A
Account A billing relationship between a buyer and a seller. The account determines rate cards, payment terms, and billing entity. An agent may have access to multiple accounts (e.g., an agency managing accounts for different clients). See Accounts and Agents. Account Type Classification of MCP session credentials as either “platform” (aggregator) or “customer” (direct advertiser/agency). Audience (AdCP context) A named group of users uploaded by a buyer for targeted advertising. Distinct from signals: audiences are buyer-owned first-party CRM data uploaded viasync_audiences; signals are third-party data discovered via get_signals. Audiences are account-scoped — an audience_id cannot be used across sellers. Reference audiences in targeting_overlay.audience_include or audience_exclude in create_media_buy. See also Audience Member and Hashed Identifier.
Audience Member
A hashed identifier record representing one person in a CRM audience. Contains at least one of: hashed_email, hashed_phone, or uids. All PII is normalized and hashed (SHA-256) by the buyer before transmission — the protocol never carries cleartext personal data. Providing multiple identifiers for the same person improves match rates. See Hashed Identifier and UID.
Audience Constraints
Plan-level include/exclude rules that structurally prevent prohibited targeting patterns. Each constraint is an Audience Selector. The governance agent evaluates check_governance requests against these constraints to detect prohibited targeting before any ad is served.
Audience Selector
A discriminated union describing one targeting criterion — either a signal reference (pointing to a specific data provider signal) or a natural language description. Audience selectors appear in plan audience constraints and planned_delivery.audience_targeting.
Action Source
Where an event physically occurred: website, app, in_store, phone_call, chat, email, offline, system_generated, or other. Set on each event in log_event and declared at the product level in conversion_tracking.action_sources.
Activation
The process of making a signal available for targeting on a specific platform and seat.
Ad Context Protocol (AdCP)
An open standard for AI-powered advertising workflows. AdCP defines domain-specific tasks and schemas that work over MCP and A2A as transports, enabling natural language interfaces for advertising operations.
Agentic Commerce Protocol (ACP)
An open standard developed by OpenAI and Stripe for programmatic commerce flows in AI assistants. ACP defines how agents can initiate checkout, delegate payment, and complete transactions without becoming the merchant of record. In the context of Sponsored Intelligence, ACP handles the transaction after a brand agent hands off a user with purchase intent.
Agentic eXecution Engine (AXE)
Deprecated. The original real-time execution layer for impression-time targeting decisions. Replaced by the Trusted Match Protocol (TMP), which adds structural privacy separation and multi-surface support. See AXE documentation for legacy reference.
AgenticAdvertising.org
The member organization that stewards the Ad Context Protocol (AdCP) and related open standards for AI-powered advertising.
Agent (AdCP Context)
The authenticated entity making API calls—may be a brand’s internal team, an agency’s trading desk, or an automated buying system. Identified by the authentication token. Distinct from “Sales Agent” (the MCP server exposing inventory) and “AI Agent” (the AI assistant). See Accounts and Agents.
B
Budget Total monetary allocation for a media buy, which can be distributed across multiple packages.C
Context Match TMP operation that evaluates available packages against content context. Contains artifact IDs, context signals (topics, sentiment, keywords, embedding), and available packages. Carries no user identity. See Trusted Match Protocol. Conversion Tracking The mechanism for sending buyer-side marketing events to a seller for attribution. Involves two steps: configure event sources on the seller account (sync_event_sources), then send events (log_event). Seller-level capabilities (supported event types, UID types, attribution windows) are declared in get_adcp_capabilities; product-level support is declared in product.conversion_tracking. See also Event and Optimization Goal.
CPC (Cost Per Click)
Pricing model based on cost per click on the advertisement.
CPCV (Cost Per Completed View)
Pricing model based on cost per 100% video or audio completion.
CPM (Cost Per Mille)
Pricing model based on cost per thousand impressions. Traditional display advertising pricing.
CPP (Cost Per Point)
Pricing model based on cost per Gross Rating Point (GRP), commonly used in TV and audio advertising.
CPV (Cost Per View)
Pricing model based on cost per view at a publisher-defined threshold (e.g., 50% video completion).
Completed View
A video or audio ad that has been viewed to 100% completion. Used for CPCV pricing and completion rate metrics.
Completion Rate
The percentage of video or audio ads that are viewed to 100% completion (completed_views / impressions).
