Agent Will Pay

Agentic Commerce 101: what happens when your AI agent pays

As of 26 October 2026. Every dated claim below links to its source.

What it is

Agentic commerce means an AI agent does not just find things for you — it completes purchases on your behalf, within permissions you set in advance. The agent might pay a supplier invoice, buy digital services for a business, or (soon, in controlled pilots) check out a shopping cart. The human sets the boundaries; the agent operates inside them.

How a payment works, step by step

  1. You set permissions. A spending limit, allowed merchant categories, and whether each purchase needs your approval. These are the controls every serious product offers.
  2. The agent shops or acts. It finds providers, compares, and proposes — or, in pre-authorised cases, acts without you on the call (Google’s AP2 calls this a “Human Not Present” payment).
  3. Authorisation evidence is created. In AP2 this is a set of cryptographically signed mandates: an Intent Mandate (what the agent may do), a Cart Mandate (the exact items and price), and a Payment Mandate (the signal to the network that an agent is involved). The signature proves authorisation; it does not by itself prove the purchase was wise.
  4. Payment uses tokenized credentials. A stand-in for your card number, with the limits attached. Your raw card number is never handed to the agent or the merchant.
  5. The network and issuer authorise in real time, with fraud monitoring, and you get a record you can dispute.

The protocol landscape (and why there are so many)

ProtocolWhat it doesWho / status
AP2 (Agent Payments Protocol)Authorises: proves the buyer authorised the agent’s transaction, via signed mandates. It does not settle money.Google, announced Sep 2025; v0.2 Apr 2026, donated to the FIDO Alliance; 60+ organisations involved.
x402Carries the payment exchange over HTTP: a server quotes a price, the client signs and pays, a facilitator settles.Coinbase, May 2025; v2 Dec 2025; Linux Foundation stewardship Jul 2026.
MPP (Machine Payments Protocol)Stripe’s protocol for machine payments.Stripe; listed among the protocols Visa’s Connect accepts.
ACP (Agentic Commerce Protocol)OpenAI’s protocol for agent commerce.OpenAI; listed among the protocols Visa’s Connect accepts.
UCP (Universal Commerce Protocol)Google’s commerce protocol, including checkout.Google; merchant rollout announced at Google I/O 2026.

These are complementary, not competing: AP2 proves authorisation, x402 moves the money, and the card networks’ products (Visa Intelligent Commerce, Mastercard Agent Pay) tie them to cards, banks and stablecoins with controls. Visa’s Connect product is explicitly designed to accept across several protocols through one integration.

What is real, and what is not yet true

Real, as of October 2026: live B2B invoice pilots (Visa, BILL, Billtrust, 20 Oct 2026); machine-to-machine early access with worked demos (Mastercard, 20 Oct 2026); a neutral, FIDO-governed authorisation standard (AP2 v0.2, Apr 2026); and a shared control model everywhere — limits, categories, approvals, tokenized credentials.

Not yet true: universal consumer checkout — “let any agent buy anything anywhere” does not exist. Most of what is live is B2B invoices, machine-to-machine services, and controlled pilots. Consumer agent checkout at scale is still rolling out, provider by provider. Any product that claims otherwise is ahead of the evidence.

The four questions, again

Before you enable agent payments anywhere: what exactly did I authorise? What happens if it buys the wrong thing? Can I revoke it in one action? Are the credentials tokenized? If a product cannot answer all four clearly, do not enable it. See the homepage for the full version.

Sources