AdCP v3.0.0

AdCP 3.0 is the first stable release of the Ad Context Protocol. The headline change is a trust-surface overhaul: mandatory idempotency keys, RFC 9421 request signing, signed governance contexts, compliance-gated test vectors, and GDPR/EU AI Act invariants baked into the schema.

See Migration from rc.3, What's new in v3, or the full release notes.

Protocol tarball — 3.0.0.tgz below is signed with Sigstore cosign (keyless, bound to the Release workflow on main). To verify:

cosign verify-blob 3.0.0.tgz \
  --certificate 3.0.0.tgz.crt \
  --signature 3.0.0.tgz.sig \
  --certificate-identity-regexp 'https://github.com/adcontextprotocol/adcp/' \
  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com'

Expected SHA-256: 04481e277089bebe551d3dc1294faab56aa876a7c08e0f010a8ca6ba41a06af4

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See release notes for migration guidance, or prerelease upgrade notes for rc.3 adopters.

Breaking Changes — trust surface

• 43586d6, c1d2ff1: Require idempotency_key on all mutating requests; formalize seller declaration as discriminated oneOf (#2315, #2436, #2447). Every mutating task now requires an idempotency_key in the request envelope, matching ^[A-Za-z0-9_.:-]{16,255}$; AdCP Verified additionally requires a cryptographically-random UUID v4. Fresh key per logical operation; reuse only to retry a failed request with the identical payload.

  Sellers declare dedup semantics on get_adcp_capabilities as adcp.idempotency = { supported: true, replay_ttl_seconds: <1h–7d, 24h recommended> } OR { supported: false }. When supported: true, sellers respond replayed: true on exact replay, IDEMPOTENCY_CONFLICT when the same key accompanies a different payload, and IDEMPOTENCY_EXPIRED after the declared TTL. When supported: false, sending an idempotency_key is a no-op — the seller will NOT return conflict/expired errors, and a naive retry WILL double-process. Buyers must use natural-key checks (e.g., get_media_buys by buyer_ref) before retrying spend-committing operations against non-supporting sellers. Clients MUST NOT assume a default — a seller without this block is non-compliant.

  Since supported: true is a trust-bearing claim, buyers and conformance runners SHOULD probe by replaying with a deliberately-mutated payload — a conformant seller MUST return IDEMPOTENCY_CONFLICT. Sellers declaring supported: true MUST pass this probe in the baseline compliance storyboard before the declaration is considered verified.

• aaace06: Model IO approval at the task layer, not as a media-buy status (#2270, #2351). MediaBuy.pending_approval is removed. Approvals are now modeled as explicit approval tasks with their own lifecycle, state, and audit trail — decoupled from the media-buy state machine. Enables sales-guaranteed sellers to implement human-in-the-loop approval without overloading media-buy status semantics.

• e6dd73a: GDPR Art 22 / EU AI Act Annex III enforced as JSON Schema invariants (#2310, #2338). budget.authority_level enum is removed and replaced by two orthogonal fields: budget.reallocation_threshold (number ≥ 0, or reallocation_unlimited: true) for budget autonomy, and plan.human_review_required (boolean) for per-decision review under Art 22. Cross-field if/then rejects human_review_required: false when policy_categories contains fair_housing, fair_lending, fair_employment, or pharmaceutical_advertising, or when any resolved policy carries requires_human_review: true. revisionHistory is append-only; downgrading human_review_required requires a human_override artifact (≥20-char reason, email approver, 24h-fresh approved_at). eu_ai_act_annex_iii seeded as a registry regulation. data_subject_contestation on brand.json (and inline on brand-ref.json) satisfies Art 22(3) discovery.

• ec06d47, 31aab3a: Specialism taxonomy finalized (#2332, #2336). inventory-lists specialism renamed to property-lists. New collection-lists specialism split out as a sibling under governance. Account migration on specialism declarations complete — agents declare specialism ownership via the account surface. audience-sync already reclassified from governance to media-buy in #2300.

