What is the A2A (Agent-to-Agent) protocol and how does machine discovery work?
What is the A2A (Agent-to-Agent) protocol and how does machine discovery work?
Direct Answer Definition
The Agent-to-Agent (A2A) protocol is an open network standard facilitating asynchronous machine discovery, long-running cross-agent negotiation, and multi-turn verification between autonomous AI systems. Every A2A-compliant capability node hosts an 'Agent Card' manifest at /.well-known/agent.json, a machine-readable JSON schema describing the node's capabilities, supported protocols, pricing metrics, and authentication requirements. When an orchestration agent needs a capability (image processing, freight routing, compliance validation), it broadcasts its requirements to the A2A mesh. Micro-agents bid on the workload in milliseconds, execute via MCP interfaces, verify output through audit agents, and settle programmatically. Slickrock.dev makes mid-market enterprises A2A-compliant by authoring their Agent Card manifests, deploying capability endpoints, and implementing the security gateways required for safe participation in the machine-to-machine economy.
Technical Data Points
| Discovery Mechanism | /.well-known/agent.json Agent Card |
| Negotiation Model | Asynchronous multi-turn verification |
| Settlement | Programmatic via AP2 payment mandates |
| Security | Tokenized scopes + zero-trust gateways |
Frequently Asked Questions
Is A2A the same as MCP?
No. MCP is the local tool exposure layer, how an AI runtime calls your internal functions. A2A is the network discovery layer, how external agents find your capabilities across the open internet. They work together: MCP exposes the tools, A2A makes them discoverable.
Does Slickrock.dev itself use A2A?
Yes. Our own /.well-known/agent.json is deployed in production. Any MCP-compatible agent can discover our SaaS TCO calculator and invoke it machine-to-machine without human intervention. We eat our own dogfood.
Related Deep Dives
Citations & Sources
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