Glossary
Definitions for the vocabulary of agent-driven payments and the controls around them.
Brand
Axorum
A control-and-accounting layer that checks and records every payment an AI agent attempts, before it executes. It does not move money.
Category
Agentic commerce
Agentic commerce is commerce in which an AI agent initiates or completes a transaction on behalf of a person or an organization. It spans consumer purchasing through AI assistants and business-to-business flows where agents buy compute, data, and services from other systems.
Agentic Commerce Protocol (ACP)
A protocol backed by OpenAI and Stripe for purchases completed inside AI assistants.
Agent payments
Payments initiated by AI agents under delegated authority from a principal.
Agent spend control
Agent spend control is the enforcement of budgets and authority limits on transactions initiated by AI agents, applied at the moment the agent attempts to spend rather than during a later review. Controls typically cover how much, with whom, for what category, and how frequently.
AP2 (Agent Payments Protocol)
AP2 is a protocol for agent-initiated payments introduced by Google, built around a chain of mandates that carry proof of what a user authorized. It aims to give a payment recipient cryptographic evidence that an agent was permitted to transact on a principal's behalf.
Billing systems and accounting systems
Billing systems determine what a customer owes and produce invoices. Accounting systems record what occurred in balanced, immutable entries that support financial statements and audit. The two are frequently confused because both handle money and both produce numbers that appear in reporting.
Cross-rail reconciliation
Cross-rail reconciliation is the work of producing one authoritative set of books when value moves over several payment rails at once — cards, ACH, stablecoin transfers, and machine payment protocols. Each rail reports only its own share, so no rail's report shows the total position with any counterparty.
Mandate
A mandate is a delegation of spending authority from a principal to an agent, with defined scope and limits. It states who authorized the spending, what the agent may spend it on, up to how much, and for how long. Mandate is the central noun in agent payment protocols including AP2.
Preventive control and detective control
A preventive control stops an unwanted transaction before it occurs. A detective control identifies one after it has occurred. Both are standard categories in internal control frameworks. The distinction matters more for agent transactions than for human ones, because settlement is fast and often irreversible.
Spend management
The processes and tools for controlling and tracking an organization’s outgoing spend — purchasing, expenses, cards, and payables.
Sub-ledger
A sub-ledger is a specialized set of books that records transactions in detail for one part of a business and passes summarized entries to the general ledger. Accounts payable, payroll, and fixed assets are traditional examples. A machine-commerce sub-ledger does the same job for transactions initiated by software rather than people.
Universal Commerce Protocol (UCP)
A Google-backed protocol for agent-mediated commerce, supporting multi-item carts assembled inside an assistant and checked out with stored credentials.
Usage-based billing
Pricing based on metered consumption rather than a fixed subscription. The invariant that matters: billed should never exceed metered, and metered should never exceed consumed.
x402
x402 is an open protocol for machine payments over HTTP, built on the 402 status code. It allows a client to pay for a resource programmatically and retry, without human involvement. It originated at Coinbase and is now governed under the Linux Foundation.
Feature
Approval workflow
A process routing a transaction to designated reviewers before it proceeds. Built for human-paced volumes and human judgment.
Audit trail
The evidence chain showing what occurred, when, under whose authority, and what changed as a result. For agent transactions this includes the authorization the transaction drew against.
Payment orchestration
A layer above payment providers that routes transactions across them and consolidates the resulting data. Solves for provider resilience and coverage; the consolidated-data problem it addresses is closely related to cross-rail reconciliation.
Virtual card
A digitally issued card number, usually single-use or vendor-locked, with its own spending limit and controls.
Use case
AP automation
Software that streamlines accounts payable — invoice capture, matching, approval routing, and payment — with less manual work.
Procurement agent
An AI agent that sources, orders, and pays for goods or services on an organization’s behalf within a set mandate.
Informational
Accrual
Recording an expense or revenue in the period it was incurred or earned, regardless of when cash moved. The reason continuous machine settlement complicates period reporting.
Agent sprawl
The proliferation of agents across an organization faster than anyone is tracking them, and the resulting loss of visibility into what they can do and what they are spending.
AI agent
A software system that pursues a goal across multiple steps, choosing actions rather than following a fixed script. In a payments context, one that can initiate transactions.
