a2a Google Agentic Interoperability Protocol · MCP Model Context Protocol by Anthropic
Agent interoperability is the latest buzz in town. First, it was MCP (Model Context Protocol) from Anthropic, and now, with the latest announcement (April 9) of Google’s A2A (Agent2Agent) protocol, it seems there’s a growing push toward establishing interoperability standards.
But why?
The concept of agent interoperability definitely holds promise. Agreeing upon a standard data exchange format between different products and platforms — each exposing their capabilities as agents — would allow seamless integration into each other’s ecosystems and enable open communication.
However, at present, the protocol feels more like a wrapper around existing internet communication standards, adding a layer of abstraction and reclassifying older capabilities.
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Both A2A and MCP propose a client-server architecture. A2A claims to complement the MCP protocol. While MCP focuses on resources and tools, A2A is targeted at agents — without the need to share tools, resources, or memory. I believe today’s agentic applications are already designed using this model. However, you can compare current designs to thick client applications, where the client handles much of the logic for processing server responses. In contrast, A2A and MCP aim for thin client applications, where the server-side agent is responsible for completing tasks.
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The communication protocol is built on HTTP, JSON-RPC, and SSE (for streaming), with authentication happening out-of-band. This implies that the API key will not be included in the agent payload.
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Capability discovery via an “Agent Card” works much like API discoverability — publishing agent capabilities for public or internal access, similar to API registries or Swagger. This could be a major enabler for agent interoperability. But if the Agent Card is just a JSON-based spec, why not leverage existing tools like Swagger or API registries to host it? Doing so could accelerate ecosystem growth by reducing client-side processing and standardizing responses server-side.
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Task Management. Agents will be designed to accomplish goals through collaboration — engaging with other agents, performing handshakes, conducting synchronous and asynchronous status checks, and communicating responses (called “Artifacts”) back to the client agent. A key distinction here is that, in current designs, once a response is received, the responsibility of validation and corrective action lies with the client agent. In the new architecture, however, the server-side agent will take on the responsibility of task completion and generating alternate responses if needed.
This is a promising start. The industry has begun to seriously consider agent interoperability, though it’s worth noting that — even after decades of efforts around application-level protocols, healthcare interoperability (FHIR/HL7), and data interoperability (Apache Iceberg) — we’re still far from achieving seamless integration in the existing IT landscape. A2A and MCP will require significant maturity and broader industry adoption to truly take off.
📖 For a detailed read, refer to Google’s documentation: Home 📰 For an easier overview, check out Google’s blog post: Announcing the Agent2Agent Protocol (A2A) — Google Developers Blog