• 84b322c: Rename compliance taxonomy domains → protocols (#2300). /compliance/{version}/domains/ becomes /compliance/{version}/protocols/. supported_protocols value maps to compliance path via snake_case → kebab-case (e.g. media_buy → protocols/media-buy/). audience-sync reclassified from governance to media-buy to match its tool family. Compliance runner path resolution, index.json structure, and catalog documentation all reflect the rename.

Breaking Changes

• 80ecf76: Simplify capabilities model for 3.0 (#2143). Remove redundant boolean gates — object presence is the signal. Make table-stakes fields required.

  Removed fields:

  • media_buy.reporting (product-level reporting_capabilities is source of truth)
  • features.content_standards / features.audience_targeting / features.conversion_tracking (object presence replaces booleans)
  • content_standards_detail → renamed to content_standards
  • brand.identity (implied by brand protocol)
  • trusted_match.supported (object presence)
  • targeting.device_platform / targeting.device_type (implied by media_buy)
  • targeting.audience_include / targeting.audience_exclude (implied by audience_targeting)

  Required fields:

  • reporting_capabilities on every product (see product.json)

• a90700f: Revert geo capability flattening (#2157). Restore geo_countries and geo_regions (booleans) and geo_metros and geo_postal_areas (typed objects with additionalProperties: false) as primary capability fields. Remove flat array alternatives (supported_geo_levels, supported_metro_systems, supported_postal_systems) introduced in #2143.

• 95f1174: Media buy status lifecycle (#2034). Rename pending_activation → pending_start. Add pending_creatives status for approved buys with no creatives assigned. Add top-level compliance_testing: { scenarios: [...] } capability block (not a supported_protocols value) for declaring comply_test_controller support.

• 100b740: Move storyboards into the protocol as /compliance/{version}/ (#2176). Add specialisms field to get_adcp_capabilities with 21 specialisms across 6 domains (media-buy, creative, signals, governance, brand, sponsored_intelligence). Promote sponsored_intelligence from specialism to full protocol in supported_protocols. Rename broadcast-platform → sales-broadcast-tv, social-platform → sales-social. Merge property-governance + collection-governance into inventory-lists. Add status: preview marker for 3.1 archetypes (sales-streaming-tv, sales-exchange, sales-retail-media, measurement-verification). Publish per-version protocol tarball at /protocol/{version}.tgz for bulk sync. New enums/specialism.json and enums/adcp-domain.json.

• 07d82dd: Require account on update_media_buy for governance and account resolution parity with create_media_buy (#2179). Flatten preview_creative union schema into single object with request_type discriminant.

• b674082: Add GOVERNANCE_DENIED to standard error codes with correctable recovery (#2194). Make signal_id required on get-signals-response signal items. Add context and ext fields to all request/response schemas (governance, collection, property, sponsored-intelligence, content-standards).

• 60f2a9e: Generalize governance to all purchase types (#2014). Remove media_buy_id from governance schemas — governance_context is the sole lifecycle correlator. Add purchase_type field on check_governance and report_plan_outcome. Add budget allocations on plans for per-type budget partitioning. Audit logs group by governance_context instead of media_buy_id.

Minor Changes — trust surface

• 9e1b0eb: RFC 9421 request signing profile (optional in 3.0, mandatory under AdCP Verified) (#2323). Agents MAY sign mutating requests using RFC 9421 HTTP Message Signatures with Ed25519 over a canonicalized covered-component list (including method, target URI, content-digest, and protocol-level fields). Published test vectors (request-signing/positive/*, request-signing/negative/*) and a 15-step verification checklist (alg allowlist, keyid cap-before-crypto, JWKS resolution via SSRF-validated fetch, replay dedup via jti). sf-binary encoding pinned (#2341) and URL canonicalization tightened (#2343) so independent implementations produce bit-identical canonical inputs. Verifier guidance at docs/building/implementation/security.mdx; test vectors at static/compliance/source/test-vectors/request-signing/.

• 2e3ec71: Signed JWS governance_context (#2316). governance_context is a signed JWS produced by the governance agent and echoed by the buyer in the media-buy envelope. Sellers verify the signature using the governance agent's JWKS (resolved via sync_governance) and bind decisions to a specific buyer, plan, phase, and time. Replaces the opaque-string carrier from earlier 3.0 drafts. Enables sellers to reject stale or forged governance decisions without round-tripping to the governance agent. Fields: alg, typ, iss, sub, aud, phase, exp, iat, jti, plus governance-specific claims.

