Declare ucp.capabilities
No capabilities are declared, so agents cannot tell what your store supports.
Why it matters
Agents read the capabilities map to know whether to attempt cart, checkout, payment tokenization, identity linking, etc. An empty list collapses the agent to "browse only" mode.
Show fix
Name spec capabilities under dev.ucp.shopping.* (for example dev.ucp.shopping.checkout). Each entry needs a version, a spec URL and a schema URL.
"ucp": {
"capabilities": {
"dev.ucp.shopping.checkout": [
{
"version": "2026-08-25",
"spec": "https://ucp.dev/2026-08-25/specification/checkout/",
"schema": "https://yourstore.com/.well-known/ucp/schemas/checkout.json"
}
]
}
}
