
What Is Agent-to-Agent (A2A)? The New AI Attack Surface — and How to Govern It
For two years the story of enterprise AI has been an agent calling a model, and — more recently — an agent calling a tool. There's a third call now, and most teams can't see it: an agent calling another agent. That hop has a name — agent-to-agent (A2A) — and it is the least-governed surface in the entire AI stack.
This post is a practical definition of A2A: what the protocol actually is, why the delegation hop between two agents is a blind spot your existing controls don't cover, and what it takes to govern it.








