agenticweb.wiki

Agent Connect Protocol

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This page is about the Agent Connect Protocol (ACP), the REST interface for invoking remote agents that the AGNTCY project (started by Outshift by Cisco) published in 2025 and has since deprecated in favour of the Agent2Agent Protocol (A2A). It is not IBM's Agent Communication Protocol (ACP), which merged into A2A in August 2025. It is not the Agent Client Protocol (ACP) that Zed created for coding agents in editors. And it is not the Agentic Commerce Protocol (ACP) from OpenAI and Stripe. All four are listed under ACP.

Overview

The Agent Connect Protocol was AGNTCY's answer to a narrow question: how a client or another agent can call an agent that runs somewhere else and was built with a different framework, over ordinary HTTP [5][10]. It covered finding agents on a server, reading each agent's descriptor, and starting runs, either one-off or within a thread that keeps state between calls, with results returned by waiting, polling or streaming [10]. AGNTCY shipped a Python SDK and an Agent Workflow Server that exposed LangGraph and LlamaIndex agents through ACP [33][34][36]. In August 2025 AGNTCY's maintainers said they were deprecating ACP in favour of A2A [21]; the documentation was then marked inactive and removed [18][22][24][26], OASF marked its ACP objects deprecated [8][23][29], and the repositories were archived in April 2026 [9][27][28].

