AdCP terms are the names the Ad Context Protocol gives to the tasks, files and records that AI agents use to plan, buy, deliver and check advertising, and most of them describe one step in a media buy. Task names such as list_products, request_proposals and accept_proposal are calls one agent makes to another. Files such as adagents.json and brand.json tell agents who is allowed to sell what, and on whose behalf.

TL;DR: This glossary defines 30 AdCP terms in one sentence each, grouped by the stage of a buy they belong to, and links every definition to the AdCP documentation page it comes from. The definitions follow AdCP 3.2, which became generally available on 30 September 2026, with version 3.3 in beta. For the wider vocabulary of agentic advertising, see the Agentic Advertising Glossary, and for what the standard is and who publishes it, see What Is the AdCP Standard?

How should you read an AdCP glossary?

AdCP is easiest to read as a sequence rather than an alphabet, because each task hands its result to the next one. A buyer agent first asks a seller what it supports, then discovers products or requests proposals, buys or accepts, sends creatives and finally reads delivery. Governance and identity terms sit around that sequence and decide whether each step is allowed.

A worked example makes the order concrete. Alkimi is neutral on standards: it can work with agents built on AdCP or AAMP, and its Gym lets a buyer agent spar against counterparty agents on practice briefs before any real money moves. The first thing worth checking in a run like that is whether the agent calls these tasks in a sensible order and stops when a check says no, so the glossary below follows the same order.

Names written with underscores are tasks, the AdCP word for a single operation one agent asks another to perform. Version 3.2 also renamed part of the buying flow: the documentation marks get_products as deprecated for new integrations while keeping it fully supported throughout 3.x. It describes create_media_buy as the 3.x compatibility facade, with new integrations using buy_products or accept_proposal.

What are the core AdCP terms?

1. Ad Context Protocol (AdCP): An open standard, stewarded by the member organisation AgenticAdvertising.org, that defines advertising tasks and schemas which run over MCP and A2A as transports (AdCP glossary).

2. Sales agent: The agent that exposes publisher inventory for discovery and purchase, handling product discovery, media buy creation and campaign management (AdCP glossary).

3. Account: The billing relationship between a buyer and a seller, of which one agent may hold several, as an agency does when it manages accounts for different clients (Accounts and agents).

4. get_adcp_capabilities: The first call a buyer makes to a seller, which reports the seller's protocol support and capabilities across all AdCP protocols (get_adcp_capabilities reference).

What do the AdCP media buying terms mean?

5. Product: Advertising inventory a seller makes available for purchase, which buyers discover through natural language queries or structured criteria (AdCP glossary).

6. list_products: A side-effect-free task that returns a seller's published product offers against structured discovery criteria, and returns products only, never proposals (list_products reference).

7. request_proposals: A task that asks a seller to turn a brief, or product IDs returned by list_products, into one or more immutable draft media plans (request_proposals reference).

8. Proposal: A seller-authored draft media plan which, once committed, means the seller has locked its commercial terms and reserved its inventory until it expires (accept_proposal reference).

9. buy_products: The buyer-composed purchase path, which creates a media buy from products returned by list_products and accepts their published terms as they stand (buy_products reference).

10. accept_proposal: The single terminal action in the proposal flow, which accepts one committed proposal to create, amend or cancel a media buy (accept_proposal reference).

11. Media buy: A complete advertising campaign containing packages, budget, targeting and creative assets (AdCP glossary).

12. Package: A specific product within a media buy, representing a flight or line item with its own commercial terms and targeting (AdCP glossary).

13. get_media_buy_delivery: A reporting task that retrieves impressions, spend, pacing and dimensional breakdowns for a media buy, whichever way the campaign was created (get_media_buy_delivery reference).

What do the AdCP creative terms mean?

14. sync_creatives: A task that uploads and manages creative assets in a creative library, with bulk uploads and upsert semantics, used once a media buy exists because buy_products deliberately carries no creatives (sync_creatives reference).

15. build_creative: A task that generates, transforms or retrieves a creative manifest for a specific format, for example adapting an existing manifest to a different format (build_creative reference).

What do the AdCP identity terms mean?

Identity files answer the question a buyer agent should ask before anything else: is this counterparty who it claims to be? A longer explanation of the publisher side sits in What Is adagents.json?

16. adagents.json: A file a publisher hosts at /.well-known/adagents.json to declare its properties and authorise the sales agents allowed to sell them, which data providers also use to publish signal definitions (adagents.json spec).

17. brand.json: A file that lets a brand claim its identity and publish discoverable brand information, with five variants to suit different publishing models (brand.json spec).

What do the AdCP signals and audience terms mean?

18. Signal: A data segment used for targeting or measurement in a campaign, such as an audience, contextual or geographic attribute (Signals key concepts).

