Glossary of agent payment terms

All terms

/.well-known/ucp

The path where a business publishes its UCP profile listing services, capabilities and payment handlers.

Agent Pay for Machines (AP4M)

Mastercard's service for machine-to-machine purchases of digital services, built on x402 and settling across cards, accounts and stablecoins.

Agent Payments Protocol (AP2)

A protocol of signed mandates that record what a user authorised an agent to buy and pay, now standardised in FIDO Alliance working groups.

Agent profile

A JSON document an agent hosts at a well-known URL and references on each UCP request, used by Shopify to verify agents and set access.

Agent Purchase Protection

American Express's announced protection for eligible Card Members against charges caused by agent error when the agent sent authenticated intent.

Agent Terms (Amazon)

Amazon's Conditions of Use section requiring agents to identify themselves and forbidding human mimicry and CAPTCHA solving.

Agentic commerce

Buying and selling where a software agent acting for a person or business searches, selects and pays, with the person approving by instruction or per purchase.

Agentic Commerce Protocol (ACP)

An Apache 2.0 protocol, maintained by OpenAI, Stripe and Meta, for checkout sessions, delegated payment tokens and product feeds between agents and merchants.

Agentic Payment Enabler

Visa term for an entity connected to Visa that lets Agentic Payment Providers participate and initiate Agentic Transactions without engaging cardholders itself.

Agentic Payment Provider

Visa term for an application that searches, discovers and buys for a cardholder on a payment instruction, stores and passes a token, and is not involved in authorisation or settlement.

Agentic Repeated Transaction

Visa term for a series of future agent purchases the cardholder consented to, continuing until changed, cancelled or expired.

Agentic Storefronts

Shopify's Admin setting that syndicates a store to ChatGPT, Copilot, Google AI Mode and Gemini with the merchant as merchant of record.

Agentic token

A network token issued for a specific registered agent, carrying controls and making each agent transaction traceable.

Agentic Transaction

Visa term for an e-commerce transaction by an Agentic Payment Provider on cardholder-defined instructions, completed without direct cardholder-merchant interaction.

Amex ACE

American Express Agentic Commerce Experiences: a developer kit for agent registration, account enablement, intent, payment credentials and cart context.

Buy for Me

Amazon's agent feature that buys from other brands' websites for an Amazon customer, passing encrypted details to the brand checkout.

Cardholder-defined payment instruction

The criteria a cardholder gives an agent for searching and buying, which the agent must follow and which carries a stated expiry date under Visa rules.

Delegated payment

An ACP pattern in which the agent platform passes payment data to the merchant's PSP and receives a merchant-scoped token instead of raw card data.

Dispute Condition 10.4

Visa's fraud dispute condition for card-absent transactions, where agent purchases land; merchants can defeat it with matching data from prior undisputed orders.

Dynamic Token Verification Code

Mastercard's agentic token formatted for standard card fields, so a verified agent can pay through an existing checkout form.

Facilitator

In x402, a service that verifies a payment payload and settles it onchain for the server.

HTTP 402 Payment Required

An HTTP status code reserved for payment; x402 and MPP use it to tell a client that a resource has a price.

HTTP Message Signatures

RFC 9421: a way to sign selected HTTP components, carried in Signature-Input and Signature headers.

Human not present

An agent payment completed without the user present at the moment of purchase, on instructions the user approved earlier.

Instant Checkout

OpenAI's in-chat purchase feature in ChatGPT, launched 29 Sep 2025 on ACP and replaced on 24 Mar 2026 by merchant-site checkout.

Intelligent Commerce Connect

Visa's single acceptance integration for agent-initiated payments over TAP, MPP, ACP and UCP, in pilot since April 2026.

Know Your Agent (KYA)

Verification of an AI agent's identity and operator before it may transact, by analogy with Know Your Customer.

Link Agent Wallet

Stripe Link's agent interface: the agent creates a spend request, the user approves, and Link returns a one-time credential.

Machine Payments Protocol (MPP)

An HTTP 402 protocol co-authored by Tempo and Stripe with one-time, session and subscription intents across stablecoins, cards and Lightning.

Mandate

In AP2, a signed verifiable credential that records a user's authorisation; v0.2 uses a Checkout Mandate and a Payment Mandate, each open or closed.

Mastercard Agent Pay

Mastercard's agentic payments program built on registered agents and agentic tokens, with an acceptance framework for merchants.

Merchant of record

The party that sells to the buyer, appears on the statement, and carries refunds, tax and chargebacks; in current agent protocols this stays the merchant.

Payment handler

In UCP, a named entry in the payment_handlers registry that tells the platform how to collect and pass payment for that business.

Probability score (agent)

Mastercard's score of the likelihood that a transaction was initiated by an AI agent, given to issuers for authorisation decisions.

SD-JWT

Selective Disclosure JSON Web Token: a signed token where the holder reveals only chosen claims to each verifier.

Shared Payment Token (SPT)

A Stripe token that grants a seller a scoped right to charge a buyer's payment method, with a currency, maximum amount and expiry.

Trusted Agent Protocol (TAP)

Visa's scheme for agents to sign requests with HTTP Message Signatures so merchants can verify the agent and receive consented identifiers.

Universal Commerce Protocol (UCP)

An Apache 2.0 protocol for discovery, carts, checkout, identity linking and orders between platforms and businesses, governed by a Tech Council led by Google and Shopify.

Verifiable Intent

An open SD-JWT credential format, draft v0.1, chaining credential provider, user and agent and binding purchase constraints.

Visa Intelligent Commerce

Visa's program for agent payments with tokenised credentials, payment instructions and rules for agentic providers.

Web Bot Auth

An IETF draft for bots and agents to sign HTTP requests with HTTP Message Signatures and a published key, used as the identity layer by TAP and Agent Pay.

x402

An HTTP 402 payment protocol in which a server states its price, the client pays (usually in stablecoins) and retries; governed by the x402 Foundation.