Lints a caller-supplied Universal Commerce Protocol (UCP, from Google and Shopify, announced NRF 2026-01-11, Apache-2.0 spec on GitHub) checkout resource against the schema pinned at tag v2026-04-08 of the published UCP repository. Checks the resource-level required fields, the status enum, ISO 4217 currency form, integer minor-unit amounts, and the exactly-one-subtotal / exactly-one-total rule on the totals breakdown. A payload declaring a version outside the pinned allowlist is never upgraded to conformant; it is reported as version-unknown regardless of how clean the structure otherwise is.
The demo payload below is synthetic and already loaded, so you can press Run without entering anything of your own.
It does not contact a UCP or ACP endpoint, does not create or complete a checkout session, and does not validate payment-instrument or merchant identity beyond the fields present in the pasted resource. A CONFORMANT verdict is a structural-shape result against the pinned schema, not a claim of UCP platform certification.
ART-12 checks ACP checkout-session conformance and ART-01 validates the AP2 payment mandate chain. Together with this node they form the Agentic Commerce Convergence chain, binding UCP discovery/cart, ACP checkout, and AP2 payment authorization into one composite receipt.