AP2

The specification names roles rather than products. A shopping agent performs product discovery, builds the checkout and executes the purchase. A credential provider supplies the payment credential. A merchant provides and completes the checkout, with a payment processor acting for it. And a separate surface role captures a person's informed consent before any signed mandate exists.

Two mandate types split what was agreed from what was authorised. A checkout mandate captures the purchase; a payment mandate authorises payment against a particular instrument. The specification describes mandates as tamper-evident, cryptographically signed objects. It specifies selective-disclosure tokens for securing them, which is what lets one party check an instruction without being shown everything around it.

Against the HTTP payment rails it sits above rather than beside. AP2 states that it operates as a security feature within a commerce protocol, designed to be compatible with the Universal Commerce Protocol. Its published scenarios include an agent transacting with no person present, using x402 for the payment itself. The question it answers — what was authorised, and by whom — is not the question a payment challenge answers.