Agent-Agent interfaces and Google's new A2A protocol
This week, Google announced (↗) their new Agent-to-Agent protocol, A2A, designed to standardise how AI agents collaborate, even when run by different organisations using different underlying models. Positioned as complementary to MCP – which standardises agent access to external tools – A2A aims to standardise direct agent-agent communication. Google even declared A2A ♥️ MCP (↗), highlighting their vision for synergy between these protocols.
At Portia, we’ve been thinking about how agents interact with external systems via tools and agents for some time. You may have even read our post two weeks ago, Software interfaces in the agent era (↗). We divided the topic of agent integration with external systems into five categories based on increasing complexity, and A2A sits firmly at the top, in the Agent-Agent interface level.