Checker API

The Checker API is a hosted service at https://checker.ucphub.ai exposing two operations. It is stateless: nothing you send is stored.

The full interactive reference (schemas, try-it, examples) lives at checker.ucphub.ai/docs.

`POST /validate`

Validates a pasted UCP document — discovery profile, checkout session, cart, order, payment handler, and more — against the official UCP JSON Schemas. Pure and offline: nothing is fetched.

curl -X POST https://checker.ucphub.ai/validate \
  -H 'content-type: application/json' \
  -d '{
    "document": { "id": "cod", "version": "2026-04-08", "config": { "title": "Cash on delivery" } },
    "type": "payment_handler"
  }'

A 200 with valid: false means the request worked and the document did not conform — non-2xx is reserved for malformed requests. Pass "version": "draft" to validate against the upcoming spec release.

Pasting a full /.well-known/ucp response works too: the API detects the top-level ucp envelope, validates the inner object, and says so in a note.

`POST /check`

Probes a live storefront and returns a scored, graded agent-readiness report:

curl -X POST https://checker.ucphub.ai/check \
  -H 'content-type: application/json' \
  -d '{"url": "https://your-store.example"}'

Four checks feed the report:

Check	What it does
`ucp-profile`	Fetches `/.well-known/ucp` and validates it against the official schemas
`robots-txt`	Checks whether AI agents are allowed to crawl
`llms-txt`	Probes for an `llms.txt` file
`agents-md`	Probes for an `agents.md` file

Schema conformance is the backbone: a missing or invalid UCP profile caps the score at 40.

Limits

/validate request bodies are capped at 1 MiB.
/check is rate-limited per IP at the edge — space scans a few seconds apart.

POST /validate

POST /check

Limits

On this page

`POST /validate`

`POST /check`