Universal Commerce Protocol: Checkout capability missing
UCP_CHECKOUT_MISSING · v1.0
What it detects
A valid UCP profile exists but declares no dev.ucp.commerce.checkout capability.
Why it matters
Discovery without a checkout capability tells an agent the merchant is UCP-aware but still leaves it with no standardized way to actually complete a purchase.
How to fix
- Check the (valid) UCP profile at `/.well-known/ucp` for a `dev.ucp.commerce.checkout` entry under `capabilities`. - Add a `checkout` capability entry pointing to your checkout-session-creation, cart-management, and tax-calculation endpoints, per ucp.dev/specification/checkout. - Wire these endpoints to real backend checkout logic — the capability declaration must correspond to a working implementation, not a placeholder. - Verify: `curl` the UCP profile, confirm the checkout capability is present and valid, and exercise the declared checkout endpoint end-to-end (create session → complete order).
References
Last reviewed: 2026-09-01 · rule v1.0