Agentic commerce glossary: 40 terms explained

Agentic commerce is shopping and payment carried out by AI agents within limits that a person or business has set. This glossary defines more than 40 terms you will meet in protocol specifications, card network programs and merchant integrations, grouped by topic, with a link to the full guide where this site has one. Protocol vocabulary changes between versions, so check the version a partner actually implements before relying on a definition.

Use the table to find the right group of terms for the question you are trying to answer.

What are the core agentic commerce terms?

Agentic commerce

Shopping and payment carried out by an AI agent for a person or business, within limits they set. The agent can complete the purchase, not only recommend it. See what agentic commerce is.

AI agent

Software that uses a model to plan and take actions toward a goal, such as calling tools and APIs. In commerce, it searches products, builds carts and may pay.

Principal

The person or business an agent acts for. The principal's instructions and limits define what the agent is allowed to do.

Agentic payments

The payment side of agentic commerce: an agent initiating or completing a payment with credentials and limits delegated by its principal. See agentic payments operations.

Conversational commerce

Buying through a chat interface where the person makes each decision. The difference from agentic commerce is who completes the purchase; see agentic vs conversational vs headless commerce.

Headless commerce

An architecture that separates the storefront from the commerce engine behind APIs. Those APIs are what agents call.

Human present and human not present

Whether the buyer is in the session when the agent pays. It changes how the buyer can be authenticated and what evidence the merchant needs later.

Agent platform

The product in which an agent runs, such as an AI assistant, and the company that operates it. Which agent does what maps the roles.

Which protocol terms should you know?

ACP (Agentic Commerce Protocol)

An open standard for agent checkout and delegated payment. Stripe's documentation describes it as created by Stripe, OpenAI and Meta. Stripe: Agentic Commerce Protocol See what the Agentic Commerce Protocol is.

UCP (Universal Commerce Protocol)

An open standard that lets different participants in commerce transactions interoperate, including capability discovery and checkout. Stripe lists itself as a member of its Tech Council. Stripe: UCP See testing a UCP checkout.

AP2 (Agent Payments Protocol)

A protocol for signed mandates that prove what a user authorized an agent to pay for. It leaves catalog and checkout APIs to other protocols. AP2 specification See what AP2 is.

MCP (Model Context Protocol)

An open protocol for connecting AI applications to tools, resources and prompts. It is general agent plumbing, not a payment protocol; see MCP, A2A, ACP, AP2 and UCP compared.

A2A (Agent2Agent)

A protocol for agents to discover each other, authenticate and exchange messages and long-running tasks. A completed A2A task is not proof that an order exists.

HTTP 402 Payment Required

An HTTP status code long reserved for payments. Machine payment protocols use it so a server can state a price before returning a resource. x402: HTTP 402 See how agent stablecoin payments work.

x402

An open payment protocol built on HTTP 402, mainly used for stablecoin payments per request. See what x402 is.

MPP (Machine Payments Protocol)

A machine payment protocol that Stripe says it co-authored with Tempo. It uses the 402 pattern and accepts stablecoins and cards. Stripe: MPP

Capability negotiation

A step in which the agent and the seller each declare supported features and proceed with the overlap. ACP added it in its 2026-01-16 release. ACP: changelog

Payment handler

A declared way of paying that a seller accepts, such as a tokenized card processed by a particular provider. ACP's 2026-01-30 release moved payment declarations to handlers, a breaking change.

Checkout session

The object an agent creates with a seller to hold items, totals, delivery options and payment state until the order is completed or canceled.

Which authority and mandate terms matter?

Mandate

A verifiable record of what a principal authorized an agent to do: which items, merchants, amounts and time window. See an agent can find the product, but may it buy it?.

Intent mandate

A term from earlier AP2 explanations for the signed record of a user's instruction and limits before the agent shops. The current AP2 specification uses different terms; see what AP2 is.

Cart mandate

A term from earlier AP2 explanations for the signed approval of a specific cart and price. Check which version a partner implements before mapping fields.

Checkout mandate

In the AP2 v0.2 specification, a mandate that constrains the commercial checkout, such as the merchant, items and amounts.

Payment mandate

In the AP2 v0.2 specification, a mandate that constrains the financial action and is bound to a particular checkout.

Delegated payment

Letting an agent pay with credentials the buyer delegated, without exposing raw card details to the agent or merchant. In ACP, the Delegate Payment specification turns a credential into a limited token.

Allowance

ACP's limits on a delegated payment token: maximum amount, currency, expiry, and the checkout session and merchant it may pay. ACP: delegate payment

Spend control

A rule enforced when a card or token is authorized, limiting merchant categories, amounts or time windows. See agentic commerce in B2B procurement.

KYA (Know Your Agent)

Checks that establish which agent is acting, who controls it and what it may do, by analogy with KYC for people. See KYA as an identity control plane.

