Universal Commerce Protocol (UCP) — how to make your site agent-ready

What it is

Universal Commerce Protocol is an emerging standard that lets agents browse products, build carts, and check out on any participating storefront without screen-scraping. Conventional discovery: a /.well-known/ucp.json descriptor pointing to catalog and checkout endpoints, optionally referencing OpenAPI.

Remediation Prompt

I want to improve my site's agent readiness. Please implement the following fix for Universal Commerce Protocol (UCP) across our codebase.

Instructions:
Please fix the Universal Commerce Protocol (UCP) issue on my site so it is agent-ready.

How we test it

Step	Method	URL
A	GET	`/.well-known/ucp.json`
B	GET	homepage HTML `<link rel="ucp-catalog" href="…">` hint

Pass Warn Fail Matrix

Condition	Status	Score
A exists, parses, has `catalog` + `checkout` endpoints that resolve	pass	1.0
A exists but listed endpoints 404	warn	0.4
Only `<link rel>` hint	warn	0.3
404	fail	0.0

Remediation Prompt

If you run a storefront, add Universal Commerce Protocol support.

1. Publish /.well-known/ucp.json:
    {
      "version": "1.0",
      "catalog": "https://example.com/api/ucp/catalog",
      "checkout": "https://example.com/api/ucp/checkout",
      "openapi": "https://example.com/api/ucp/openapi.json",
      "supportedPaymentMethods": ["x402-usdc", "stripe-pi"]
    }

2. Implement the endpoints. The catalog supports filter/search queries and returns structured product records. The checkout accepts a cart object and a payment intent, returns a session or receipt.

3. Advertise on the homepage:
    <link rel="ucp-catalog" href="https://example.com/api/ucp/catalog">

Prefer UCP over ACP if you need more flexibility; most sites should do both.

References

ucp.dev

Test Fixtures

pass.json
warn-dead-endpoints.json
fail-404.json