What Is the A2A Protocol? Agent Cards and Tasks Explained

The A2A Protocol, short for Agent2Agent Protocol, is an open standard for communication between independent AI agent systems.

That sentence sounds simple, but it implies something most AI agent demos skip entirely. Most demos still assume one assistant, one runtime, one tool loop, and one owner — the agent can search, call tools, write code, query APIs, maybe use MCP servers, and return an answer.

A2A is designed for a different world, one where agents may be built by different teams, frameworks, vendors, languages, or organizations. It assumes one agent may need to discover another agent, understand what it can do, send it work, exchange messages, receive files or structured outputs, and track a task until completion — making it not just another tool calling format, but a genuine attempt to make AI agents interoperable as peers.

The core concepts are:

Agent Cards