• f2918f4: Signed-requests runner harness contract (#2350, #2353). Compliance runner declares a signed_requests harness profile: given a seller endpoint and a signing keypair, the runner...

AdCP v3.0.0-rc.2

AdCP 3.0.0-rc.2

Second release candidate for AdCP v3.

Highlights

• Brand Protocol Rights Lifecycle: get_rights, acquire_rights, and update_rights for brand licensing
• Structured visual_guidelines on brand.json for generative creative systems
• Shows and episodes as first-class content dimensions on products
• ai_media channel for AI platform advertising
• Property governance integration via optional property_list filtering
• Campaign governance and policy registry: sync_plans, check_governance, report_plan_outcome, and get_plan_audit_logs for plan-level governance and shared policies
• Simplified account model with require_operator_auth determining auth/account behavior

Breaking changes since rc.1

See the full release notes and v3 overview for migration details.

Schemas

Available in dist/schemas/3.0.0-rc.2/.

Full changelog: https://github.com/adcontextprotocol/adcp/blob/main/CHANGELOG.md
Release notes: https://docs.adcontextprotocol.org/docs/reference/release-notes#version-300-rc2
What's new in v3: https://docs.adcontextprotocol.org/docs/reference/whats-new-in-v3

AdCP v3.0.0-rc.1

AdCP 3.0.0-rc.1

First release candidate for AdCP v3. This release includes all breaking changes and new features planned for v3 GA.

Highlights

• Keyword targeting — keyword_targets and negative_keywords with match types (broad/phrase/exact) and per-keyword bid prices for search and retail media
• Optimization goals redesign — optimization_goals array with discriminated union (metric or event kind), multi-goal priority ordering, and reach optimization with frequency bands
• Signal pricing models — Structured pricing_options array with three models: CPM, percent of media, and flat fee
• Dimension breakdowns — Opt-in reporting dimensions on get_media_buy_delivery: geo, device type, device platform, audience, placement, keyword
• Device type targeting — New device_type (form factor: desktop, mobile, tablet, ctv, dooh, unknown) distinct from device_platform (OS)
• Typed refinement — refine redesigned as typed change-request array with seller acknowledgment via refinement_applied
• AI provenance — provenance object with IPTC digital source types, C2PA references, and regulatory disclosures
• Creative compliance — required_disclosures, prohibited_claims, and disclosure positions on creative briefs
• Structured error recovery — recovery field (transient, correctable, terminal) and 18 standard error codes
• Agent ergonomics — fields projection, opt-in breakdowns, pre-flight capability filtering
• Geo proximity targeting — Travel time isochrones, radius, and GeoJSON geometry methods

Breaking changes since beta.3

See the full release notes and what's new in v3 for complete migration guides.

Schemas

Available at https://adcontextprotocol.org/schemas/v3/ (once deployed) and in dist/schemas/3.0.0-rc.1/.

Full changelog: https://github.com/adcontextprotocol/adcp/blob/main/CHANGELOG.md

AdCP v3.0.0-beta.3

AdCP 3.0.0-beta.3

Major Changes

• Brand Manifest: Structured tone guidelines (voice, attributes, dos, donts) and structured logo fields (orientation, background, variant, usage)
• Cursor-based pagination: Standardized across all list operations with shared pagination-request / pagination-response schemas

Minor Changes

• Account scoping for delivery and artifacts queries (account_id param)
• sync_accounts task, authorized_operators, and account capabilities
• Channel fields on property and product schemas
• CPA pricing model for outcome-based campaigns
• Conversion tracking with log_event and sync_event_sources
• TIME pricing model for sponsorship-based advertising
• Attribution window metadata in delivery responses
• Brand Protocol for discovery and identity resolution
• Commerce attribution metrics (new_to_brand_rate, roas)
• Creative delivery reporting with variant-level data
• Delivery forecasting with budget curves and daypart targeting
• Deprecate FormatCategory enum; type field now optional on Format
• reported_metrics on creative formats
• Geographic exclusion targeting fields
• preview_creative top-level format_id now optional
• product_selectors for commerce product discovery
• Signal Catalog for data providers
• Functional restriction overlays (age, device platform, language)
• Typed asset requirements schemas for all creative format asset types
• Universal macro enum with 54 standard macros

Patch Changes

• Replace real brand examples with fictional names (Acme Corp, Pinnacle Media, Nova Brands)

See PR #961 for full details.

