Agent-to-agent (A2A)
A2A is an open protocol for agents from different vendors to discover each other and delegate tasks. MCP connects agents to tools; A2A connects agents to agents.
Changes fast: check the latest updates too. Reviewed 17 Oct 2026.
Key ideas
- Agents publish an Agent Card describing skills, endpoint and auth.
- Work is exchanged as tasks with messages and artifacts, with streaming and push updates.
- Useful across organisational boundaries; inside one system, plain function calls or sub-agents are simpler.