Agentic Commerce Glossary

The fast-moving vocabulary of agentic commerce, defined in plain language. Where a term has its own reference page, the entry links to it. Suggest a term or a correction and it will be added.

A

A2A (Agent-to-Agent). An open protocol for agents to communicate and delegate tasks to one another. It is the coordination layer some payment work builds on, for example the x402 extension for A2A.

ACP (Agentic Commerce Protocol). Open standard for agent-to-merchant checkout, launched in September 2025. Its README describes OpenAI and Stripe as founding maintainers, while MAINTAINERS.md lists OpenAI, Stripe, and Meta as lead maintainers. Licensed Apache 2.0. See ACP explained.

Agent. Software that can take actions on a user’s behalf, including searching for and purchasing products. In commerce, the “shopper” may now be an agent rather than a person.

Agent Pay. Mastercard’s agentic payments program, announced April 2025. It uses Mastercard Agentic Tokens, built on the same tokenization behind contactless and Mastercard Payment Passkeys, and requires agents to be registered and verified before they can pay.

Agentic commerce. Commerce conducted by AI agents acting for a user: discovery, selection, authorization, and payment with limited human input. See What Is Agentic Commerce?.

AI-Ready Cards. Visa’s term, under its Intelligent Commerce program, for card credentials tokenized for agent use, so a chosen agent can be authorized to transact within limits the consumer sets.

AP2 (Agent Payments Protocol). Google-led standard for proving a user authorized a purchase, built around signed mandates (originally Intent, Cart, and Payment; now a Checkout Mandate and a Payment Mandate). Donated to the FIDO Alliance in April 2026. See AP2 explained.

C

Cart Mandate. In AP2’s original (v0.1) model, the signed record of the exact cart the agent assembled for the user to approve.

Checkout Mandate. In AP2’s revised (v0.2) model, one of two credential types, covering the authorization of a finalized checkout. It replaces the earlier Intent plus Cart split with open (pre-cart constraints) and closed (authorization) stages.

Commerce / checkout (layer). The stack layer where an agent browses, builds a cart, and completes a purchase with a merchant. ACP and UCP are the standards here. See the four layers.

D

Delegated payment. A pattern where the buyer authorizes a payment that an agent then presents to the merchant on their behalf, without the agent holding the raw payment credentials. ACP specifies a delegated payment flow; AP2 provides the authorization proof behind it.

Delegated authority. The general principle that an agent acts within authority a user granted, bounded by constraints such as budget, merchant, or time. Mandates and tokens are the mechanisms that make delegated authority verifiable.

Discovery (layer). The stack layer where an agent finds a merchant’s products and the tools it can call. MCP is the standard here. See the four layers.

F

Facilitator. In x402, the service that verifies and settles a stablecoin payment on-chain on behalf of the merchant, so the merchant does not have to operate blockchain infrastructure directly.

FIDO Alliance. The industry body for authentication standards (including passkeys). Google donated AP2 to FIDO in April 2026, where it advances through a Payments working group chaired by Mastercard and Visa and a new Agentic Authentication group.

H

Human-present / human-not-present. AP2 terms distinguishing a purchase a user is actively approving in the moment from one an agent completes later within pre-authorized limits. The distinction shapes how authorization is signaled to the merchant and network.

I

Instant Checkout. OpenAI’s in-chat buying experience in ChatGPT, launched September 2025 on ACP with Etsy live from day one. OpenAI scaled back native Instant Checkout in early 2026 toward apps and discovery that send shoppers to the merchant’s own checkout.

Intelligent Commerce. Visa’s program, announced April 2025, that opens its network to AI agents through AI-Ready Cards and, from April 2026, an “Intelligent Commerce Connect” on-ramp that works across multiple agent protocols.

Intent Mandate. In AP2’s original (v0.1) model, the signed record of what the user asked for, including constraints like budget.

M

Mandate. A cryptographically signed, tamper-evident statement of authorization, expressed as a verifiable credential, that an agent can present as proof of consent. Mandates are the core trust primitive in AP2.

MCP (Model Context Protocol). Anthropic’s standard for how agents discover and call tools and data, donated to a foundation under the Linux Foundation in December 2025. In commerce it acts as the discovery layer. See MCP explained.

Merchant of record. The entity legally responsible for selling to the customer, handling payment, tax, refunds, and chargebacks. In ACP the merchant stays the merchant of record, so the agent surface does not take over the sale.

MPP (Machine Payments Protocol). Open standard co-authored by Stripe and Tempo, launched March 2026, for agents to pay services programmatically. A settlement-layer protocol for machine-to-machine microtransactions and recurring payments, settling in stablecoins as well as cards. Built on HTTP 402, like x402. See MPP explained.

P

Passkey. A FIDO-based, phishing-resistant credential tied to a user’s device, used to authenticate without a password. Mastercard’s Payment Passkeys apply the idea to confirm a user behind an agent-initiated payment.

Payment authorization (layer). The stack layer where the agent proves a real user approved a specific purchase, and where liability is settled. AP2 is the standard here. See the four layers.

Payment Mandate. In AP2, the signed record of what will actually be charged, shared with the payment network and issuer to signal agent involvement and that the user consented.

PSP (payment service provider). A company that processes payments for merchants (for example Stripe). In agentic checkout, the PSP often issues the payment token the agent passes to the merchant.

S

Settlement (layer). The stack layer where money actually moves, across card rails and machine-native options like x402 and MPP. See the four layers.

Shared Payment Token. In ACP, a single-use payment credential issued by the payment service provider and scoped to one specific merchant and one specific cart total. The agent passes it to the merchant to charge, and never sees the buyer’s raw card details. Also reused by MPP for card and buy-now-pay-later settlement.

Stablecoin. A cryptocurrency designed to hold a steady value against a reference such as the US dollar. Stablecoins (for example USDC) are the settlement medium for machine-native payment approaches like x402 and, optionally, MPP.

Streamable HTTP. MCP’s HTTP transport: a server exposes a single endpoint that accepts JSON-RPC over POST and can optionally stream responses with Server-Sent Events. It underpins remote MCP servers. See how to build a remote MCP server.

T

Tempo. The blockchain, incubated by Stripe with Paradigm, that MPP currently settles on, though MPP is designed to work across multiple rails.

Tokenization. Replacing sensitive payment details with a token, so an agent can transact without handling raw card numbers. The shared foundation under most network agent-payment products.

Trusted Agent Protocol. A Visa-led open framework, introduced October 2025, to help merchants distinguish legitimate AI agents from malicious bots when an agent arrives at a storefront.

U

UCP (Universal Commerce Protocol). Google’s standard for the broader shopping journey, from discovery through checkout to post-purchase. Launched January 2026; the main rival to ACP at the commerce layer. See UCP explained.

Universal cart. The idea of a single cart an agent can fill across multiple merchants.

V

Verifiable credential. A W3C standard for a tamper-evident, cryptographically signed digital claim. AP2 mandates are expressed as verifiable credentials, which is what lets a merchant or network check consent without trusting the agent.

X

x402. Coinbase’s settlement protocol reviving the HTTP 402 Payment Required status for machine-native, often stablecoin, payments. Contributed to the Linux Foundation’s x402 Foundation in 2026. Sits alongside MPP at the settlement layer.