UCP commerce journey
Standardizes discovery, product and offer data, checkout, and order lifecycle interactions between agents and businesses.
Official sources · UCP verified Jul 24, 2026
UCP and AP2 solve different layers of agent commerce
Universal Commerce Protocol (UCP) covers the commerce journey from discovery through checkout and order lifecycle. Agent Payments Protocol (AP2) complements it with verifiable intent, cart, and payment-authorization artifacts.
UCP revision 20bb02d1e089 · AP2 revision e1ea56db72a6 · AP2 source checked Apr 29, 2026
How the layers fit together
Intent Mandate
Records the user's instructions and constraints so an agent's authority can be evaluated later.
Cart Mandate
Captures the concrete purchase terms presented for authorization, including what will be bought.
Verifiable authorization
Uses signed, inspectable artifacts so participants can reason about consent and maintain an audit trail.
A practical architecture
Use UCP for merchant-facing commerce capabilities, AP2 when a payment flow needs verifiable authorization, and A2A or MCP where agents need to discover or invoke external services. These protocols complement existing identity, fraud, payment, privacy, and consumer-protection controls; they do not replace them.
Implementation review
Questions to answer before money moves
Protocol support does not replace your legal, fraud, security, or payment-compliance responsibilities.
Authority
What may the agent buy, for how much, during which time window, and on whose behalf?
Consent
Which user action authorizes the exact terms, and how is that authorization recorded?
Identity
How are the participating agent, merchant, user, and credential issuer verified?
Failure handling
What happens on price changes, inventory changes, timeouts, duplicate requests, and declined payments?
Auditability
Can a reviewer reconstruct the intent, offer, approval, payment result, refund, and dispute?
Use maintained protocol sources
UCP and AP2 are evolving standards. Review their maintained documentation, schemas, SDKs, and reference scenarios, then pin the versions your production integration has tested.