{
  "dataset": "protocols",
  "record": {
    "id": "a2a",
    "name": "A2A",
    "full_name": "Agent2Agent Protocol",
    "layer": "interop",
    "creator": "Google (now under the Linux Foundation)",
    "status": "production (150+ orgs)",
    "source": "A2A project / Linux Foundation announcements, 2025–2026 (org count per project communications).",
    "year": 2025,
    "one_liner": "The leading standard for agent-to-agent coordination: agents publish an Agent Card describing their skills, then negotiate and delegate tasks to one another.",
    "spec_url": "https://a2a-protocol.org",
    "snippet": "GET /.well-known/agent.json → { \"name\": \"...\", \"skills\": [ ... ], \"endpoints\": { ... } }",
    "abbreviation": "A2A",
    "also_known_as": [
      "Agent2Agent",
      "Agent-to-Agent Protocol"
    ],
    "canonical_spec_url": "https://a2a-protocol.org",
    "entity_uri": "https://en.wikipedia.org/wiki/Agent2Agent",
    "taxonomy_layer": "interop",
    "sub_layer": "agent-to-agent",
    "protocol_type": "transport",
    "central_problem": "Lets independent AI agents on different platforms discover each other, advertise skills, and delegate or negotiate tasks across organizational boundaries.",
    "maintainer": "A2A project, hosted by the Agentic AI Infrastructure Foundation (AAIF) under the Linux Foundation",
    "governance_body": "AAIF",
    "license": "Apache-2.0",
    "maturity_tag": "production-ready",
    "current_spec_version": "v1.0",
    "spec_date": {
      "value": "2026-04",
      "verify_status": "verify-against-primary-at-build",
      "source_hint": "https://www.linuxfoundation.org/press/a2a-protocol-surpasses-150-organizations-lands-in-major-cloud-platforms-and-sees-enterprise-production-use-in-first-year",
      "note": "v1.0 announced around the protocol's one-year mark (Apr 2026 LF press); confirm the exact v1.0 spec date against the primary A2A/LF announcement at build."
    },
    "launch_date": {
      "value": "2025",
      "verify_status": "verify-against-primary-at-build",
      "source_hint": "https://github.com/a2aproject/A2A",
      "note": "Originally announced by Google in 2025; LF hosting since ~June 2025. Confirm exact first-release date at build."
    },
    "last_verified": "2026-06-15",
    "transport": "JSON-RPC / HTTP, with Server-Sent Events for streaming task updates",
    "core_mechanism": "Each agent publishes an Agent Card at a well-known URL describing its identity, skills, and endpoints; a client agent reads the card and opens a task with the remote agent, exchanging messages and artifacts over the task lifecycle until completion.",
    "discovery_endpoint": "/.well-known/agent.json (Agent Card)",
    "settlement_type": null,
    "adoption_metric": {
      "value": "150+ organizations, landed in major cloud platforms, enterprise production use within its first year (April 2026)",
      "source": "https://www.linuxfoundation.org/press/a2a-protocol-surpasses-150-organizations-lands-in-major-cloud-platforms-and-sees-enterprise-production-use-in-first-year",
      "last_verified": "2026-06-15"
    },
    "notable_adopters": [
      {
        "value": "Google",
        "source": "https://a2a-protocol.org"
      },
      {
        "value": "Major cloud platforms (per LF April 2026 press)",
        "source": "https://www.linuxfoundation.org/press/a2a-protocol-surpasses-150-organizations-lands-in-major-cloud-platforms-and-sees-enterprise-production-use-in-first-year"
      }
    ],
    "relationships": [
      {
        "predicate": "complements",
        "target": "mcp",
        "note": "A2A -complements-> MCP (research §2 seed triple): A2A is agent→agent, MCP is agent→tool."
      },
      {
        "predicate": "governed_by",
        "target": "aaif",
        "note": "A2A v1.0 housed by AAIF (research §2)."
      },
      {
        "predicate": "extends",
        "target": "ap2",
        "note": "AP2 is designed as an extension of A2A's task lifecycle for payments."
      }
    ],
    "ideal_use_case": "Multi-agent systems where agents from different vendors/teams must coordinate and delegate work.",
    "when_to_use": "When you need agents to talk to OTHER agents — discover skills, hand off tasks, and stream results across trust boundaries.",
    "when_not_to_use": "When a single agent just needs to call tools or read your site (use MCP or Layer-1 discovery files); A2A's agent-card + task machinery is overhead you don't need.",
    "code_example": "// Discover a remote agent's capabilities\nconst card = await fetch('https://remote.example/.well-known/agent.json').then(r => r.json());\n// card.skills lists what the agent can do; open a task against card.endpoints",
    "agent_readiness_link": "agent-readiness/a2a",
    "layer_legacy": "agent"
  }
}