Customer Account
Direct advertiser or agency account with specific seat access and negotiated rates.
D
Data Provider An organization that owns and publishes audience or contextual data (e.g., Polk, Experian, Acxiom). Data providers publish signal catalogs via/.well-known/adagents.json on their domain, enabling discovery and authorization verification. See Data Provider Guide.
Data Provider Domain
The domain where a data provider publishes their signal catalog (e.g., polk.com). Used in signal_id objects to reference signals: { "data_provider_domain": "polk.com", "id": "likely_tesla_buyers" }.
Daypart
Specific time-of-day segment for time-based advertising, commonly used in DOOH (e.g., morning_commute, evening_prime, overnight).
Deployment (Signals Protocol)
The availability status of a signal on specific platforms, including activation state and timing.
Devices (Signals Protocol)
Size unit representing unique device identifiers (cookies, mobile IDs) - typically the largest reach metric.
Device Type (Media Buy Protocol)
Targeting and reporting dimension for device form factors: desktop, mobile, tablet, ctv, dooh, unknown. Complements device platform (operating system) with hardware classification.
Decisioning Platform
Technical infrastructure that selects which ad to serve at impression time. Receives activated signals and executes campaigns. Examples: DSPs (The Trade Desk), SSPs (Index Exchange, OpenX, PubMatic), ad servers (Google Ad Manager, Kevel).
DOOH (Digital Out-of-Home)
Digital advertising displayed on screens in public spaces such as billboards, transit stations, airports, and retail locations. Uses CPM or flat_rate pricing with parameters for SOV, duration, and venue targeting.
DSP (Demand-Side Platform)
A type of decisioning platform that allows advertisers to buy advertising inventory programmatically.
E
Event A marketing event logged vialog_event for attribution and optimization. Covers the full funnel from engagement (page_view, view_content, search) through intent (add_to_cart, initiate_checkout) to conversion (purchase, lead, complete_registration). Each event has an event_id (for deduplication), event_type, event_time, and optional user_match and custom_data. Defined in the event.json schema.
Event Source
A configured data channel that receives conversion or marketing events from a buyer. Event sources are set up on a seller account via sync_event_sources and referenced by event_source_id when logging events or setting optimization goals. Can be managed by the buyer (e.g. a website pixel) or by the seller (e.g. Amazon sales attribution).
Event Type
A standardized classification for marketing events (e.g. purchase, lead, add_to_cart, page_view, refund). Covers the full lifecycle: engagement (select_content, share), e-commerce (add_to_cart, remove_from_cart, viewed_cart, purchase, refund), lead management (lead, qualify_lead, close_convert_lead, disqualify_lead), and app events. Used to categorize events logged via log_event and to specify optimization goals on packages. Aligned with IAB ECAPI.
Estimated Activation Time
Predicted timeframe for signal deployment, typically 24-48 hours for new activations.
F
Flat Rate Fixed-cost pricing model where a single payment is made regardless of delivery volume. Common for sponsorships and takeovers. Flight A time-bounded advertising campaign segment, mapped to line items in ad servers. Frequency The average number of times an individual is exposed to an advertisement during a campaign.G
GRP (Gross Rating Point) A unit of measurement for television and radio advertising representing 1% of the target audience. Used in CPP pricing models. Total GRPs = Reach % × Average Frequency. Measured by third-party providers such as Nielsen, Comscore, iSpot.tv, or Triton Digital.H
Hashed Identifier Buyer-normalized personally identifiable information (PII) hashed with SHA-256 before transmission. Used in audience uploads (sync_audiences) and event attribution (log_event). Normalization: emails to lowercase+trim, phone numbers to E.164 format. The seller matches by independently hashing its own user data with the same algorithm — neither party shares raw PII. Distinct from UIDs, which are already-resolved privacy-preserving tokens from identity graphs.
Households
Size unit representing unique household addresses, useful for geographic and family-based targeting.
Human-in-the-Loop (HITL)
Protocol feature allowing publishers to require manual approval for operations.
I
Identity Match TMP operation that evaluates user eligibility against package criteria using an opaque user token. Returns a booleaneligible flag and optional intent_score per package. Carries no page context. The buyer computes eligibility from frequency caps, audience membership, and other signals; the reasons are opaque to the publisher. See Trusted Match Protocol.
