A2A
Agent2Agent connects independent agent systems through messages, tasks and results. See Chapter 7.
A2UI
A format for describing agent-generated interfaces. The Lab prototype discussed here uses v0.8 as its historical experiment snapshot. Distinct from A2A and AG-UI. See Chapter 9.
ACMI
Agentic Commerce Maturity Index. Organisational self-assessment across Operations, Discovery, Transactions and Fulfillment. It complements technical observations rather than replacing them. See Chapter 18.
ACP
Here, always the Agentic Commerce Protocol associated with OpenAI and Stripe. The initials are used differently elsewhere. Check full name, source and revision. See Chapter 8.
AG-UI
Agent User Interaction Protocol. Describes events exchanged between agents and interfaces and can make work state visible. See Chapter 9.
Agency
A service business connecting business needs, experience, architecture, implementation and operations. Coding agents change implementation costs and increase the importance of judgement, acceptance and maintenance. See Chapter 16.
Agent
Software pursuing a task and using tools. The mandate defines what its principal authorises; technical permissions determine which system functions it can access. See Chapter 1.
Agent identity
Verifiable association of a request with an agent or provider. This is separate from a customer’s consent to a particular purchase. See Chapter 8.
Agentic Commerce Alliance
Cross-provider collaboration supporting practical adoption of agentic commerce. Guidance, benchmarks, joint implementation and documented experience help merchants across Operations, Discovery, Transactions and Fulfillment. See Chapter 18.
Agentic operations
Agent use inside merchant operations, including preparation, analysis and bounded execution. See Chapter 11.
ANP
Agent Network Protocol. An approach to open agent networking. Suitability depends on its trust and operating model rather than the networking idea alone. See Appendix B.
AP2
Agent Payments Protocol. The protocol addresses demonstrable purchase and payment authorisation through mandates. It is not a payment network. See Chapter 8.
API
Application Programming Interface. A defined way for software to access information or functions. Existing APIs can underpin agent capabilities without containing AI themselves.
Approval
Internal authorisation of a described action, such as a price change or a purchase by the business. The book distinguishes this from a customer’s consent to a purchase.
ARD
Agentic Resource Discovery. An approach to describing and discovering resources across federated services. Distinct from the RFC 9727 API catalogue. See Chapter 9.
Assistant
The conversational presence a person interacts with on screen. It can employ agents that handle tasks and use tools behind the interface. See Chapter 1.
Attribution
Assigning outcomes to touchpoints or channels. It identifies involvement, not whether revenue would have disappeared without the channel. See Chapter 14.
Authority
The legal concept of permission to act. The book’s practical model distinguishes the mandate granted by a principal from technical access permissions. See Chapters 1 and 12.
AXP
Agentic Experience Protocol. A Lab prototype exploring product knowledge, quality signals and experience in other agent interfaces. See Chapter 6.
Baseline
An inspectable starting or comparison condition. Without it, additional improvement is difficult to establish.
Buyer agent
An agent representing a buyer’s goals and boundaries. Its interests differ from those of a seller’s agent.
Capability
A described function of an interface or system. A published capability is initially a claim or commitment; its usable effect must be verified.
Checkout
The process connecting a specific purchase with required information, conditions and payment. The visible interface is only part of it.
Coding agent
Software that plans development work, reads and changes code and uses tools. Reviewable changes and explicit access rights belong in its working environment.
Cognitive commerce
An operating model connecting business knowledge, agent work and controlled execution. It can support an objective-led operator. Chapter 11 describes the architecture and stages of development.
Commerce core
The shared commerce logic that processes offers, prices and orders authoritatively under the merchant’s business rules. Different interfaces use this foundation. See Chapters 1 and 10.
Commodity trap
See Kill-switch loop.
Consumer
The component actually using an output. A registered function without a connected consumer may exist without producing value.
Contribution
Revenue minus variable costs defined for the analysis. Always state included costs. Investment decisions require incremental contribution against a comparison case.
Customization
Adapting a system to a specific business need. Total cost includes integration, verification, operations and later updates. See Chapter 15.
Delegation
Assignment of particular tasks and authority. It does not automatically transfer all legal or organisational responsibility.
Discovery
Finding, understanding and shortlisting offers or capabilities through search, indexes, feeds or direct interfaces. See Chapter 5.
DPoP
An OAuth mechanism binding access to possession of a key. It reduces certain token attacks without replacing business authorisation. See Chapter 13.
Emotional value zone
A situation where experience, meaning or relationships create distinctive value. A presentation format alone does not demonstrate that value. See Chapter 6.
End-to-end
The full relevant path from assignment to observed effect. A successful intermediate step does not prove the complete process.
ERC-8004
A published blockchain-related draft for agent identity, reputation and validation. Payment processing is separate. See Appendix B.
Experience
The designed experience around a need: presentation, orientation, advice and interaction. It connects meaning to a dependable purchasable outcome. See Chapter 6.
