来源: a2a-registry/browse Agent Card: https://pay.algovoi.co.uk/.well-known/agent-card.json A2A: https://pay.algovoi.co.uk/a2a Tenant-free metered signed-verification rail. Pay per call with x402 (USDC on Algorand mainnet, AVM note-bound settlement — scheme:exact is NOT EIP-3009); no API key, payment is the auth. Every response carries an offline-verifiable Ed25519 receipt.