What is the A2A (Agent-To-Agent) Protocol? Link to heading

In short, A2A is a protocol that enables communication between autonomous agents in a decentralized and secure way. It can be used to delegate tasks, exchange information, or facilitate collaboration between systems powered by large language models (LLMs).

To better understand this, let’s first consider how things work in the human world. In society, each person has their role, a unique set of skills and knowledge that makes them more suited to perform certain tasks than others. When we receive a task, we start by analyzing it, take responsibility for it, and try to achieve a specific outcome. If there’s a part we can’t handle ourselves, we may look for someone who can help — and once we find that person, we delegate that part of the task to them.

In the context of the A2A protocol, an agent is like that person — a specialized entity with specific capabilities. Technically speaking, an agent is an application exposing a set of endpoints.

How Do Agents Discover Each Other? Link to heading

Good question!

Agent Card: A Metadata Profile Link to heading

Discovery starts with something called an Agent Card. This is a lightweight JSON metadata file that describes:

  • The agent’s capabilities
  • Communication endpoints
  • Identity and trust settings

Standard location:
domain.com/.well-known/agent.json

This ensures the Agent Card is easy to find, just like robots.txt in SEO or .well-known in SSL certificates.

Catalogs and Agent Directories Link to heading

While Agent Cards help expose agent details, they must also be registered in a cataloging system — a decentralized directory or registry. This allows:

  • Agent search and lookup
  • Discovery based on functionality
  • Dynamic ecosystem growth

What’s Next for the A2A Protocol? Link to heading

We’re moving from the “app for everything” era to the “agent for everything” era. With protocols like A2A and support systems like MCP (Model Context Protocol), expect:

  • AI marketplaces for agents
  • Tools that orchestrate agent collaboration
  • Decentralized applications powered by multi-agent systems

The future is interoperable AI - where intelligent agents work together to build smarter ecosystems.