Protocol
MEDIUMEach capability has version + spec + schema
Every `capabilities[]` entry declares `version`, `spec`, and `schema`. Capabilities missing version/spec/schema can't be matched against agent support tables — agents skip them silently.
What this check looks for
Capabilities advertise optional contracts that agents can opt into. Each entry MUST carry: `version` (the capability's spec generation), `spec` (human-readable specification URL), and `schema` (machine-readable schema URL). Capabilities missing any of these can't be matched against agent support tables.
Which AI surfaces it affects
- Google AI Mode (UCP)60
- Microsoft Copilot40
- ChatGPT (ACP)20
- Perplexity20
- Meta AI20
Weighted against the live specs — ACP 2026-04-17, UCP 2026-04-08.
How to fix it
Populate version, spec, and schema on every capabilities[] entry
Shopify
A few minutes- Update the UCP JSON your handler emits: every capability needs version+spec+schema.
BigCommerce
A few minutes- Update the edge worker producing the UCP profile: each capability declares version+spec+schema.
WooCommerce
A few minutes- Edit the UCP JSON to set version+spec+schema on every capability entry.
Custom / headless
A few minutes- Populate version, spec, and schema on every capabilities[] entry.
- Drop entries you don't fully support today rather than leaving them half-declared.
<!-- /.well-known/ucp (excerpt) -->
{
"capabilities": [
{
"id": "ucp.search",
"version": "2026-04-08",
"spec": "https://ucp.dev/2026-04-08/specification/capabilities/search/",
"schema": "https://example.com/ucp/search/schema.json"
}
]
}The spec it's pinned to
UCP overview — capabilities
UCP capabilities are versioned add-on contracts atop the core services. Each capability MUST declare `version`, `spec`, and `schema` so agents can match against their supported set.
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.