Impressions (Media Buy Protocol)
The number of times an ad is displayed, used for pricing and delivery tracking.
Individuals (Signals Protocol)
Size unit representing unique people, best for frequency capping and demographic targeting.
Inventory
Available advertising space on websites, apps, or other media properties.
L
Line Item The basic unit of inventory in ad servers like Google Ad Manager, represented as packages in AdCP. Loop Duration The length of time for a complete rotation of ads in a DOOH display, measured in seconds. Used to calculate frequency and share of voice. Loop Plays The number of times an ad was displayed in a DOOH loop rotation. Key metric for DOOH delivery reporting.M
Marketplace Signal Third-party signal available for licensing from data providers. MCP (Model Context Protocol) The underlying protocol framework that enables AI assistants to interact with external systems. Media Buy A complete advertising campaign containing packages, budget, targeting, and creative assets.N
Natural Language ProcessingThe AI capability that allows audience discovery through conversational descriptions rather than technical parameters.
O
Offer (TMP) A buyer’s response to a TMP context match request. Ranges from simple activation (package_id only, for GAM key-value targeting) to rich proposals with brand, price, summary, and inline creative manifest (for AI assistants and dynamic surfaces). See TMP Specification.
Optimization Goal
A single entry in a package’s optimization_goals array. Two kinds: kind: "event" (optimize for advertiser-tracked conversion events via an event_sources array of source-type pairs, with optional cost_per, per_ad_spend, or maximize_value target) and kind: "metric" (optimize for a seller-native delivery metric — clicks, views, completed views, engagements, attention, etc. — with optional cost_per or threshold_rate target). Event goals with per_ad_spend or maximize_value targets require value_field on event source entries. When the seller supports multi_source_event_dedup (declared in get_adcp_capabilities), they deduplicate by event_id across sources; otherwise buyers should use a single event source per goal. When multiple goals are present, priority (1 = highest) controls which the seller treats as primary.
Owned Signal
First-party signal data belonging to the advertiser or platform.
P
Package A specific advertising product within a media buy, representing a flight or line item with its own pricing and targeting. Platform Account Master account representing an advertising platform that can syndicate signals to multiple customers. Policy Category A regulatory regime that applies to a campaign plan (e.g.,children_directed, fair_housing, fair_lending, fair_employment). Each policy category defines restricted_attributes — personal data types that must not be used for targeting when that category applies. Governance agents resolve policy categories from both the plan and the brand’s compliance configuration.
Pricing Model
The method by which advertising inventory is priced and billed. AdCP supports CPM, CPC, CPCV, CPV, CPA, CPL, CPP, and flat rate models.
Pricing Option
A specific pricing model offered by a publisher for a product, including rate, currency, and parameters.
Principal
Deprecated term. See Account (billing relationship) and Agent (authenticated caller). Previously used to refer to the authenticated entity with its associated platform mappings. AdCP now splits these responsibilities: the Agent handles authentication and API access, while the Account handles billing, rate cards, and platform mappings.
Product
Advertising inventory available for purchase, discovered through natural language queries.
Prompt
Natural language description used to discover relevant signals (e.g., “high-income sports enthusiasts”, “premium automotive content”, “users in urban areas during evening hours”).
Provider
The company or platform that supplies signal data (e.g., LiveRamp, Experian, Peer39, weather services).
Q
Quartile (Video) Milestones in video ad viewing: Q1 (25% viewed), Q2 (50% viewed), Q3 (75% viewed), Q4 (100% complete). Used to measure video engagement.R
Reach The number or percentage of unique individuals exposed to an advertisement at least once during a campaign. Restricted Attribute A personal data category (e.g.,health_data, racial_ethnic_origin) that must not be used for targeting under one or more policy categories. Restricted attributes are defined at the registry level (GDPR Article 9 categories) and self-declared on signal definitions. Governance agents match restricted attributes structurally — if a signal carries a restricted attribute that a plan’s policy categories prohibit, targeting with that signal is denied.
Relevance Score
Numerical rating (0-1) indicating how well a signal matches the discovery prompt.
Relevance Rationale
Human-readable explanation of why an audience received its relevance score.
Revenue Share
Pricing model based on a percentage of media spend rather than fixed CPM.
