This research presents an architecture that enables open, economically viable multi-agent ecosystems. Two core limitations of the Agent2Agent (A2A) protocol are addressed: decentralized agent discovery and integrated agent-to-agent micropayments. The current A2A protocol lacks discoverability, reputation, and integrated payment functionality, preventing agents from reliably finding, trusting, and compensating other agents. Agent-to-agent micropayments are essential as agents require compensation for their services, yet traditional payment methods prove unsuitable for micropayments due to onboarding requirements and overhead costs. To address these limitations, AgentCards are published on-chain as smart contracts, enabling tamper-evident, verifiable agent identities with decentralized discoverability. A2A is further extended through integration with the x402 open standard, which facilitates blockchain-agnostic, HTTP-based micropayments via HTTP 402 status code. This integration enables autonomous agents to seamlessly discover, authenticate, and compensate each other across organizational boundaries. A comprehensive prototype implementation demonstrates the feasibility of blockchain-based agent discoverability and seamless micropayment integration. Elements of this approach have subsequently been adopted in industry implementations and the development of Ethereum standards. The proposed approach establishes foundational infrastructure for secure, scalable, and economically viable multi-agent ecosystems, advancing agentic AI toward trusted autonomous economic interactions.