Agentic Commerce Protocol
The Agentic Commerce Protocol, usually shortened to ACP, is one of the named efforts to standardise agent initiated purchases, so that an agent can present an order to a merchant through an agreed interface rather than by filling in a checkout form built for a person.
Merchants tend to encounter it through their platform rather than by implementing it. That is the sane order: the platform adopts, the merchant keeps its catalogue accurate, and the protocol fills its fields from data that was already correct.
As with every effort in this space, the detail is moving. What is stable is the shape of the problem, which is that a purchase should not depend on an agent guessing which button is the real one.
Why it matters to a store
Adopting a protocol is not a prerequisite for being agent ready, and waiting for one is not a reason to leave a broken checkout in place. Agents will keep falling back to driving your ordinary storefront, and that fallback is where stores lose purchases today.