S
Sales Agent An MCP server that exposes publisher inventory for discovery and purchase. Handles product discovery, media buy creation, and campaign management. Examples: Publisher ad servers exposing AdCP interfaces, sales house platforms. Seller The AdCP participant role that provides advertising inventory. A seller exposes products, accepts media buys, manages creative delivery, and (optionally) provides conversion tracking capabilities. In AdCP schemas, “seller” is the standard term for this role (not “platform”). The seller’s technical capabilities are declared viaget_adcp_capabilities.
Screen Time
Total duration an ad was displayed across all DOOH screens, measured in seconds. Used for DOOH delivery reporting.
Seat
A specific advertising account within a decisioning platform, typically representing a brand or campaign.
Segment ID
The specific identifier used for signal activation, may differ from signal_id.
Share of Voice (SOV)
Percentage of available ad inventory allocated to a specific advertiser in DOOH loops. Expressed as 0.0-1.0 (e.g., 0.15 = 15% SOV).
Signal Agent
A server (via MCP or A2A) that provides signal discovery and activation services. Enables natural language audience discovery and deploys signals to decisioning platforms. Can be private (owned by a single principal) or marketplace (licensing data to multiple principals). Signal agents are authorized by data providers via adagents.json to resell specific signals. Examples: LiveRamp, The Trade Desk, Peer39.
Signal Catalog
A collection of signal definitions published by a data provider via /.well-known/adagents.json. The catalog includes signal metadata (id, name, value_type, tags) and authorization declarations for signals agents. See Data Provider Guide.
Signal Definition
A single signal entry in a data provider’s signal catalog, containing: id (unique identifier), name (human-readable), value_type (binary, categorical, or numeric), and optional fields like description, tags, allowed_values, and range.
Signal Discovery
The process of finding relevant data signals (audiences, contextual, geographical, temporal) using natural language descriptions or structured ID lookup.
Signal ID
A structured identifier referencing a signal. Uses source as a discriminator with two variants: catalog signals reference a data provider’s published catalog (data_provider_domain + id, verifiable); agent signals are native to the signals agent (agent_url + id, trust-based). Example catalog signal: { "source": "catalog", "data_provider_domain": "polk.com", "id": "likely_tesla_buyers" }. Example agent signal: { "source": "agent", "agent_url": "https://liveramp.com/signals", "id": "custom_segment" }.
Signal Source
The origin type for a signal identifier: catalog (from a data provider’s published catalog, authorization verifiable via adagents.json) or agent (native to the signals agent, not externally verifiable). See Data Provider Guide.
Signal Tags
Tags used to group related signals within a data provider’s catalog. Enable efficient authorization (authorize “all automotive signals” rather than listing individual IDs). Tags must be lowercase alphanumeric with underscores/hyphens.
Signal Type
Classification of signals as “marketplace” (third-party), “owned” (first-party), “destination” (bundled with media), “contextual”, “geographical”, or “temporal”.
Signal Value Type
The data type of a signal’s values: binary (user matches or doesn’t), categorical (user has one of several possible values), or numeric (user has a score within a range). Determines the targeting expression format.
Size Unit (Signals Protocol)
The measurement type for signal size: individuals, devices, or households.
Sponsored Intelligence (SI)
An open standard for conversational brand experiences in AI assistants. Like VAST defines video ad serving, SI defines how to serve and interact with brand agent endpoints. SI handles the engagement; the Agentic Commerce Protocol (ACP) handles transactions. See SI Chat Protocol for details.
SSP (Supply-Side Platform)
A type of decisioning platform that helps publishers sell advertising inventory programmatically. SSPs connect to multiple demand sources and make ad selection decisions. Examples: Index Exchange, OpenX, PubMatic, Magnite.
