Reference
Glossary
This glossary defines 32 mechanisms used across the directory. Each term has one public source, a last verified date, and the listings that use the term. Definitions describe the mechanism. The newest verification date among the terms is 2026-10-17. Related terms link in both directions.
Last verified 2026-10-17
- A2AOpen protocol, hosted by the Linux Foundation, for agents to discover each other through Agent Cards and collaborate over HTTP. Requests and responses use JSON-RPC 2.0.
- Agent CardJSON document in A2A that lists an agent's identity, capabilities, endpoint, skills, and authentication requirements so a client can decide how to call it.
- Agent identityAn identity created for an agent so access policy, risk checks, and audit logs can apply to it. Microsoft Entra Agent ID creates these identities from blueprints.
- Agent mandateSigned credential in AP2. A checkout mandate records the cart negotiated with the merchant. A payment mandate authorizes a payment instrument against that checkout.
- Agent marketplaceA market where an agent can hire a specialized agent for a task and pay for the work, or list its own service for other agents to hire.
- Agent walletA wallet an agent can use to discover paid services and pay under a cap the operator set. Tempo Wallet lets an agent preview Machine Payments Protocol terms and pay under a max spend cap.
- Agentic Commerce ProtocolOpen standard for an agent to browse a catalog, run a checkout session, and pass a delegated payment to a business.
- AGNTCYOpen stack, hosted by the Linux Foundation, for cross vendor agent discovery, identity, messaging, and observability.
- AP2Open payment extension for A2A and the Universal Commerce Protocol. It records checkout and payment authorization as signed mandates. Public samples exist while FIDO continues the standards work.
- Compute marketplaceA market where independent providers offer compute for workloads. Akash Network documents providers bidding to host those workloads.
- Content-addressed proofA CLP proof bundle that binds signatures, authorization, and payment events into a content-addressed record for an asset or capacity transaction.
- Decentralized identifierA URI that associates a subject with a DID document. The controller can prove control without permission from a centralized registry, identity provider, or certificate authority.
- Digital commodityWork product of an open network where independent subnets produce digital commodities and the chain pays contributors.
- ERC-8004Draft Ethereum proposal for three registries: an ERC-721 identity that points at an agent registration file, a reputation registry, and a validation registry.
- GuardrailProgrammable check that can block, alter, or validate user input, model output, or a tool call. NeMo Guardrails runs these checks as rails around an LLM application.
- HTTP 402HTTP status code 402, Payment Required. RFC 9110 reserves the code for future use. x402, L402, and the Machine Payments Protocol use a 402 response as the signal that the request needs payment.
- Human approvalA pause where a person inspects or changes agent state before the run continues. LangGraph provides this inside the graph.
- JSON-RPCStateless remote procedure call protocol. A request is a JSON object naming a method, with optional parameters and an id, and the server returns a JSON result or error.
- KYAPaySigned token from Skyfire that binds an agent identity to a payment the buyer has committed. The seller charges the token after delivery.
- L402HTTP 402 flow from Lightning Labs. The server returns a macaroon and a Lightning invoice. The client pays, then presents the preimage so the server can check payment without a lookup.
- Machine Payments ProtocolOpen HTTP 402 protocol, co-authored by Stripe and Tempo, so an agent can authorize payment for an API with a card or a stablecoin and receive a receipt.
- Model Context ProtocolOpen protocol that connects an LLM application to external tools, resources, and prompts. Hosts, clients, and servers exchange JSON-RPC 2.0 messages.
- Multi agentMore than one agent collaborating under a runtime. CrewAI pairs event driven Flows for control flow with Crews of role based agents that share a delegated task.
- PACTProtocol on A2A 1.0 that lets a personal agent sign its requests and act for a user only inside scopes that user approved with a brand.
- Payment facilitatorA service that verifies a payment and settles it for the seller. In x402 the server asks the facilitator to verify, does the work, then asks the facilitator to settle.
- Personal Agent ProtocolDraft protocol for a company to publish how a personal agent may sign in and act on a person's account, using OAuth, OpenAPI, and MCP.
- Policy engineSoftware that returns a decision from policy code, separate from the application that enforces it. Open Policy Agent evaluates structured input against Rego policy.
- Spend limitA budget on model calls. LiteLLM Proxy enforces personal, team, and agent spend budgets when a database is connected.
- Tool callA function an MCP server exposes for a model to execute. The MCP specification treats a tool as code execution and says hosts must get explicit user consent before invoking one.
- Universal Commerce ProtocolOpen commerce protocol so agents, businesses, and payment providers can negotiate checkout and identity linking over REST, MCP, or A2A.
- Web Bot AuthMethod for an automated client to sign HTTP requests so a site can verify which bot or agent sent them. The signature rules are still an IETF draft.
- x402Open standard for per request HTTP payments. The server quotes a price, the client sends the request again with proof of payment, and a facilitator can verify and settle it.