Definition
What is ACP, the Agent Client Protocol?
The Agent Client Protocol is a general interface that lets an editor drive any conforming coding agent, so Zed or a JetBrains IDE can use several agents through one integration. Bridges expose Muse Code over ACP. Anything ACP has no vocabulary for, such as Muse Code specific usage reporting, has to be approximated.
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The tradeoff
| General protocol (ACP) | Native protocol (MSP) | |
|---|---|---|
| Agents supported | Many | Muse Code |
| Editor integration | Write once for all agents | Per agent |
| Feature fidelity | Lowest common denominator | Everything the agent exposes |
| New agent capability | Waits for the protocol to grow | Available when the SDK has it |
When each is right
If you want one editor panel that can drive whichever agent you are paying for this month, a general protocol is exactly right. If you want a client that surfaces one agent completely, including its approval modes and its usage reporting, a native protocol client is the one that can do it.
Source: Overview - Agent Client Protocol
Frequently asked questions
Does Helicon use ACP?
No. Helicon is a Muse Code Session Protocol client and talks to muse serve directly.
Can I use an ACP editor and Helicon together?
Yes. They share the same CLI and login, and sessions are discoverable either way.
Is one protocol better?
They answer different questions. Breadth across agents, or depth on one.
Keep reading
- the Muse Code Session ProtocolMSP is the JSON-RPC protocol that applications use to drive a Muse Code session over stdio, instead of parsing terminal output. What it carries and why it matters.
- Zed with ACPRunning Muse Code inside Zed through an Agent Client Protocol bridge, compared with a standalone Muse Code desktop app. Editor native versus session native.
- JetBrains IDEsMuse Code inside IntelliJ, PyCharm, GoLand or WebStorm through an Agent Client Protocol plugin, compared with a standalone Muse Code desktop app.
- an ADEAn ADE is the workspace you supervise coding agents from, the way an IDE is the workspace you write code in. What belongs in one and what does not.
- agent approvalsAn approval is the moment an agent asks before acting. The three Muse Code modes, what each one does, and why bypassing them is the wrong optimisation.
- a git worktreeA git worktree is a second working directory for the same repository. It is the cheapest way to stop two coding agents from editing the same files.
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