Protocol
Agent Communication Protocol (ACP)
Definition
A protocol for structured communication between agents and external systems, focusing on standardized message formats, capability negotiation, and session management. ACP defines how agents declare what they can do, how they exchange requests and responses, and how they handle errors and timeouts in multi-turn interactions.
Builder Context
ACP is emerging alongside MCP and A2A as part of the agent interoperability stack. When evaluating protocols, consider: MCP for tool integration (synchronous, model-to-tool), A2A for agent-to-agent delegation (asynchronous, agent-to-agent), and ACP for structured communication patterns. Most production systems will use a combination.