Fulfilment
Delivery of the promised service or goods. Agentic purchasing does not remove the need to verify this physical or digital outcome.
GTIN and MPN
Identifiers helping distinguish products: Global Trade Item Number and Manufacturer Part Number. Variants and revisions may require additional distinctions.
Hallucination
An unsupported or factually incorrect model output. Not every system error is a hallucination; permission, pricing and retry problems need different repairs.
Human handoff
Transfer to a person with relevant context and a clear next step. Good handoffs minimise data and avoid repeated work.
Idempotency
Repeated processing of the same intended action does not create an additional effect. Particularly important after uncertain responses and timeouts.
Incrementality
Additional effect relative to a plausible comparison without the measure. Distinguishes newly created value from channel migration.
Kill-switch loop
A strategic model in which interchangeable offers face price and access pressure. Lower contribution limits investment in distinctive value, making the offer more interchangeable. Also called the commodity trap. See Chapter 20.
Knowledge graph
Connected information about products, attributes, sources, needs and relationships. States and access rules distinguish confirmed knowledge, proposals and private context. See Chapter 11.
Mandate
In this book, an explicitly bounded permission for later action. Individual protocols define their own technical mandate forms. General concept and specification must be distinguished.
MCP
Model Context Protocol. Shared interface for tools and context in AI applications. Business rules still require implementation. See Chapter 7.
MCP Apps
Extension supporting interactive interfaces associated with MCP tools and compatible hosts. Different from WebMCP. See Chapter 9.
Merchant agent
An agent acting for the seller’s offer and permitted commercial conditions. Negotiation must remain within actual authority.
Merchant of Record
The seller role responsible for a transaction under the relevant model. Examine contractual and payment arrangements rather than assuming one universal allocation.
MPP
Machine Payments Protocol. An approach to machine payments, particularly for web services. Complete commerce and fulfilment obligations remain additional concerns.
OAuth
A framework for controlled authorisation of access. Successful sign-in and permission for a specific action are different facts.
Offer
Specific conditions for a transaction: item, quantity, buyer context, amount, delivery and other commitments. A binding offer needs identity and validity. See Chapter 8.
Open source
Software licensed to permit use, study, modification and redistribution. Open interfaces and open model weights are separate questions. See Chapter 15.
Open weights
Accessible trained model parameters. Rights, training-data information and tooling depend on the licence and release. Access to weights alone does not automatically meet the Open Source AI Definition.
PACT
Personal Agent Consent and Trust Protocol from Decagon. An approach to explicit personal-agent authority built on A2A and OAuth.
Personal agent
Software acting for a person across individual purchases and service requests. When buying, it takes the buyer-agent role; its scope and permissions follow the relevant mandate. See Chapters 1 and 8.
Personal Agent Protocol (PAP)
Personal Agent Protocol, also called Poppy. Connects personal agents to companies through authentication, sessions and several access routes. The protocol passport records the draft examined here. See Chapter 8.
Policy
A rule governing permitted actions or conditions. Published policy requires enforcement at the execution boundary.
Prompt injection
An attempt to redirect a system through external content toward unauthorised or unrelated actions. Content must not acquire higher instruction authority.
Readiness
Preparedness for a defined purpose. Public readability, organisational maturity and tested execution are distinct forms. See Chapter 18.
Shared Payment Token
A constrained payment primitive enabling use of payment credentials for an authorised transaction. Scope and participation depend on the provider.
Shop operator
An agent with a defined area of operational responsibility. An objective-led operator pursues a persistent mandate within commercial and technical boundaries. See Chapter 11.
Storyfront
An experiment in narrative, interactive product experiences. Its documented integration uses the shared commerce core for authoritative prices, baskets and orders. See Chapter 6.
Surface
One field in the book’s strategic map: people or agents encounter an offer in the merchant’s shop or external channels. An interface is the particular screen or conversation. See Chapter 1.
System of Record
The authoritative system for a particular business fact. Product, offer, authority and transaction may have different systems of record.
Trust signal
Verifiable information about reliability, such as delivery history over a stated period. Provenance matters more than an unexplained aggregate number.
UCP
Universal Commerce Protocol. Shared models and capabilities for commercial interactions. The implementation determines what is usable. See Chapter 8.
User consent
A customer’s informed consent to a specific offer and its conditions. Internal approval of operational changes is treated separately.
VEYNDO
The author’s personal, publicly developed experimental environment for commerce with knowledge and agents at its core. It explores architectural ideas outside the compatibility constraints of an established platform. See Chapters 11 and 15.
WebMCP
An approach to explicit tools in a website’s browser context. Actual browser and agent support must be verified.
x402
A protocol family linking HTTP with payment requirements and proofs. Useful for machine-purchased services, but not an automatic substitute for every obligation of a goods purchase.