19. Audience: A named group of users that a buyer uploads from its own first-party CRM data through sync_audiences, which, unlike a signal, is scoped to one account and cannot be reused across sellers (AdCP glossary).

20. get_signals: A task that discovers signals from a description or a signal reference and returns their metadata together with where each one is deployed (get_signals reference).

21. activate_signal: A task that activates a signal for use on a specific platform or account and handles the whole activation lifecycle, which can take minutes to days (activate_signal reference).

What do the AdCP governance terms mean?

The AdCP governance overview states its principle in one line: "Responsibility cannot be delegated to software" (AdCP governance protocol). Campaign governance tasks are marked experimental in AdCP 3.2. How these checks escalate to people is covered in How Does AdCP Governance Check Budgets, Brand Safety and Human Approval?

22. Campaign governance: An independent review layer that validates each buy-side action against authorised plans, brand policies, budget limits and compliance requirements (Campaign Governance).

23. sync_plans: A task that pushes campaign plans to a governance agent, where each plan sets the budget limits, channels, flight dates, authorised markets and compliance policies used as the source of truth for validation (sync_plans reference).

24. check_governance: The validation gate called by both sides, the buyer's orchestrator to check an intended action before it reaches a seller and the seller to check what it will actually deliver (check_governance reference).

25. Human-in-the-loop (HITL): A protocol feature that lets publishers require manual approval for operations (AdCP glossary).

26. Content standards: A protocol for privacy-preserving brand suitability on ephemeral or sensitive content, such as AI-generated responses, that cannot leave a publisher's infrastructure (Content Standards).

27. Property list: A managed inclusion or exclusion list that combines fixed sets of properties with dynamic filters and is built for setup time rather than real-time bid decisions (Property list management).

What do the newer AdCP execution terms mean?

28. Trusted Match Protocol (TMP): AdCP's real-time execution layer, which decides which pre-negotiated packages activate for an impression through two separated operations, Context Match with no user identity and Identity Match with no page context (AdCP glossary).

29. Sponsored Intelligence (SI): An open standard for conversational brand experiences in AI assistants, defining how to serve and interact with brand agent endpoints much as VAST defines video ad serving (Sponsored Intelligence).

30. Idempotency key: A unique identifier attached to every mutating AdCP request, so that a retry with the same key and payload returns the cached response instead of, for example, creating a second media buy (AdCP glossary).

How do AdCP terms sit alongside other agentic standards?

AdCP is one of several standards describing how advertising agents work together. IAB Tech Lab's Agentic Advertising Management Protocols (AAMP) cover related ground with their own vocabulary, and many teams will meet both. A glossary for each standard helps buyers and sellers check that a term means the same thing on both sides of a deal.

Where do people stay in charge when agents speak AdCP?

The glossary describes a division of labour. Agents take on the parts of media buying people rarely enjoy, such as querying product feeds, reformatting creatives and pulling delivery reports, while people keep the judgement: setting the plan and approving the deals that matter. A common way to stage that is earned autonomy, in which an agent moves from Observe to Recommend, Draft, Human-approved action and finally Bounded automatic action.

Alkimi follows the same split and works with or without a DSP. Concourse benchmarks any buying agent without asking which standard it uses, and the Gym trains and spars agents regardless of protocol. The Marketplace is neutral, with humans keeping approval rights at the deal level and each agreed deal written to a DealSheet that both parties hold.

Frequently asked questions

What is the difference between list_products and request_proposals?

list_products returns a seller's published products only and has no side effects, so a buyer can browse without starting a negotiation. request_proposals asks the seller to author one or more draft media plans from a brief, which the buyer can then accept with accept_proposal.

Is get_products still part of AdCP?

Yes, get_products remains fully supported throughout AdCP 3.x, although the 3.2 documentation marks it as deprecated for new integrations. New integrations are pointed to list_products and request_proposals instead.

What does adagents.json do?

adagents.json is a file a publisher hosts on its own domain to list its properties and name the sales agents authorised to sell them. A buyer agent can read it to check that the agent offering inventory is entitled to sell it.

Does AdCP require a human to approve every buy?

No, human review under campaign governance is triggered by the plan, for example when an action exceeds the plan's reallocation threshold or the plan requires review. Campaign governance tasks are marked experimental in AdCP 3.2, so teams should check the current documentation before relying on them.

Which AdCP version do these definitions follow?

They follow AdCP 3.2, which became generally available on 30 September 2026 and is the current stable documentation. Version 3.3 is in beta, so some task details may change.

Who publishes the official AdCP glossary?

AgenticAdvertising.org stewards AdCP and publishes an official glossary in the AdCP documentation. This page selects 30 of those terms and links each one to its source page.