--- type: Agentic Web Standard title: "Agent Communication Protocol" description: "How did agents, applications, and people exchange multimodal REST messages before merging into A2A?" resource: "https://github.com/i-am-bee/acp" tags: ["coordinate", "endpoint", "linux-foundation", "agent-to-agent-messaging", "describe-agent-capabilities"] status: deprecated generated: { by: agenticweb-builder/1.0, at: 2026-10-30T00:00:00Z } verified: { by: process:agenticweb-engine, at: 2026-10-23T00:00:00Z } stale_after: 2026-11-22T00:00:00Z sources: - id: ref-1 resource: "https://github.com/i-am-bee/acp" title: "The i-am-bee/acp GitHub repository was archived by the owner on 2025-08-27 and is read-only; its README banner states \"ACP is now part of A2A under the Linux Foundation!\" with a link to a migration guide." last_modified: 2026-09-05T00:00:00Z - id: ref-2 resource: "https://raw.githubusercontent.com/i-am-bee/acp/main/docs/spec/openapi.yaml" title: "The ACP OpenAPI specification (v0.2.0) defines GET /agents for agent discovery, GET /ping for liveness, and a /runs resource for stateless/stateful/streamed execution." last_modified: 2026-09-05T00:00:00Z - id: ref-3 resource: "https://github.com/i-am-bee/acp" title: "IBM's Agent Communication Protocol is deprecated (merged into A2A)" last_modified: 2026-10-16T00:00:00Z - id: ref-4 resource: "https://github.com/i-am-bee/acp/releases/tag/v1.0.3" title: "v1.0.3 released 2025-08-21" last_modified: 2025-08-21T00:00:00Z - id: ref-5 resource: "https://github.com/i-am-bee/acp/releases/tag/v1.0.3" title: "No push since 2025-08-25 (over 180 days)" last_modified: 2025-08-21T00:00:00Z --- # Agent Communication Protocol Agent Communication Protocol (ACP) is an agentic-web standard (endpoint — /agents) at step 6, Coordinate, formerly IBM BeeAI; its status is "ACP is now part of A2A under the Linux Foundation". It answers: "How did agents, applications, and people exchange multimodal REST messages before merging into A2A?" Implementation status is none found, last verified 2026-10-23. # Overview IBM's Agent Communication Protocol (ACP) was an open REST protocol, built by IBM's BeeAI project, for exchanging multimodal messages (text, code, files, media) between agents, applications, and people, with support for synchronous, background, and streamed responses and for stateless or stateful execution [^ref-1][^ref-2]. It solved the same problem A2A now solves: letting agents built on different frameworks discover each other's capabilities (`GET /agents`) and run tasks (`POST /runs`) over a standard REST/OpenAPI surface, and it powered agent discovery and execution on IBM's BeeAI Platform [^ref-1]. ACP does not exist as an independent, live protocol any more. Its GitHub repository (`i-am-bee/acp`) was archived by its owner on 2025-08-27 and is now read-only [^ref-1]; the repository's README carries a banner stating "ACP is now part of A2A under the Linux Foundation!" and links a migration guide directing implementers to Google/Linux Foundation's A2A protocol instead [^ref-1]. Because the record here would otherwise duplicate a step already covered by `a2a`, and because the issuer itself declares the protocol subsumed, this record's phase is set to "withdrawn" and its implementation to "deprecated" per Ruling 11 — it is kept as a historical record rather than deleted, since some deployments and SDKs (`acp-sdk` on PyPI/npm) may still exist in the wild. At time of archival the final repository release was v1.0.3 (2025-08-21) and the last published OpenAPI spec file was v0.2.0, exposing `GET /ping` (liveness), `GET /agents` (agent discovery, paginated via `limit`/`offset`), and a `/runs` family of endpoints for execution [^ref-2]. Governance had been IBM BeeAI-led community governance; there is no evidence ACP itself was ever formally adopted by a Linux Foundation working group before being merged — rather, its functionality and some contributors moved into the A2A project, which is the Linux Foundation-governed successor. What is unresolved: whether any production deployments continue to run the archived ACP server surface independently of A2A; no such deployment was found. # Examples ```http GET {origin}/agents # parse: JSON array of agent objects would confirm a live ACP server; in practice the repository is archived and this is not expected to resolve on new deployments # on absent: Expected: the protocol was retired in August 2025 and superseded by A2A, so absence is the normal case ``` # Knowledge Graph * **Lifecycle Step**: [6 Coordinate](/category/coordinate/index.md) * **Pairs with**: [Agent2Agent Protocol (A2A)](/okf/protocols/a2a.md), [Model Context Protocol](/okf/protocols/mcp.md), [Open Agentic Schema Framework](/okf/protocols/oasf.md), [Agent Protocol](/okf/protocols/agent-protocol-aief.md), [Natural Language Interaction Protocol (NLIP)](/okf/protocols/nlip.md), [Agent Transfer Protocol](/okf/protocols/agtp.md) * **Related terms**: [ACP (four protocols)](/okf/terms/acp.md) * **Compared in**: [Agent Client Protocol vs Agent Communication Protocol](/compare/agent-client-protocol-vs-agent-communication-protocol/index.md), [Agent2Agent Protocol (A2A) vs Agent Communication Protocol](/compare/a2a-vs-agent-communication-protocol/index.md), [Agent Communication Protocol vs Agent Connect Protocol](/compare/agent-communication-protocol-vs-agent-connect-protocol/index.md), [Agent Communication Protocol vs Agentic Commerce Protocol](/compare/agent-communication-protocol-vs-agentic-commerce-protocol/index.md) [^ref-1]: The i-am-bee/acp GitHub repository was archived by the owner on 2025-08-27 and is read-only; its README banner states "ACP is now part of A2A under the Linux Foundation!" with a link to a migration guide. (https://github.com/i-am-bee/acp) [^ref-2]: The ACP OpenAPI specification (v0.2.0) defines GET /agents for agent discovery, GET /ping for liveness, and a /runs resource for stateless/stateful/streamed execution. (https://raw.githubusercontent.com/i-am-bee/acp/main/docs/spec/openapi.yaml) [^ref-3]: IBM's Agent Communication Protocol is deprecated (merged into A2A) (https://github.com/i-am-bee/acp) [^ref-4]: v1.0.3 released 2025-08-21 (https://github.com/i-am-bee/acp/releases/tag/v1.0.3) [^ref-5]: No push since 2025-08-25 (over 180 days) (https://github.com/i-am-bee/acp/releases/tag/v1.0.3)