# Commerce — Accepting Agent Payments and Checkout

> The agent-readiness dimension that accepts agent payments and checkout — x402, AP2, ACP and UCP — so an agent can transact with your site, not just browse.

## What the commerce dimension means

The commerce dimension lets an agent move value through your site: pay for access, complete a checkout, or settle a transaction on a user's behalf. It is the last dimension in the dependency order because an agent must already be able to discover, read, access and act on your site before a payment makes sense. Where access control can charge for crawling, the commerce dimension handles the full purchase and settlement flow an agent needs to buy something — the protocols that turn an agent from a reader into a customer.

## Signals and standards it covers

- **x402** — an HTTP-native payment scheme that settles agent payments using the long-reserved `402 Payment Required` status, so a paid resource can quote a price and accept payment in the request flow.
- **AP2 (Agent Payments Protocol)** — a framework for authorizing and mandating agent-initiated payments.
- **ACP and UCP** — agentic commerce and checkout protocols that standardize how an agent completes a purchase against a merchant.

The payment landscape is moving quickly; verify protocol details and any adoption or transaction figures against the primary specs at build rather than asserting them as fixed facts.

## How the Agent-Readiness Audit scores it

The Audit scores commerce on whether a declared agent-payment path exists and behaves correctly. A representative check passes when a paid resource responds with a valid `402` challenge under x402 (or declares a supported AP2/ACP/UCP flow) and exposes the price and accepted method in a machine-readable form. The pass criterion is the protocol handshake completing as specified — the agent can read the price, present payment, and receive the resource — not a subjective judgment about your store. Because most sites do not transact with agents at all, this dimension is scored as applicable-only.

Related: [the x402 spec](/protocols/payments/x402) · [Agentic Commerce & agent payments](/commerce) · [x402 defined](/glossary/x402) · [the Agent Protocol Atlas](/protocols) · [audit your site](/services)