# Agent2Agent Protocol (A2A) Agent2Agent (A2A) is an open protocol for agent-to-agent interoperability, introduced by Google in 2025 and later donated to the Linux Foundation. It lets independent [[AI Agents]], built by different teams on different frameworks, discover each other, exchange messages, and delegate tasks over a standard interface. Each agent publishes an Agent Card describing its identity and capabilities; others use it to decide what to hand off. ## How it fits with MCP A2A and the [[Model Context Protocol (MCP)]] are complementary, not competing: - **MCP** connects an agent to tools, data, and context (vertical: agent to capability) - **A2A** connects agents to each other (horizontal: agent to agent) - Discovery layers like the [[Agentic Resource Discovery Specification (ARD)]] sit above both, helping a client find which agent or tool to use in the first place It appears in agent platforms such as the [[MCP Gateway Registry]] (agent registry over A2A) and [[Strands Agents]] (multi-agent orchestration). ## Related - [[AI Agents]] - [[Agentic Engineering]] - [[Model Context Protocol (MCP)]] - [[Agentic Resource Discovery Specification (ARD)]] - [[MCP Gateway Registry]] - [[Strands Agents]] - [[Large Language Models (LLMs)]]