IBM ACP (Agent Communication Protocol) / BeeAI

A REST-based protocol for lightweight agent invocation. Launched by IBM Research in March 2025 under the Linux Foundation's BeeAI community. Now officially part of A2A under the Linux Foundation.

Layers addressed

• Discovery — Capability descriptions declared at build time (offline discovery)
• Messaging — RESTful API calls between agents

How it works

Simple REST-based invocation. Agents are packaged with capability descriptions at build time — no runtime discovery dependency. Uses MIME-type-based message structure rather than predefined formats. Supports agents ranging from small stateless serverless functions to long-running conversational agents.

The key design choice: offline discovery. Agent capabilities are declared when the agent is built, not negotiated at runtime. This makes it simpler than A2A's dynamic Agent Cards but less flexible.

What it leaves to other layers

• Identity. Limited authentication story of its own.
• Coordination. No persistent relationships or state between invocations.
• Streaming. REST-based design is not well suited for real-time streaming or high-frequency interactions.

Status

Now officially part of A2A under the Linux Foundation. The BeeAI community (i-am-bee on GitHub) remains active as the reference implementation, and ACP remains framework-agnostic with Python and TypeScript SDKs.

Links

• agentcommunicationprotocol.dev