAILABLE (503) carry Retry-After.