Glossary
AdCP (Ad Context Protocol)
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AdCP is an open protocol, launched on 15 October 2025 and governed by AgenticAdvertising.org, that defines the tasks AI agents use to discover sellers, plan and buy media, activate signals, build creative and verify brands, transported over Anthropic's Model Context Protocol or the Agent2Agent protocol.
The founding members were PubMatic, Scope3 (renamed Apostra on 23 September 2026), Swivel, Triton Digital, Optable and Yahoo, with 23 supporting organizations at launch and 154+ members claimed by the steward in October 2026 (PPC Land, 16 October 2025; AgenticAdvertising.org, accessed 17 October 2026). AgenticAdvertising.org describes itself in the protocol repository as a pending 501(c)(6) trade association with four equally weighted voting classes; the repository is licensed Apache 2.0 and the Prebid community maintains the reference sell-side implementation (adcontextprotocol/adcp on GitHub, accessed 17 October 2026).
Versions: 2.0.0 at launch; 3.0.0 GA on 22 April 2026 with brand.json, adagents.json, 20 planning channels, proposals and a mandatory idempotency_key; 3.1.0 GA on 18 June 2026; 2.x fully deprecated on 1 August 2026; 3.2.1 GA on 30 September 2026 with cross-package frequency caps and Reliable Reporting 1.0 (experimental); 4.0 targeted for early 2027 (AdCP release notes; AdCP versions page). Agents negotiate wire versions at release precision ("3.1", "3.2"). AdCP does not change the bid request; its buys execute on existing deal and order rails, which is why Optable's summit recap describes it as parallel to OpenRTB (Optable, 4 June 2026).
Example (task names from the 3.x line): get_adcp_capabilities → get_products (returns proposals) → create_media_buy with an idempotency_key → get_media_buy_delivery; creative is handled by build_creative and sync_creatives.
Related: AAMP, agentic advertising, programmatic guaranteed, curation.
Source: AgenticAdvertising.org, AdCP specification and release notes.