What is ACP, the Agentic Commerce Protocol?

What ACP actually specifies

ACP is the most commerce-specific of the four protocols in this space. Where MCP describes how an agent finds and calls tools generally, ACP describes the commerce objects: how a product feed should be formatted, what a checkout session looks like, and how payment processing is delegated from the agent's environment to the merchant's processor.

The April 2026 revision covers checkout, payment delegation, cart, feed and authentication. It also includes an integration hook so an ACP-aware agent can advertise its checkout capability through MCP tool discovery — which is the clearest signal in the whole space that these protocols were designed to compose rather than displace one another.

The 2026 pivot, and why it matters more than the spec

OpenAI shut down Instant Checkout and repositioned ACP toward product discovery and merchant-controlled experiences instead of completing purchases inside the chat interface. The protocol continues; what changed is where the industry expects the transaction to happen.

Adoption followed that shape. Target, Sephora, Nordstrom, Lowe's, Best Buy, Home Depot and Wayfair integrated ACP on the discovery side rather than for in-chat purchase completion.

For a merchant deciding where to spend engineering time, this is the most useful fact available. The largest retailers in the category, with the most resources and the earliest access, concentrated on being findable rather than on being transactable inside the assistant. Discovery is the layer that has converged; checkout is still moving.

What ACP asks of a merchant

The obligations divide cleanly into the part that is durable and the part that is still in motion.

• A conformant product feed — accurate price, availability and identifiers, kept current. This is the durable part, required by UCP as well, and useful to assistants that implement neither.
• A checkout session endpoint the agent can drive without a browser, returning a binding total including shipping and tax.
• Payment delegation, where the agent's environment hands processing to your processor rather than holding credentials itself.
• Authentication, so the merchant can establish which agent is calling and on whose behalf.

Should you implement ACP now?

The honest answer for most merchants is: implement the feed, wait on the rest.

The feed requirement is shared across every protocol in the space and pays back regardless of which wins — it is the same structured product data that improves classical SEO and that assistants already use without any protocol at all. Building it is not a bet.

The checkout and payment-delegation layers are a bet, and the party best positioned to know shut down their own in-chat checkout this year. If you are a very large retailer with the resources to track a moving specification, there is a first-mover case. If you are not, the cost of implementing a checkout integration twice exceeds the cost of being six months late to one.

On PlatformDTC the feed layer is a platform default — storefronts server-render structured product data as the output of the publish pipeline — and the programmatic cart and quote path exists through the Agent Gateway, so the work that a checkout protocol would sit on top of is already there.