ERC-8004 Agent Liveness

Gold402 Verified. Hand-reviewed and on the curated list — curation is the bar. The stamp means a human read this entry and the endpoint answered when we knocked. It is not a delivery test: we have not paid this service and graded what came back, so treat it as "reachable and speaks the protocol," never as "this is worth the money."

Checks whether an agent registered in the real ERC-8004 Identity Registry (Base Sepolia testnet) is actually alive right now: resolves its on-chain registration file and runs a real MCP `initialize` handshake against the declared endpoint. $0.10 USDC on Base Sepolia (testnet) via x402. Example: `POST /verify-registered-agent {"agent_id":1}`. ([OpenAPI](https://erc8004-agent-liveness-325572559480.us-central1.run.app/openapi.json)) ([Agent Card](https://erc8004-agent-liveness-325572559480.us-central1.run.app/.well-known/agent-card.json)) ([GitHub](https://github.com/nexus-mcp-infra/erc8004-agent-liveness))