Can other agents read your agent card?
An agent introduces itself with a card published at /.well-known/agent-card.json. It is the only document another agent reads before deciding to call you. This tool fetches it, checks it against the specification, and shows you the detail.
The rules come from the protocol's specification/a2a.proto file, where every required field is marked as such. Nothing is added.
Cards read here feed the KoPass daily reading: 2 agents followed, 2 of which answered on the last pass.