Buried in the agentic-commerce news cycle this week is a protocol that's been running since last September with an angle worth separating from the headlines: Google's Agent Payments Protocol, or AP2, doesn't just authorize an AI agent to buy something — it manufactures a paper trail for the purchase before it happens. AP2 is an open protocol for authorising and processing payments initiated by AI agents, announced by Google in September 2025, and designed to work with payment methods including cards, bank transfers and stablecoins. The mechanism is what matters here: AP2 uses cryptographically signed records, referred to as mandates, to record and verify a user's instructions and approval for an agent-assisted transaction. Rather than a single approval click, the protocol breaks consent into stages — intent mandates, cart mandates and payment mandates as mechanisms for linking a user's authorised intent to a specified purchase and payment action. That's a different design choice than the identity-and-authentication framing dominating most agent-commerce coverage right now, including Sierra and Meta's newly drafted Personal Agent Protocol, which focuses on letting a business tell an AI agent apart from a human customer. AP2 assumes you already know it's an agent — the open question it's trying to answer is whether the agent actually had permission to spend money, and whether that permission survives a dispute later. A signed mandate chain is evidence a merchant, a card network, or a regulator can audit after the fact, independent of whatever the agent claims it was told to do. This is the quieter but arguably harder problem in agentic commerce. Identity standards tell a counterparty who's knocking. Mandate chains tell everyone, after the money has moved, whether the knock was authorized — which is exactly the kind of question that surfaces in chargebacks, fraud investigations, and the inevitable first lawsuit over an agent that bought the wrong thing, or too much of the right thing. AP2's bet is that payment rails need their own signed-receipt layer, separate from whatever identity or discovery protocol the agent used to show up in the first place. Whether AP2's mandate structure becomes the de facto standard or gets folded into something like PAP's business-facing handshake is still unsettled — but the distinction between proving who you are and proving what you were told to do is going to keep resurfacing as more of these protocols stack on top of each other. One practical tell: none of the mandate fields are optional metadata. They're the thing a court or a card network would actually look at.