a2a-protocol-impl

Agent-to-Agent (A2A) protocol enables inter-agent discovery and delegation by standardizing communication. Agents publish cards at /.well-known/agent.json containing capabilities, authentication, and rate limits, allowing other agents to discover them via registry lookup and send tasks with streaming progress updates via SSE.

An agent card is a JSON schema published at /.well-known/agent.json that describes an agent's name, description, version, URL, provider, capabilities, authentication method, and rate limiting. It enables other agents to discover your capabilities and route tasks appropriately in a distributed system.

Post tasks to the /tasks/send endpoint with task details; the receiving agent streams progress via Server-Sent Events (SSE) with task_progress, task_artifact, and task_complete events, allowing real-time monitoring without polling.

Yes, A2A protocol supports multi-agent orchestration by enabling agents to discover each other via registry lookup, delegate tasks to capable agents, and coordinate execution across distributed services implementing the standardized A2A specification.

Agent cards require name, description, version, URL, provider, capabilities list, authentication details, and rate limiting configuration. This metadata allows other agents to determine if your agent can handle their tasks and how to communicate securely.