Most "AI integration" still means a human reads your docs and writes a client. A2A flips that: another agent reads a small machine description of what your service does and calls it directly — no browser, no scraping, no human in the loop. I wired it up on a small tool I run (a free llms.txt validator) and it's simpler than the acronyms suggest. Here's the whole thing, with the real requests.
What A2A actually is
A2A (Agent2Agent) is an open protocol — now under the Linux Foundation — that lets AI agents discover and call each other over plain HTTP. Think of it as the agent-to-agent counterpart of a public API: instead of publishing OpenAPI docs for humans, you publish a machine description another agent can consume and invoke.
It has exactly two moving parts:
The agent card — a discovery document.
