The A2A Protocol
As agents proliferate, they need to talk to each other. A2A (Agent-to-Agent), launched by Google in April 2025 and subsequently donated to the Linux Foundation, is an open standard enabling agents from different vendors (e.g., an OpenAI agent and a Claude agent) to collaborate securely.
A2A systems include:
- Agent Cards: Standardized metadata describing an agent's capabilities, skills, and contact endpoints.
- Tasks & Artifacts: Structured work items that agents exchange to coordinate actions securely.
- Agent Discovery: "Is there an agent on this network that can book a flight?"
- Capabilities Exchange: Agents share their JSON tool schemas.
- Handoffs: Transferring context and control from Agent A to Agent B.
💡 Key Insight: Think of MCP as Agent-to-Database/Tool, and A2A as Agent-to-Agent. Together, they form the full interoperability stack. Both are now governed by the Linux Foundation.