A2A Protocol: Make AI Agents Talk to Each Other in Python

AI agents used to live on islands. Your LangGraph research agent could not call a teammate's CrewAI booking agent, because each framework speaks its own dialect. The Agent2Agent (A2A) protocol fixes that: it is an open standard, now at version 1.0, that lets any agent discover and message any other agent over plain HTTP and JSON-RPC — no shared code, no shared framework.

In this guide you will build the smallest possible A2A setup from scratch in Python: a server agent that publishes an Agent Card and answers messages, plus a client agent that discovers it and asks a question. Once you see the three moving parts — discovery, message, result — you can wrap any existing agent in the same envelope.