Your Agent Started Calling Other Agents. Who Verified Theirs?
A2A hit v1.0 this year and teams are wiring their agents to other teams' and vendors' agents. The moment your agent fetches an Agent Card and acts on it, you have extended your trust boundary to identity and code you do not control. The spec advertises auth schemes but leaves verification to you. Here is the admission gate that makes an outbound A2A call safe: verify the signed card, scope the credential you hand over, and block replays.