Verify an A2A agent card before trusting or routing to it: dual-probe /.well-known/agent-card.json and agent.json, check MUST fields (name/description/url/version/capabilities), classify protocolVersion, flag the known 0.3<->1.0 silent schema breaks, verify any JWS signature over RFC 8785 JCS canonical bytes (did:web key resolution), and live-probe the advertised interface with tasks/send. Per-step verdict + remediation.
| Network | Scheme | Amount | Pay To |
|---|---|---|---|
| Base | exact | $0.01 USDC | 0x8AfB...0Bc6 |