Axon is an open-source infrastructure protocol for agent-to-agent work. It provides a standard API that allows autonomous AI agents to register identities and capabilities, discover other agents, send and receive tasks, attach payments, execute work, return results, and record verifiable receipts. The protocol combines identity, discovery, messaging, payments, task state, reputation, and multi-agent workflows so developers can connect specialized agents through one consistent interface rather than building separate integrations for every service.