A2A
The leading standard for agent-to-agent coordination: agents publish an Agent Card describing their skills, then negotiate and delegate tasks to one another.
- 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
Agent2AgentAgent-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
- 2026-04 verify-against-primary-at-build ↗ https://www.linuxfoundation.org/press/a2a-protocol-surpasses-150-organizations-lands-in-major-cloud-platforms-and-sees-enterprise-production-use-in-first-year
- launch_date
- 2025 verify-against-primary-at-build ↗ https://github.com/a2aproject/A2A
- 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
- —
- adoption_metric
- 150+ organizations, landed in major cloud platforms, enterprise production use within its first year (April 2026) source
- 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 const card = await fetch('https://remote.example/.well-known/agent.json').then(r => r.json()); // card.skills lists what the agent can do; open a task against card.endpoints
- agent_readiness_link
- agent-readiness/a2a
- layer_legacy
- agent