Agent-to-Agent Protocol (A2A)

What is the Agent-to-Agent Protocol?

Previously, a marketing agent from vendor A couldn’t work with an analytics agent from vendor B without building proprietary interfaces. A2A solves exactly this problem and significantly reduces integration costs for multi-agent systems. The protocol uses proven web technologies like HTTP and JSON-RPC and prevents vendor lock-in — a decisive factor for companies planning their AI strategy long-term.

The Agent-to-Agent Protocol (A2A) is an open standard developed by Google that allows AI agents from different vendors to communicate directly with each other. The protocol defines how agents discover each other (via Agent Cards), exchange tasks, report progress, and return results. It complements the Model Context Protocol (MCP), which primarily governs communication between LLMs and tools.

A2A is based on familiar web technologies like HTTP and JSON-RPC and defines several core concepts: Tasks (tasks with lifecycle), Artifacts (results), Messages (messages between agents), and Parts (various content types like text or files). An agent can act as a client sending a task to another agent that acts as a server. The protocol supports both synchronous and asynchronous communication — important for long-running tasks.

For companies, A2A means they can connect AI agents from different vendors in an Agentic Mesh without developing proprietary interfaces. A marketing agent from vendor A can work directly with an analytics agent from vendor B. This reduces integration costs and prevents vendor lock-in — a decisive factor for scalable AI strategies.