What we check

We fetch /.well-known/ucp. It passes when the response is JSON with a version string and at least one of services, capabilities or payment.

What UCP is

UCP, the Universal Commerce Protocol, is an open standard for agent-led shopping that Google launched in January 2026 with large retailers and commerce platforms. The manifest tells a shopping agent what your store supports: product discovery, carts, checkout, order status, and how payment works. With it, an agent in an AI shopping surface can find a product in your catalog and complete the order.

If you do not sell products online, this check does not apply to you.

How to publish a manifest

Start with your platform. Several commerce platforms generate and host the UCP manifest for merchants, and some turn it on by default, so you may only need to enable a setting or connect a sales channel. Merchants on other platforms can usually join through Google Merchant Center.

If you run a custom store, you publish the manifest yourself and implement the endpoints it declares. The manifest carries a dated version and describes your services and capabilities in reverse-domain notation. Follow the UCP specification for the exact schema. A manifest that declares capabilities your store does not actually implement is worse than none, because agents will try to use them.

Common reasons it fails

• The path redirects to your storefront homepage.
• The manifest exists but has no version field.
• Bot protection on the store blocks requests that do not come from a known browser. Shopping agents hit the same wall.

Keep it in step with your store

Treat the manifest as part of your checkout. When you add a payment method or retire a capability, update the manifest in the same release.