Agent2Agent

Agent2Agent (A2A) is an open protocol for inter-agent collaboration, introduced by Google as a complement to Anthropic's Model Context Protocol (MCP). While MCP focuses on connecting agents to external tools and information sources, A2A specifically enables a client agent to delegate tasks to and coordinate with remote agents that provide third-party capabilities—the client frames and communicates the task, while the remote agent executes it . The protocol supports persistent, long-running connections where agents can exchange messages, context, and replies until a task completes . Google positioned it among 25 AI updates unveiled in April 2025, alongside its Agent Development Kit (ADK) for building multi-agent systems . Per a 十字路口Crossing analysis at the time, A2A's significance will grow as the agent ecosystem matures, though the piece cautioned that with MCP infrastructure still developing and debates ongoing about what even qualifies as a true "agent" versus workflow automation, the protocol remained more relevant for researchers and technologists than for most developers in the near term .