AP2 (Agent Payments Protocol): mandates for agent payments
Google's Agent Payments Protocol chains intent, cart and payment mandates as signed credentials and has been with the FIDO Alliance since April 2026. Version 0.2 allows payments without a human present, based on pre-authorised instructions.
The trio
The intent mandate describes what may be bought; the cart mandate binds the concrete basket with a merchant signature; the payment mandate authorises the payment.
At Mandact
POST /v1/interop/ap2 accepts the trio and decides with the same engine: merchants become the counterparty list (MD-304), SKUs allowed line items (MD-312), expiry the validity window (MD-203), the confirmation requirement an escalation (MD-401).
Named honestly
The trio carries no user-side amount limit, requires_refundability has no counterpart, and AP2 0.1 leaves the canonicalisation of cart_hash open — the acceptance pins it down and checks against Google's own signing helper.
Status
Acceptance implemented (lib/interop/ap2.ts); acceptance anchor green.