UCP validator
Check that your Universal Commerce Protocol profile is discoverable at/.well-known/ucpand that your OAuth Authorization Server metadata is in place for Identity Linking.
What is UCP?
UCP — the Universal Commerce Protocol — is an open standard for agent-driven commerce. It defines checkout sessions, identity linking, and order-management webhooks on top of REST and JSON-RPC, and integrates with AP2, A2A, and MCP. The discovery profile at /.well-known/ucp is how agents find your services, capabilities, and signing keys.
Why adopt it
If your storefront is going to be reachable by purchasing agents — concierge agents, travel planners, B2B procurement bots — UCP is the discovery layer that lets them find your checkout, link a customer identity, and listen for order status changes without bespoke integration. Without a UCP profile, an agent can’t tell what you sell or how to pay you.
What we check
- C8 — UCP profile.
/.well-known/ucpreturns 200 with valid JSON. The required top-levelucpobject containsversion,services,capabilities, andsigning_keys. - C9 — OAuth Authorization Server metadata. Only runs when C8 is present.
/.well-known/oauth-authorization-serverreturns 200 with parseable JSON containing the RFC 8414 required fieldsissuerandresponse_types_supported. Recommended fields (authorization_endpoint,token_endpoint, scopes, grant types) are reported but don’t fail the check.
Minimal valid example
{
"ucp": {
"version": "2026-04-08",
"services": {
"checkout": { "endpoint": "https://api.example.com/checkout" }
},
"capabilities": {
"checkout_sessions": { "supported": true }
},
"signing_keys": [
{
"kty": "OKP",
"crv": "Ed25519",
"kid": "ucp-2026",
"x": "..."
}
]
}
}Top-level ucp object with all four required fields. payment_handlers is optional and omitted here.