What it specified

Deprecation timeline

Not to be confused with

Who uses it

Who reads it

Who still supports or handles ACP

Recent coverage

See also

References

  1. Linux Foundation press release, Linux Foundation Welcomes the AGNTCY Project to Standardize Open Multi-Agent System Infrastructure and Break Down AI Agent Silos, 2025-07-29, checked 2026-10-29: "Initially open sourced by Cisco in March 2025, with collaboration from LangChain and Galileo" "SAN FRANCISCO, July 29, 2025 – The Linux Foundation, the nonprofit organization enabling mass innovation through open source, today welcomed the AGNTCY project, an open source infrastructure that enables discovery, identity, messaging, and observability among AI agents from different vendors and frameworks." "Cisco, Dell Technologies, Google Cloud, Oracle, and Red Hat have joined as formative members of the AGNTCY project under Linux Foundation governance." — https://www.linuxfoundation.org/press/linux-foundation-welcomes-the-agntcy-project-to-standardize-open-multi-agent-system-infrastructure-and-break-down-ai-agent-silos
  2. Galileo blog (Yash Sheth and Conor Bronsdon), AGNTCY: Building the Future of Multi-Agentic Systems, 2025-03-05, checked 2026-10-29: "Galileo, Langchain, and Cisco have come together to begin building towards a truly Multi-Agentic future, with Glean and LlamaIndex joining as supporting members." "Mar 5, 2025 AGNTCY: Building the Future of Multi-Agentic Systems" "Agent Connect Protocol (ACP) & SDK Enables standardized communication between agents across frameworks Handles message passing, state management, and context sharing Specification available now at https://github.com/agntcy/acp-spec" — https://galileo.ai/blog/agntcy-open-collective-multi-agent-standardization
  3. Outshift by Cisco, AGNTCY | Internet of Agents, checked 2026-10-29: "AGNTCY was created by Outshift and is now a Linux Foundation project." "Launch date: March 6, 2025" — https://outshift.cisco.com/the-internet-of-agents/agntcy
  4. GitHub REST API, repository agntcy/acp-spec, checked 2026-10-29: ""full_name":"agntcy/acp-spec"" ""created_at":"2025-02-05T02:13:00Z"" ""archived":true" ""spdx_id":"Apache-2.0"" — https://api.github.com/repos/agntcy/acp-spec
  5. agntcy/acp-spec, Agent Connect Protocol Specification (README.md), checked 2026-10-29: "This repo contains the specification of Agent Connect Protocol (ACP) proposed by the Agntcy Collective." "The Agent Connect Protocol defines a standard interface to invoke and configure remote agents over an API. The protocol is specified in OpenAPI a REST-based schema specification." "Distributed under Apache 2.0 License." "Copyright AGNTCY Contributors" — https://raw.githubusercontent.com/agntcy/acp-spec/main/README.md
  6. agntcy/governance, working-groups/core/CHARTER.md, AGNTCY Core Working Group Charter, checked 2026-10-29: "Open Agentic Schema Framework (OASF) - Agent Connect Protocol (ACP)" — https://raw.githubusercontent.com/agntcy/governance/main/working-groups/core/CHARTER.md
  7. GitHub REST API, commit history of agntcy/governance working-groups/core/CHARTER.md, checked 2026-10-29: ""date":"2026-05-28T02:31:40Z"" — https://api.github.com/repos/agntcy/governance/commits?path=working-groups/core/CHARTER.md
  8. Open Agentic Schema Framework schema server (schema.oasf.outshift.com), Modules, schema 1.1.0, checked 2026-10-29: "acp ACP Manifest [201] 201 Agent Connect Protocol manifest DEPRECATED since v0.8.0 ACP is deprecated, please use A2A instead." — https://schema.oasf.outshift.com/1.1.0/modules
  9. GitHub, repository agntcy/acp-spec, Agent Connect Protocol Specification (archive notice), checked 2026-10-29: "This repository was archived by the owner on Apr 11, 2026. It is now read-only." — https://github.com/agntcy/acp-spec
  10. agntcy/acp-spec, openapi.json, Agent Connect Protocol (OpenAPI 3.1.1, version 0.2.3), checked 2026-10-29: ""openapi": "3.1.1"" ""title": "Agent Connect Protocol"" ""version": "0.2.3"" "Details of the ACP features and the schemas are kept in the ACP descriptor of the specific agent. This object can be retrieved through this ACP interface or is found in the ACP extension of the agent record in the agent directory." ""name": "Threads"" ""name": "Thread Runs"" ""name": "Stateless Runs"" ""/agents/search"" ""/agents/{agent_id}/descriptor"" — https://raw.githubusercontent.com/agntcy/acp-spec/main/openapi.json
  11. GitHub REST API, releases of agntcy/acp-spec (0 releases), checked 2026-10-29: "[]" — https://api.github.com/repos/agntcy/acp-spec/releases?per_page=20
  12. GitHub REST API, tags of agntcy/acp-spec (0 tags), checked 2026-10-29: "[]" — https://api.github.com/repos/agntcy/acp-spec/tags?per_page=30
  13. GitHub REST API, commits of agntcy/acp-spec, checked 2026-10-29: ""date":"2025-05-23T13:53:59Z"" "feat: Adding basic type support for input, output and config (#46)" — https://api.github.com/repos/agntcy/acp-spec/commits?per_page=10
