The Sequence Engineering #546: You Know MCP, but What About ACP
Another agentic protocol you should know about.
In recent months, the model context protocol(MCP) has evolved as one of the most interesting technologies in intelligence (AI). However, there is an interesting alternative pionered by top AI labs that is flying relatively under the radar.
The Agent Communication Protocol (ACP) addresses this challenge by enabling seamless interactions among autonomous AI agents. Building on the foundation laid by the Model Context Protocol (MCP), ACP supports more complex, multimodal, and persistent agent-to-agent communications. This essay explores ACP's architecture, its key components—including client-server interactions, agent discovery, lifecycle management, and message structures—and contrasts it with MCP to clarify their roles in the broader AI ecosystem.