AdCP v3.0.0-beta.1

AdCP 3.0.0-beta.1

This is the first beta release of AdCP 3.0, introducing major protocol enhancements for governance, capability discovery, and media channel taxonomy.

🚀 Highlights

• Media Channel Taxonomy - New standardized channel definitions replacing the previous enum
• Content Standards Protocol - Brand safety and suitability evaluation framework
• Property Governance Protocol - Feature-based property filtering for compliance
• Unified Capability Discovery - get_adcp_capabilities task for cross-protocol discovery
• Pricing Option Improvements - Better separation of hard constraints vs soft hints

Breaking Changes

Media Channel Taxonomy

Replaces channel enum values with 19 planning-oriented media channels:

• display, olv, social, search, ctv, linear_tv, radio, streaming_audio, podcast, dooh, ooh, print, cinema, email, gaming, retail_media, influencer, affiliate, product_placement

Pricing Options

• fixed_rate → fixed_price
• price_guidance.floor → top-level floor_price
• Removed is_fixed discriminator

Creative Management

• creative_ids → creative_assignments with optional weight/placement control

Product Filters

• required_features changed from string array to object with boolean properties

New Features

Content Standards Protocol

• list_content_standards, get_content_standards, create_content_standards
• calibrate_content - Collaborative dialogue for policy alignment
• validate_content_delivery - Batch validate delivery records

Property Governance

• Property list management (create_property_list, update_property_list, etc.)
• Feature-based filtering and validation

Capability Discovery

• get_adcp_capabilities - Protocol-level task for cross-protocol discovery
• Structured geo targeting with named systems (nielsen_dma, us_zip, etc.)
• Governance capability declarations

Resources

• Schemas: https://adcontextprotocol.org/schemas/v3/
• Documentation: https://docs.adcontextprotocol.org
• Migration Guide: https://docs.adcontextprotocol.org/docs/reference/migrating-to-v3

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For full changelog details, see CHANGELOG.md

v2.5.1

What's Changed

• Fix allOf + additionalProperties validation and add oneOf titles (#334)
• Remove defaults and example URLs from adagents.json (#335)
• Fix schema versioning to preserve released versions (#337)

See CHANGELOG.md for full details.

v2.5.0

See full release notes at https://github.com/adcontextprotocol/adcp/blob/main/CHANGELOG.md#250

Highlights

• Discriminated Union Types: Improved TypeScript code generation with explicit discriminator fields
• Extension Fields: and fields for custom data across protocol
• Atomic Response Semantics: Success XOR error pattern for safer operations
• Batch Preview Support: Preview 1-50 creatives in one API call
• Full Package Objects: Consistent responses from create/update operations

Full details in CHANGELOG.md

v2.1.0 - Asset Schema Simplification

AdCP v2.1.0 - Asset Schema Simplification

Major architectural improvements that eliminate schema duplication and clarify the separation between asset payloads and format requirements.

🎯 Key Changes

Removed asset_type from Creative Manifest Wire Format

• Asset payloads no longer include redundant type information
• Asset types determined by format specification via asset_id lookup
• Validation is now format-aware

Deleted Duplicate Asset Type Schemas

• Removed 11 duplicate schema files (/creative/asset-types/*.json)
• Eliminated 1,797 lines of duplicate code
• Registry now references /core/assets/ schemas directly
• Single source of truth for each asset type

Cleaned Up Core Asset Schemas

• Removed constraint fields that belong in format specifications:
  • vast-asset.json: Removed max_wrapper_depth
  • text-asset.json: Removed max_length
  • webhook-asset.json: Removed fallback_required

📖 Migration Guide

Schema References

- const schema = await fetch('/schemas/v1/creative/asset-types/image.json')
+ const schema = await fetch('/schemas/v1/core/assets/image-asset.json')