  14. PyPI JSON API, agntcy-acp, checked 2026-10-29: ""version":"1.5.2"" ""upload_time":"2025-06-16T13:21:17"" — https://pypi.org/pypi/agntcy-acp/json
  15. GitHub REST API, releases of agntcy/acp-sdk, checked 2026-10-29: ""tag_name":"v1.5.2"" ""published_at":"2025-06-16T13:20:38Z"" — https://api.github.com/repos/agntcy/acp-sdk/releases?per_page=20
  16. spec.acp.agntcy.org, Agent Connect Protocol (hosted OpenAPI viewer), checked 2026-10-29: "Agent Connect Protocol" — https://spec.acp.agntcy.org/
  17. spec.acp.agntcy.org, openapi.json (hosted copy), checked 2026-10-29: ""openapi": "3.1.1"" ""title": "Agent Connect Protocol"" ""version": "0.2.3"" — https://spec.acp.agntcy.org/openapi.json
  18. agntcy/docs, docs/syntactic/connect.md, Agent Connect Protocol, at commit a23e3c7 (last state before removal in PR #270), checked 2026-10-29: "This component is not currently under active development. While it remains available, updates and new features are not planned at this time." "We propose a solution where all agents are able to communicate over the network using a standard protocol to interoperate. We call it the Agent Connect Protocol (ACP)." — https://raw.githubusercontent.com/agntcy/docs/a23e3c757391e13b9834a59b26a0a33d8d70a328/docs/syntactic/connect.md
  19. agntcy/docs, docs/manifest/manifest.md, Agent Manifest, at commit a23e3c7 (before removal), checked 2026-10-29: "The manifest is designed to be used by Agent Connect Protocol and the Agent Workflow Server and stored in the Agent Directory with the corresponding OASF extensions." — https://raw.githubusercontent.com/agntcy/docs/a23e3c757391e13b9834a59b26a0a33d8d70a328/docs/manifest/manifest.md
  20. agntcy/acp-spec, docs/sample_acp_descriptors/mailcomposer.json, checked 2026-10-29: ""name": "org.agntcy.mailcomposer"" — https://raw.githubusercontent.com/agntcy/acp-spec/main/docs/sample_acp_descriptors/mailcomposer.json
  21. GitHub, agntcy/governance issue #30, Update AGP reference in the Core WG charter to SLIM (comment by muscariello, 2025-08-21), checked 2026-10-29: "Core WG needs to be updated also because we are deprecating ACP in favor of A2A. I will propose an update and ask TSC approval for that." — https://github.com/agntcy/governance/issues/30
  22. GitHub, agntcy/docs PR #191, chore: adding notice to components that are not currently worked on, checked 2026-10-29: "Added notice that the following components are not being actively developed: ACP Workflow Server Workflow Server Manager Agent Manifest" — https://github.com/agntcy/docs/pull/191
  23. GitHub REST API, releases of agntcy/oasf, checked 2026-10-29: ""tag_name":"v0.8.0"" ""published_at":"2025-10-22T13:22:51Z"" — https://api.github.com/repos/agntcy/oasf/releases?per_page=40
  24. GitHub, agntcy/docs PR #270, Remove deprecated components, checked 2026-10-29: "Fixes #170 Removing documentation on deprecated components." — https://github.com/agntcy/docs/pull/270
  25. GitHub REST API, files changed in agntcy/docs pull request #270, checked 2026-10-29: ""filename":"docs/syntactic/connect.md"" ""status":"removed"" — https://api.github.com/repos/agntcy/docs/pulls/270/files?per_page=100
  26. GitHub, agntcy/docs PR #335, chore: removing ACP and fixing links, checked 2026-10-29: "This PR removes the last few mentions of ACP from the documentation and updates a link." — https://github.com/agntcy/docs/pull/335
  27. GitHub, repository agntcy/acp-sdk, Agent Connect Protocol SDK (archive notice), checked 2026-10-29: "This repository was archived by the owner on Apr 11, 2026. It is now read-only." — https://github.com/agntcy/acp-sdk
  28. GitHub, repository agntcy/workflow-srv, Agent Workflow Server (archive notice), checked 2026-10-29: "This repository was archived by the owner on Apr 11, 2026. It is now read-only." — https://github.com/agntcy/workflow-srv
  29. GitHub, agntcy/oasf, Release v1.1.0, 2026-07-10, checked 2026-10-29: "Deprecated ACP objects – Deprecated ACP-related objects and dictionary entries in the schema and server (#445)" — https://github.com/agntcy/oasf/releases/tag/v1.1.0
  30. LF AI & Data community blog (Kate Blair, IBM Research, and Todd Segal, Google), ACP Joins Forces with A2A, 2025-08-29, checked 2026-10-29: "IBM Research launched the Agent Communication Protocol (ACP) in March 2025 to power its BeeAI Platform" "Today, we're excited to share that ACP is officially merging with the A2A under the Linux Foundation (@thelinuxfoundation) umbrella." — https://lfaidata.foundation/communityblog/2025/08/29/acp-joins-forces-with-a2a-under-the-linux-foundations-lf-ai-data/
  31. Zed blog (Nathan Sobo), Bring Your Own Agent to Zed — Featuring Gemini CLI, 2025-08-27, checked 2026-10-29: "we created the Agent Client Protocol (ACP), and we've partnered with Google to integrate Gemini CLI as the initial reference implementation." — https://zed.dev/blog/bring-your-own-agent-to-zed
