UCP spec and schema links resolve

What we check

Each capability, service and payment handler in a UCP profile can name a spec URL and a schema URL. We collect those links and ask the UCP spec hosts we trust whether each one answers: ucp.dev, shopify.dev and pay.google.com. A link on any other host is listed but not checked.

Why it matters

An agent or a developer follows these links to learn how your capabilities and handlers behave. A link that returns 404 sends them nowhere.

How we check

We never send these requests to your store. Each link gets one small request (the first kilobyte only), and answers are kept for a day, so a scan seldom asks again. A 200 or 206 counts as resolved and a 404 or 410 counts as broken. Anything else (an error, a timeout, a host off our list, or our own per-scan limit) is listed as not checked and never counts against you. The score is resolved links out of resolved plus broken. 80 or more is a PASS and 40 or more is a WARN. SKIPPED: there is no profile, we could not read it, it is not JSON, or no link could be checked.

How to fix it

1. Point each spec and schema URL at the page the UCP project publishes for the release you declare, under https://ucp.dev/<version>/.
2. Replace or remove every link we list as broken, then publish the profile again.

What good looks like

"dev.ucp.shopping.checkout": [{
  "version": "2026-08-25",
  "spec": "https://ucp.dev/2026-08-25/specification/overview/",
  "schema": "https://ucp.dev/2026-08-25/schemas/capability.json"
}]

Sources

• UCP 2026-08-25 specification: overview
• UCP Checker: how we check

Read more

• UCP explained

  The Universal Commerce Protocol: the profile a store publishes at /.well-known/ucp, the capabilities it declares there, and the checkout flow from a new basket to a placed order.