Agent Communication Protocol (ACP)

The Agent Communication Protocol was an open standard for messaging between AI agents, applications, and humans, originally developed by IBM Research as part of the BeeAI project. Where A2A focused on the agent-to-agent peer protocol over JSON-RPC, ACP took a REST/OpenAPI approach with framework-agnostic wrappers around BeeAI, LangChain, CrewAI, and custom agents. ACP and A2A overlapped enough that the Linux Foundation merged them in August 2025: the i-am-bee/acp GitHub repository was archived, and the official ACP documentation now states that ACP is part of A2A. New work should target A2A directly.

You may still encounter ACP in two places. First, in older blog posts and tutorials from spring 2025 that pre-date the merge. Second, in the BeeAI codebase, which kept its agent framework after donating its protocol to A2A. If you read about ACP today, treat it as historical context. The pattern, framework-agnostic agent messaging, lives on inside A2A. The Linux Foundation move consolidates the ecosystem around one standard rather than fragmenting it across vendor protocols.

You should not start new ACP integrations. The protocol is in maintenance mode and the official guidance is to use A2A. Knowing the term is still useful for reading older content and understanding why some BeeAI examples reference ACP-style endpoints.

• ACP official docs (now part of A2A)
• ACP repo (archived August 2025)
• A2A docs (successor)

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