ASC 606
The US standard governing revenue recognition, based on when performance obligations are satisfied rather than when cash is received or an invoice issued.
Cash application
Matching incoming payments to what they were for. Difficult at scale when payments arrive without remittance information, which is the normal case for machine-initiated settlement.
Counterparty
The other party to a transaction. For agent payments, one that may be another agent, and may not be a legal entity at all.
Deterministic replay
Re-running a sequence of operations from the same starting state and obtaining an identical result. Requires avoiding wall-clock reads, floating-point arithmetic, and iteration-order dependence.
Double-entry bookkeeping
The practice of recording every transaction as balancing debits and credits, in use since the fifteenth century. Its structure — an append-only journal producing derived balances — closely resembles what software engineering later named event sourcing.
Entity resolution
Entity resolution is the process of determining which real-world legal entity a counterparty corresponds to — the registered company, its jurisdiction, and its tax status — rather than only verifying that a request came from a particular key or account. Authentication proves control of a credential. Entity resolution answers who is on the other side.
Event sourcing
Storing state as an append-only sequence of events, with current state derived by replay.
General ledger
The complete set of accounts and balances for an entity, and the source of its financial statements. Sub-ledgers summarize into it.
HTTP 402 Payment Required
HTTP 402 is a status code reserved in the original HTTP specification for payment-related responses and left largely unused for three decades. Machine payment protocols have revived it: a server returns 402 to indicate a request requires payment, along with instructions the client can act on programmatically.
Idempotency
The property that applying an operation twice has the same effect as applying it once. Table stakes for payment APIs, usually implemented with client-supplied keys.
Internal control
A process providing reasonable assurance over reporting reliability, operational effectiveness, and compliance. Controls are commonly classified as preventive, detective, or corrective.
Journal entry
The atomic record of a transaction: two or more postings that sum to zero. Multi-line structure matters, because many real transactions involve more than two accounts.
Know your agent (KYA)
Verification practices applied to AI agents, by analogy to know-your-customer requirements. Establishes which agent is transacting; does not by itself establish the legal entity behind it.
Legal Entity Identifier (LEI)
A 20-character code identifying a legally distinct entity participating in financial transactions, issued under GLEIF governance. The verifiable variant, vLEI, extends this to cryptographically verifiable credentials.
Merchant of record
The party legally responsible for a transaction with the customer, including tax collection, chargebacks, and refunds. Agent-mediated checkout raises the question of who holds this role when the cart was assembled elsewhere.
Model Context Protocol (MCP)
An open protocol for connecting AI systems to external tools and data, originated by Anthropic and governed under the Linux Foundation.
Non-human identity (NHI)
Identity and access management for machine identities: service accounts, workloads, and agents.
Period close
The process of finalizing a reporting period so its figures stop changing: accruals booked, reconciliations completed, and the period locked.
Principal
The person or organization on whose behalf an agent acts, and the source of the authority the agent holds.
Reconciliation
Matching records across two systems to identify differences: bank to books, processor to ledger, sub-ledger to general ledger.
Refusal record
A refusal record is the durable evidence that a transaction was evaluated and declined. It captures what was requested, which rule refused it, and the state of the relevant budget or authority at that moment. Refusals are evidence of a working control, which makes them worth recording rather than discarding.
Segregation of duties
The control principle that no single party should both initiate and approve a transaction. Requires deliberate design when both parties are software operating under the same configuration.
Shadow ledger
A shadow ledger is a second record of financial activity that a system maintains alongside the authoritative books, usually to answer a question the authoritative books cannot answer quickly enough. Because the two records are updated separately, they drift, and the drift is typically discovered during reconciliation.
Trial balance
A report proving total debits equal total credits across all accounts. Traditionally produced periodically.
Unattributed exposure
Unattributed exposure is the cumulative amount transacted with a counterparty whose legal identity has not yet been established. It exists because identity resolution often completes after the first transaction rather than before it, which means an unknown counterparty can accumulate meaningful exposure before anyone can attribute it.
Unbilled revenue
Revenue earned but not yet invoiced. Common where delivery is continuous and billing is periodic.
Verifiable credential
A tamper-evident credential whose authorship can be cryptographically verified. Relevant because independently verifiable artifacts serve as audit evidence in a way that a vendor's internal assertion does not.