Creative Manifest Structure

{
  "assets": {
    "banner_image": {
-     "asset_type": "image",
      "url": "https://cdn.example.com/banner.jpg",
      "width": 300,
      "height": 250
    }
  }
}

Validation Approach

Old: Standalone asset validation

validate(assetPayload, imageAssetSchema)

New: Format-aware validation

const format = await fetchFormat(manifest.format_id)
const assetRequirement = format.assets_required.find(a => a.asset_id === assetId)
const assetSchema = await fetchAssetSchema(assetRequirement.asset_type)
validate(assetPayload, assetSchema)

🏗️ Architecture

Clear Separation of Concerns:

• Core asset schemas (/core/assets/) = Payload structure (what you send)
• Format specifications = All constraints and requirements

Validation Flow:

1. Extract format_id from manifest
2. Fetch format specification
3. For each asset, look up asset_id in format's assets_required
4. Validate asset payload against the type defined in format
5. Validate constraints from format's requirements field

✨ Benefits

✅ Single source of truth for each asset type
✅ Eliminated 1,797 lines of duplicate code
✅ Clear separation between payload and requirements
✅ Format-aware validation is more accurate
✅ Simpler maintenance and evolution
✅ No more confusion about which schema to reference

📦 What's Included

• Comprehensive migration guide in CHANGELOG.md
• Updated documentation with validation flow examples
• All tests passing with new architecture
• Backward compatibility guidance

🔗 Resources

• Full Changelog
• Asset Type Registry
• Documentation

👥 Contributors

• @brianokelley
• Claude Code AI Assistant

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Note: While this release includes breaking changes to schema structure, we're releasing as v2.1.0 (minor version) rather than v3.0.0 to maintain continuity during early protocol adoption.

AdCP v2.0.0 - Production Release

🎉 AdCP v2.0.0 - Production Release

This is the first production-ready release of the Advertising Context Protocol (AdCP), marking it as stable and ready for real-world implementation.

Highlights

🚀 Complete Protocol Suite

• 9 Media Buy Tasks for full campaign lifecycle management
• 3 Creative Tasks with AI-powered generation
• 2 Signals Tasks for first-party data integration
• Standard Formats Library with industry-standard creative formats

🏠 Enhanced Homepage

• Prominent v2.0.0 release banner
• Comprehensive Key Features section showcasing all capabilities
• Professional design with interactive elements

⚙️ Version Management Infrastructure

• Changesets for automated version management
• Simplified version sync (only 2 files to update!)
• Complete release workflow documentation

What's Included

Media Buy Protocol

• get_products - Discover advertising inventory with natural language
• create_media_buy - Launch campaigns across platforms
• sync_creatives - Synchronize creative assets
• list_creatives - Query creative library
• update_media_buy - Update campaign settings
• get_media_buy_delivery - Real-time performance metrics
• list_authorized_properties - Discover authorized properties
• provide_performance_feedback - Share performance outcomes
• list_creative_formats - Discover supported formats

Creative Protocol

• build_creative - AI-powered creative generation from briefs
• preview_creative - Generate visual previews
• list_creative_formats - Full format specifications

Signals Protocol

• get_signals - Discover available first-party signals
• activate_signal - Activate signals for campaigns

Protocol Infrastructure

• MCP (Model Context Protocol) support
• A2A (Agent-to-Agent) protocol support
• Async workflows with webhooks
• Human-in-the-loop approval system
• Comprehensive JSON Schema validation

Technical Details

• Schema Version: 2.0.0
• Standard Formats Version: 1.0.0
• Protocol Support: MCP, A2A
• Node Version: >=18.0

Documentation

Complete documentation is available at https://adcontextprotocol.org including:

• Protocol specification
• Task reference guides
• Integration guides for MCP and A2A
• Standard formats documentation
• Error handling documentation

Version Management

AdCP uses Changesets for version management. See RELEASING.md for the complete release workflow.

What's Next

Future releases will follow semantic versioning:

• Patch versions (2.0.x): Bug fixes and clarifications
• Minor versions (2.x.0): New features (backward compatible)
• Major versions (x.0.0): Breaking changes

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Ready to build with AdCP? Start at https://adcontextprotocol.org/docs/intro