Report one product's current offer from the queried source (price in integer minor units, availability, provenance) — or, given a merchant host plus the merchant's own itemId, prepare/re-check NORMALIZED CHECKOUT EVIDENCE over the merchant's declared UCP/ACP checkout data: items, currency, subtotal, discount, tax, fees, shipping, total, fulfillment, policy links, expiry and an evidence hash, with bounded truth states 'verified' / 'changed' / 'unsupported' / 'unavailable' / 'unverified'. Pass priorEvidence (component hashes from an earlier answer) to detect price/stock/shipping/terms changes between preparation and re-check. 'verified' means fetched, parsed and internally consistent — never 'safe', never 'approved', never a guarantee the merchant honors the quote. A price is never guessed. Answers come from the queried source at the stated retrieval time — a UCP or ACP merchant, a partner catalog source, or a clearly-labelled synthetic fixture in dev/test; provenance.sourceAuthority names which, and every answer carries the markets that source declares. Preflight evidence only — this server never places, modifies or cancels an order and never touches a payment; the merchant stays merchant of record.