  32. Stripe blog (Jeff Weinstein and Steve Kaliski), Developing an open standard for agentic commerce, 2025-09-29, checked 2026-10-29: "powered by the Agentic Commerce Protocol (ACP), a new open standard codeveloped by Stripe and OpenAI that enables programmatic commerce flows between buyers, AI agents, and businesses." — https://stripe.com/blog/developing-an-open-standard-for-agentic-commerce
  33. agntcy/workflow-srv, README.md, Agent Workflow Server, checked 2026-10-29: "The Agent Workflow Server (AgWS) enables participation in the Internet of Agents (IoA). It accommodates AI Agents from diverse frameworks and exposes them through Agent Connect Protocol (ACP), regardless of their underlying implementation." — https://raw.githubusercontent.com/agntcy/workflow-srv/main/README.md
  34. agntcy/docs, docs/agws/workflow-server.md, Agent Workflow Server, at commit a23e3c7 (before removal), checked 2026-10-29: "| LangGraph | >=0.2.60,<0.4.0 | ✔️ | 🚧 | 🚧 | 🚧 | ✔️ | | LlamaIndex | >=0.12.0,<0.13.0" — https://raw.githubusercontent.com/agntcy/docs/a23e3c757391e13b9834a59b26a0a33d8d70a328/docs/agws/workflow-server.md
  35. GitHub REST API, repository agntcy/workflow-srv, checked 2026-10-29: ""pushed_at":"2025-09-15T00:18:23Z"" ""archived":true" — https://api.github.com/repos/agntcy/workflow-srv
  36. agntcy/docs, docs/syntactic/agntcy_acp_sdk.md, Agntcy ACP Client, at commit a23e3c7 (before removal), checked 2026-10-29: "The SDK is current available in Python" "The SDK provides integration with LangGraph with the {py:obj}agntcy_acp.langgraph.ACPNode class that can be used as a graph node" — https://raw.githubusercontent.com/agntcy/docs/a23e3c757391e13b9834a59b26a0a33d8d70a328/docs/syntactic/agntcy_acp_sdk.md
  37. GitHub REST API, repository agntcy/acp-sdk, checked 2026-10-29: ""pushed_at":"2025-06-16T13:20:38Z"" ""archived":true" — https://api.github.com/repos/agntcy/acp-sdk
  38. agntcy/docs, docs/how-to-guides/mas-creation-tutorial/mas-tutorial.md, Getting Started: Build Your First Multi-Agent Software, at commit a23e3c7 (before removal), checked 2026-10-29: "This tutorial guides you through the process of building a distributed multi-agent application using LangGraph and leveraging Agent Connect Protocol (ACP) and other AGNTCY components and tools." "This agent is written using LangGraph, it provides an Agent Manifest which allows to deploy it through the Agent Workflow Server and be consumed through ACP." — https://raw.githubusercontent.com/agntcy/docs/a23e3c757391e13b9834a59b26a0a33d8d70a328/docs/how-to-guides/mas-creation-tutorial/mas-tutorial.md
  39. a2aproject/A2A, GOVERNANCE.md, Agent2Agent (A2A) Governance, checked 2026-10-29: "Cisco | Luca Muscariello | Distinguished Engineer" — https://raw.githubusercontent.com/a2aproject/A2A/main/GOVERNANCE.md
  40. AGNTCY documentation, home page (docs.agntcy.org), checked 2026-10-29: "AGNTCY is an open source collective building the software components and services that let agents discover each other, verify capabilities, communicate securely, and collaborate across frameworks and organizational boundaries." — https://docs.agntcy.org/
  41. AGNTCY documentation, Translation Service (OASF), checked 2026-10-29: "RecordToA2A translates an OASF record into an A2A card structure." — https://docs.agntcy.org/oasf/translation/
  42. GitHub REST API, repositories of the agntcy organisation, checked 2026-10-29: ""name":"acp-spec"" ""full_name":"agntcy/acp-spec"" — https://api.github.com/orgs/agntcy/repos?per_page=100
  43. Sonika Janagill, Internet of Agents: AGNTCY, Protocols, and Mach Alliance's Agent Ecosystem, December 2025, checked 2026-10-29: "ACP (Agent Connect Protocol) - AGNTCY → Linux Foundation Purpose: Remote agent invocation with thread management Transport: REST/OpenAPI Key Innovation: First-class support for conversational threads and streaming" — https://sonikajanagill.com/articles/architecting-internet-of-agents/
  44. iTechGuides Team, A standard, open framework for building AI agents: AGNTCY explained, 2026-08-18, checked 2026-10-29: "ACP was proposed as a REST/OpenAPI interface for invoking remote agents, but the original ACP specification repository was archived on April 11, 2026." — https://www.itechguides.com/cisco-langchain-and-galileos-agntcy-is-the-standard-open-framework-for-building-ai-agents-here/
  45. Clarion Street, Protocol Engineering: The Standardization Wave Reshaping the Agentic Stack, 2026-09-12, checked 2026-10-29: "The Agent Connect Protocol, ACP, was the other one: a REST interface, specified in OpenAPI, for invoking and configuring remote agents over an API. On April 11, 2026, the owner archived the acp-spec repository read-only." "The repository gives no reason for the archive." — https://www.clarionstreet.com/posts/standardized-agentic-protocols/

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