agenticweb.wiki

Agent Communication Protocol ACP · /agents

By Belgravia Labs Standards Observatory · Last verified · 5 primary sources

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.

Coordinate 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 [1][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 [1].

Overview

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 [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 [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already covered by a2a, and because the issuer itself declares the protocol subsumed, this record's phase is set to "withdrawn" and its implementation to "deprecated" per Ruling 11 — it is kept as a historical record rather than deleted, since some deployments and SDKs (acp-sdk on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 [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.

Discovery and probe

GET /agents (Agent Discovery endpoint) · /agents

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

Not probed live: superseded. IBM ACP was archived and merged into A2A; /agents is not expected on new deployments.

Instances

Every instance with its source is listed on the instances page.

Verified SDKs, reference implementations & validators:

See also

Comparisons

References

  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 (2026-09-05) VERIFIED
  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 (2026-09-05) VERIFIED
  3. IBM's Agent Communication Protocol is deprecated (merged into A2A) — https://github.com/i-am-bee/acp (2026-10-16) VERIFIED
  4. v1.0.3 released 2025-08-21 — https://github.com/i-am-bee/acp/releases/tag/v1.0.3 (2025-08-21) VERIFIED
  5. No push since 2025-08-25 (over 180 days) — https://github.com/i-am-bee/acp/releases/tag/v1.0.3 (2025-08-21) REPORTED

Verification log and errata

JSON · Markdown · OKF v0.2

Frequently asked questions

What is Agent Communication Protocol (ACP)?
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.
What is the adoption and standardization status of Agent Communication Protocol?
"ACP is now part of A2A under the Linux Foundation" (repository banner), formerly IBM BeeAI; archived, functionality merged into A2A under the Linux Foundation. Implementation: none found. Version: v1.0.3 (2025-08-21). Last verified 2026-10-23.
How does Agent Communication Protocol compare to other coordinate protocols?
Agent Communication Protocol (ACP) is one of 13 standards at step 6, Coordinate (Talk to another agent). It pairs with Agent2Agent Protocol (A2A), Model Context Protocol, Open Agentic Schema Framework. Head-to-head comparisons on this site: Agent Client Protocol, Agent2Agent Protocol (A2A), Agent Connect Protocol. Every standard at this step is listed at https://agenticweb.wiki/category/coordinate/.