48 defined concepts
The language of agentic payments.
A shared vocabulary for authority, credentials, protocols, rails, settlement, and recourse. Definitions are written to expose system boundaries—not hide them behind acronyms.
A
- Agentic commerce
- Commerce in which an AI agent adaptively participates in discovery, evaluation, checkout, purchase, or post-purchase operations for a principal.
- Agentic payment
- A payment that an AI agent prepares, authorizes, initiates, or completes under delegated constraints for a person or organization.
- Agent recognition
- Verification that a request came from a registered or otherwise trusted agent, distinct from proving the transaction is authorized.
- AP2
- Google’s Agent Payments Protocol, focused on cryptographically signed mandates and payment accountability across agents and payment participants.
- A2A
- Agent2Agent Protocol, an interoperability model for agents communicating and coordinating work.
- ACP
- Agentic Commerce Protocol, a commerce flow for catalogs, checkout operations, and agent-mediated transactions.
- Agentic token
- Mastercard terminology for tokenized payment credentials associated with registered agents and constrained commerce authority.
P
- Principal
- The person or organization whose authority and economic interest the agent represents.
- Policy engine
- A deterministic service that evaluates a proposed transaction against mandates, budgets, merchant rules, risk signals, and organizational controls.
- Programmatic wallet
- A wallet service that software can invoke through policy-controlled signing rather than manual user interaction.
- Payment challenge
- A machine-readable response that states the price, accepted scheme, destination, network, and other requirements for access.
- Payment receipt
- Evidence of payment authorization or settlement, which must still be connected to merchant order and fulfillment state.
I
- Intent
- The principal’s goal and constraints before they are normalized into enforceable policy.
- Intent mandate
- An artifact that records the principal’s requested outcome and boundaries before a specific transaction is selected.
- Idempotency key
- A stable identifier that lets a server recognize retries of the same intended financial action and avoid duplicate effects.
M
- Mandate
- A verifiable statement of authority that defines what an agent may do, under which constraints, and for how long.
- MPP
- Machine Payments Protocol, an HTTP payment negotiation approach supporting multiple payment methods and payment sessions.
- MCP
- Model Context Protocol, a tool and resource interoperability protocol; it is not a payment rail by itself.
T
- Transaction mandate
- An authorization artifact bound to an exact merchant, order, amount, currency, terms, and expiry.
- Transaction binding
- Cryptographic or deterministic linkage between authority and the exact seller, order, amount, currency, terms, and expiry.
- Technical finality
- The point at which a rail considers a transaction confirmed or irreversible under its own rules.
- Trusted Agent Protocol
- Visa’s framework for signed, verifiable agent requests and merchant recognition in agentic commerce.
H
- Human-present flow
- A flow where the principal reviews or approves the final transaction while it is being executed.
- HTTP Message Signature
- A signature over selected HTTP message components, standardized in RFC 9421 and used by emerging agent-recognition approaches.
- Human in the loop
- A designed approval or intervention point for consequential, ambiguous, or high-risk agent actions.
D
- Delegated flow
- A flow where the agent acts under a previously granted, bounded mandate without interrupting the principal for every transaction.
S
- Step-up approval
- Additional principal authentication or confirmation required when risk, ambiguity, or transaction impact crosses a threshold.
- Scoped credential
- A payment or signing capability limited by seller, amount, currency, purpose, time, or transaction.
- Stablecoin
- A token designed to track a reference asset such as a fiat currency; its use does not remove custody, compliance, liquidity, or accounting obligations.
- Shared Payment Token
- Stripe’s seller-scoped, amount- and time-limited credential for passing payment authority from an agent to a business.
- Settlement
- The movement and final accounting of value on a payment rail, distinct from merchant fulfillment and user satisfaction.
C
- Credential service
- An isolated component that grants tokens or signs payment payloads only after an approved policy decision.
- Commercial finality
- The point at which the business outcome, recourse, fulfillment, and refund obligations are resolved—not merely the technical settlement point.
- Compensating transfer
- A new transfer used to return value after an irreversible push payment, rather than reversing the original transaction.
- Custody
- Control of assets or private keys; architecture and regulatory obligations change materially depending on who holds that control.
R
- Replay attack
- Reuse of a previously valid signed request or payment credential outside its intended one-time context.
- Reconciliation
- The process of comparing internal transaction state with merchant, processor, bank, facilitator, or blockchain records and repairing gaps.
- Rail
- The network and operational system that authorizes, clears, and settles value, such as cards, bank payments, or blockchains.
X
- x402
- An open protocol that uses HTTP 402 challenges and signed onchain payment payloads for programmatic resource access.
U
- UCP
- Universal Commerce Protocol, a commerce layer for capabilities and order or checkout state.
F
- Facilitator
- In x402, an optional service that verifies signed payment payloads and submits settlement so a resource server need not run chain infrastructure.
- Fail closed
- A control posture that denies or pauses execution when required identity, authority, policy, or verification evidence is missing.
N
- Network token
- A payment credential that substitutes for a primary card account and can carry domain, device, merchant, or agent constraints.
W
- Web Bot Auth
- An emerging signed-request approach for authenticating automated clients at web infrastructure and merchant boundaries.
O
- Order snapshot
- An immutable or hashed representation of seller, items, total, currency, fees, terms, and expiry presented for authorization.
E
- Evidence ledger
- A durable record joining intent, mandate, policy decision, credential, payment, fulfillment, refund, and dispute references.
K
- KYT
- Know Your Transaction screening that evaluates wallet or transaction risk, often used alongside sanctions and compliance controls.
B
- Blast radius
- The maximum potential impact of a compromised agent, credential, mandate, or policy configuration.
Put the terms in context