Which payment credential terms should you know?

Shared payment token (SPT)

Stripe's token that gives a seller scoped access to a buyer's payment method for an agent-initiated purchase. OpenAI names it as the first implementation of its Delegated Payment Spec. Stripe: shared payment tokens

Network token

A token issued by a card network's token service that replaces the card number for a specific merchant, device or use, and is updated when the card changes. See network tokenization.

Agentic token

A network token provisioned for use by an AI agent, so the issuer can recognize the agent and apply its limits. Stripe lists agentic network tokens from Visa and Mastercard among the ways agents can pay with Issuing cards. Stripe: Issuing for agents See what Visa and Mastercard are building.

Virtual card

A card number issued without a physical card, usually with controls on amount, merchant or validity. See virtual card accounts.

Single-use virtual card

A virtual card valid for one transaction, often used when an agent pays through an ordinary browser checkout. See why agentic cards need a mandate ledger.

Vault token

A reference to card details held in a compliant vault. ACP's delegate payment endpoint returns one that works only within its allowance.

Credential on file

A payment credential a merchant stores, with the customer's agreement, for later payments. See saved payment method consent.

Stablecoin

A crypto-asset designed to hold a stable value against a reference asset such as the US dollar. See stablecoin payments in 2026.

Visa Intelligent Commerce

Visa's portfolio of services for AI-driven commerce, which Visa first introduced in April 2025. Visa: Find and buy with AI See what Visa Intelligent Commerce is.

Mastercard Agent Pay

Mastercard's agentic payments program, unveiled in April 2025. Mastercard: Agent Pay See what Mastercard Agent Pay is.

Which authentication and risk terms matter?

SCA (strong customer authentication)

The EU and UK requirement to authenticate certain payments with two independent factors from knowledge, possession and inherence, subject to exemptions. See PSD2 SCA exemptions.

3-D Secure (3DS)

The card protocol issuers use to authenticate online payments, either without buyer interaction or with a challenge. See EMV 3DS2 step-up logic.

Step-up

An extra authentication step requested when risk or rules require it. For agents, it means handing control back to the person.

Passkey

A FIDO credential that replaces a password with a key pair, used on the device after a biometric check or PIN. Passkeys are one way a buyer can confirm an agent's purchase. See testing the lost-phone journey.

MIT (merchant-initiated transaction)

A card payment the merchant initiates under an earlier agreement with the cardholder, without the cardholder in the session. See recurring card payments.

CIT (customer-initiated transaction)

A payment the cardholder initiates in the session. Agent purchases raise the question of which category applies and who must authenticate.

Chargeback

A card dispute in which the issuer reverses a transaction under network rules. See chargebacks are a product problem and, for agent purchases, agentic commerce chargebacks and liability.

Idempotency key

A unique key that lets a request be retried without creating a second order or payment. See payment idempotency.

Which merchant and operations terms matter?

Product feed

A structured file or API listing products, prices, availability and fulfillment details for agents to search. See preparing a store for AI shopping agents.

Merchant of record

The legal seller responsible for the sale, taxes, refunds and disputes. In ACP, the seller remains the merchant of record. See merchant of record vs payment processor.

PSP (payment service provider)

A company that processes payments for merchants and, in agent flows, often issues or accepts the delegated tokens.

Order webhook

An event the seller sends to the agent platform when an order is created, shipped, canceled or refunded. See payment webhooks that arrive twice or out of order.

Instant Checkout

OpenAI's in-ChatGPT checkout built on ACP. OpenAI later said merchants can use their own checkout experiences while it focuses on product discovery. OpenAI: Powering product discovery

Punchout

A procurement pattern in which a buyer's procurement system opens a supplier's catalog and receives the cart back for approval. See agentic commerce in B2B procurement.

Agent-ready checkout

A checkout that agents can call through an API, with clear totals, policies and payment options they can understand and accept. For Gulf specifics, see agentic commerce in the UAE and Saudi Arabia.

FAQ

What does agentic mean in agentic commerce?

It means the AI can act, not just advise. An agentic system completes steps such as checkout and payment within limits its principal has set.

What is the difference between ACP, UCP and AP2?

ACP and UCP define how agents interact with merchants, including checkout. AP2 focuses on signed mandates that prove what a user authorized an agent to pay for.

What is a mandate in agentic commerce?

A verifiable record of what a person or business authorized an agent to buy, from whom, up to what amount and for how long.

What is a shared payment token?

Stripe's scoped token that lets a seller charge a buyer's payment method for one agent-initiated purchase without receiving the card details.

Is x402 the same as MPP?

No. Both use HTTP 402 for machine payments, but they are separate protocols: x402 began at Coinbase, and Stripe says it co-authored MPP with Tempo.