T
Takeover Exclusive 100% share of voice placement on DOOH inventory for a specific time period. Priced as flat_rate with sov_percentage: 100. Third-Party Signal Signal data licensed from external providers, also known as marketplace signals. Time-Based Pricing Pricing structure based on duration (hourly, daily, or daypart) rather than impressions. Common in DOOH advertising using flat_rate model. TMP Router Infrastructure that fans out TMP requests to buyer agents and merges responses. A single binary with structurally separate code paths for context and identity. The router enriches requests (adding property registry IDs, signing), enforces privacy constraints (rejecting requests with identity data in the context path), and applies adaptive timeouts. See Router Architecture. Trusted Match Protocol (TMP) AdCP’s real-time execution layer. Determines which pre-negotiated packages should activate for a given impression using two structurally separated operations: Context Match (content fit, no user identity) and Identity Match (user eligibility, no page context). The publisher joins both responses locally. Works across web, mobile, CTV, AI assistants, and retail media. Replaces AXE. See Trusted Match Protocol.U
UID (Universal ID) An already-resolved, privacy-preserving user token from an identity graph. Used for cross-platform user matching. Distinct from Hashed Identifiers: UIDs are pre-resolved tokens (not raw PII); hashed identifiers are buyer-normalized PII hashed before sending. AdCP supports:rampid (LiveRamp RampID), id5 (ID5), uid2 (Unified ID 2.0), euid (European Unified ID), pairid (IAB Tech Lab PAIR), and maid (Mobile Advertising ID — IDFA/GAID). UIDs are accepted in audience uploads (sync_audiences → audience_member.uids) and event attribution (log_event → user_match.uids). Supported types vary by seller — check get_adcp_capabilities → audience_targeting.supported_uid_types.
Universal Commerce Protocol (UCP)
An open standard developed by Google with Shopify, Walmart, Target, and others for commerce in AI assistants. UCP defines primitives for checkout, payments, and fulfillment. Along with ACP (Agentic Commerce Protocol), UCP represents the commerce layer that complements AdCP’s advertising layer.
User Match
The set of identifiers on an event used to attribute it to ad delivery. Includes universal IDs (uids), hashed identifiers (hashed_email, hashed_phone — SHA-256, normalized before hashing), click_id (platform-specific click identifiers like fbclid, gclid), and optional client_ip + client_user_agent for probabilistic matching. At least one identifier is required.
Usage Reporting
Daily reporting of signal utilization for billing and optimization purposes.
V
Venue Physical location where DOOH advertising is displayed (e.g., airport terminal, transit station, retail store). Used for DOOH targeting and delivery reporting. Venue Package Named collection of DOOH screens across specific venues (e.g., ‘times_square_network’, ‘airport_terminals’). Used in DOOH pricing parameters.Acronyms
- ACP: Agentic Commerce Protocol
- AdCP: Ad Context Protocol
- API: Application Programming Interface
- AXE: Agentic eXecution Engine
- CPA: Cost Per Acquisition
- CPM: Cost Per Mille (thousand)
- DMP: Data Management Platform
- DSP: Demand-Side Platform
- ECAPI: Enhanced Conversions API (IAB Tech Lab)
- EUID: European Unified ID
- MCP: Model Context Protocol
- PII: Personally Identifiable Information
- ROAS: Return On Ad Spend
- RTB: Real-Time Bidding
- SI: Sponsored Intelligence
- SSP: Supply-Side Platform
- TMP: Trusted Match Protocol
- TTD: The Trade Desk
- UCP: Universal Commerce Protocol
- UID: Universal Identifier
- UTC: Coordinated Universal Time
Units and Measurements
Time Formats- All timestamps use ISO 8601 format (e.g., “2025-01-20T14:30:00Z”)
- Dates use YYYY-MM-DD format
- Activation times expressed as human-readable estimates (“24-48 hours”)
- All pricing in specified currency (typically USD)
- CPM expressed as cost per 1,000 impressions
- Revenue share expressed as decimal (0.15 = 15%)
- Counts expressed as integers
- Units clearly specified (individuals/devices/households)
- Dated with “as_of” timestamp for freshness
- Delivery counts by package
- Pacing metrics for optimization
- Dimensional breakdowns available
Error Codes Reference
Common error codes across all AdCP implementations:SEGMENT_NOT_FOUND: Invalid or expired segment IDACTIVATION_FAILED: Unable to complete activation processALREADY_ACTIVATED: Signal already active for platform/seatDEPLOYMENT_UNAUTHORIZED: Insufficient permissions for platform/seatBUDGET_EXCEEDED: Operation would exceed allocated budgetCREATIVE_REJECTED: Creative asset failed platform reviewINVALID_PRICING_MODEL: Requested pricing model unavailableRATE_LIMITED: Too many requests in time windowAUTHENTICATION_FAILED: Invalid or expired credentialsVALIDATION_ERROR: Request format or parameter errors