ACP Registry Is Live: Zed and JetBrains Just Did for AI Agents What LSP Did for Language Servers

The Agent Client Protocol registry — launched January 28, 2026 by JetBrains and Zed Industries — is a curated directory of AI coding agents that install natively into both IDEs without per-editor configuration.¹² As of April 20, 2026, it holds 40+ registered agents.³ If you have been maintaining separate Claude Code, Codex, or Gemini integrations for each editor, there is now a single registration path that covers both — but migration has nuance worth understanding before you commit.

What ACP Actually Is (and What It Isn’t)

The Agent Client Protocol (ACP) is an IDE-to-agent integration layer: it defines how a coding agent communicates with a host IDE, analogous to how the Language Server Protocol (LSP) defines how a language server communicates with an editor. Just as LSP let language server authors write once and reach every LSP-compatible editor, ACP lets agent authors register once and appear natively in every ACP-compatible IDE.

That analogy matters because “ACP” is ambiguous in the wild. IBM’s BeeAI project defines an entirely separate “Agent Communication Protocol” — also abbreviated ACP — that handles agent-to-agent messaging, not IDE integration. The two protocols are unrelated. Generic coverage conflates them regularly; anything you read about IBM BeeAI’s ACP is describing a different specification.

ACP is also distinct from MCP (Model Context Protocol), Anthropic’s tool-use and context-injection layer. MCP connects agents to external data sources and tools; ACP connects agents to IDEs. They operate at different layers and are not substitutes.

The Registry in Practice: How Agents Get Listed and How You Install Them

Distribution runs through a CDN at cdn.agentclientprotocol.com. Agent versions auto-update hourly via a cron job that polls npm, PyPI, and GitHub releases.³ From an end-user perspective, installed agents stay current without manual intervention.

Registering a new agent requires forking github.com/agentclientprotocol/registry, adding a directory containing an agent.json manifest and an optional icon.svg, then opening a pull request.⁴ CI validates schema compliance, slug uniqueness, icon format, URL accessibility, and binary OS coverage before merge. The submission process is deliberately conservative — the result is a curated list rather than an open package registry.

In both JetBrains and Zed, installation happens through the IDE’s agent picker rather than a marketplace. In Zed, agents auto-install on first use and authenticate via /login in a new thread.⁵

Supported Agents and Version Requirements

Zed

Zed requires version 0.202.7 or later. Claude Agent installs as @zed-industries/claude-acp; Codex installs as codex-acp (version 0.208+). Both auto-install on first use and authenticate via /login.⁵

JetBrains

JetBrains requires IDE version 2025.3.2 or later, plus AI Assistant plugin version 253.30387.147 or later.² No JetBrains AI subscription is required — authentication is handled by each agent provider’s own service.

As of March 2026, Cursor joined the registry and is available inside JetBrains IDEs through the agent picker, combining Cursor’s agentic workflows with JetBrains code intelligence.⁶ No JetBrains subscription is required for Cursor either.⁶ The Cursor addition is notable because Cursor is itself a competing IDE — its decision to join as an agent rather than a host signals that ACP has reached an adoption threshold where participation makes sense even for parties with competing interests.

Migration Path: From Per-Editor Integrations to ACP

The coexistence window is currently open. If you have an agent installed through both a legacy per-editor extension and the ACP registry, the registry version takes precedence.¹ Old Agent Extensions will eventually be deprecated, but no hard deadline has been announced as of 2026-04-20.

This means the practical migration path is non-disruptive: install the registry version alongside your existing integration, verify it behaves as expected, and then remove the legacy extension at your own pace. You are not forced to cut over immediately.

Docker’s Contribution: cagent and YAML-Defined Agents

Docker’s cagent is an open-source, YAML-based agent builder that ships with ACP support. It is bundled in Docker Desktop 4.49.0 and later.⁷ An agent defined as a YAML file runs inside any ACP-compatible IDE with a single command:

cagent acp <file>.yaml

Docker’s role here is ecosystem contribution — cagent is an ACP-compatible tool, not a co-authorship of the protocol itself. The protocol was built by JetBrains and Zed; Docker joined as a participant.

Known Limitations

Two gaps are worth planning around before committing to ACP as your primary integration layer:

No thread history resume. ACP sessions do not persist conversation history between IDE sessions. Each new thread starts fresh. If your workflow depends on resuming long-running context across sessions, native integrations (where available) may still handle this better.

No past-message editing. You cannot edit a previous message in an ACP agent thread. This is a limitation relative to some native integrations and chat interfaces.

Neither limitation is a blocker for most coding workflows, but teams that have built workflows around session continuity should evaluate the gap before migrating.

Should You Standardize on ACP Today?

The registry is stable enough to adopt. The CDN distribution, hourly auto-updates, and PR-based registration process are all production-grade infrastructure choices. Cursor’s March 2026 addition — a competing IDE joining as an agent — is the clearest signal that ACP has reached a point where major actors are treating it as a durable standard rather than an experiment.

The case for waiting is thin. The coexistence window means migration carries minimal risk today. The known limitations (no thread resume, no message editing) are real but narrow. For teams running separate Claude, Codex, and Gemini configurations per editor, consolidating to ACP reduces maintenance surface without meaningful capability loss for the majority of coding workflows.

The one genuine caveat: if your team relies on VS Code as a primary editor, ACP coverage there is still community-driven rather than officially supported. Multi-editor teams spanning VS Code and JetBrains or Zed should factor that asymmetry into their timeline.

FAQ

Is ACP the same as MCP? No. MCP (Model Context Protocol) is a tool-use and context-injection layer that connects agents to external data sources and services. ACP (Agent Client Protocol) is an IDE-integration layer that connects agents to editors. They operate at different levels of the stack and are complementary, not redundant.

Do I need a JetBrains subscription to use registry agents in a JetBrains IDE? No. Access to the ACP registry does not require a JetBrains AI subscription. Each agent authenticates through its own provider’s service.²⁶

How do I register my own agent? Fork github.com/agentclientprotocol/registry, add a directory with an agent.json manifest and optional icon.svg, and open a pull request. CI validates schema compliance, slug uniqueness, icon format, URL accessibility, and binary OS coverage before the PR is merged.⁴

What happens to my existing agent extensions during migration? Registry-installed and extension-installed versions of the same agent coexist during the transition window. When both are present, the registry version takes precedence. Legacy Agent Extensions are planned for eventual deprecation, though no firm timeline has been set as of 2026-04-20.¹

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