Protocol
MEDIUMEach service's `spec` URL origin matches its namespace authority
Every `services[].spec` URL points at the canonical UCP authority or includes the service's namespace. A spec URL on an unrelated authority signals the service was copy-pasted from stale documentation — agents can't trust the conformance claim.
What this check looks for
UCP services declare their conformance via a `spec` URL pointing at the specification document. The URL should resolve to the canonical UCP authority (`ucp.dev`) or, for custom services, an authority that matches the namespace token. URLs pointing at unrelated domains indicate the merchant copied the entry from a stale source or is referencing an unofficial fork; agents fall back to default behaviour.
Which AI surfaces it affects
- Google AI Mode (UCP)80
- Microsoft Copilot60
- ChatGPT (ACP)20
- Perplexity20
- Meta AI20
Weighted against the live specs — ACP 2026-04-17, UCP 2026-04-08.
How to fix it
Point each service `spec` URL at the canonical UCP authority
Shopify
A few minutes- Update the UCP JSON your handler emits to reference the canonical ucp.dev spec URLs.
BigCommerce
A few minutes- Update the edge-served UCP profile to point each service's `spec` at the canonical authority.
WooCommerce
A few minutes- Edit the UCP JSON file and replace each service's `spec` URL with the matching ucp.dev URL.
Custom / headless
A few minutes- Update each `services[].spec` to the canonical URL on ucp.dev or your authority's namespace path.
<!-- /.well-known/ucp (excerpt) -->
{
"services": [
{
"namespace": "shopping",
"version": "2026-04-08",
"spec": "https://ucp.dev/2026-04-08/specification/shopping/",
"transport": "rest",
"endpoint": "https://example.com/ucp/shopping"
}
]
}The spec it's pinned to
UCP overview — service specs
Each UCP service references the spec it conforms to via a `spec` URL. URLs pointing at unrelated domains signal stale references or unofficial forks and break agent capability matching.
Does your store pass this check?
Run the full audit — 82 checks across five AI shopping surfaces. Most tools only check whether you get mentioned; we check whether an agent can buy from you.