A2A Protocol
A2Aプロトコル
Definition
An A2A protocol is a communication approach that lets AI agents exchange tasks, status, and results. It matters when AI systems move from single-agent workflows to coordinated multi-agent systems.
As AI systems become more capable, some products split work across multiple agents: one gathers information, another writes code, another reviews the result, and another performs an action. An A2A protocol, short for agent-to-agent protocol, is a way for agents to communicate tasks, status, results, and requests for help.
Why it matters
Multi-agent systems can be useful when different agents have different tools, permissions, or specialties. But coordination becomes fragile if each agent sends unstructured messages that others cannot interpret reliably. A2A protocols aim to make handoffs more explicit by describing tasks, capabilities, intermediate results, failures, and completion states in a consistent format.
How to read AI news about it
When a product mentions A2A, check what is actually standardized. Is it only a message format, or does it include task delegation, capability discovery, authentication, permissions, and audit logs? Also ask whether it is meant for interoperability across vendors or only for coordination inside one platform. Those distinctions determine how important the announcement is.
Common uses
A research agent might collect sources, a writing agent might draft a report, a review agent might check facts, and an execution agent might update a system. In software engineering, separate implementation and review agents can make the workflow easier to inspect. In business operations, specialized agents can work on parts of a process while a coordinator agent manages state.
Watch-outs
More agents do not automatically mean better results. Multi-agent systems can add latency, cost, duplicated work, unclear responsibility, and cascading errors. The practical question is whether the protocol makes coordination safer and easier to debug. A2A is best understood as infrastructure for complex agent workflows, not as proof that the workflow will be reliable by itself.