@agentclientprotocol/claude-agent-acp@0.25.3 referenced in registry does not exist on npm

[sambic-mike]

Description

I am attempting to use the Claude agent in Zed, but it fails to load. After investigating the Zed logs it appears that the ACP registry is pointing to version 0.25.3 of @agentclientprotocol/claude-agent-acp, which doesn't seem to have been published to npm.

Zed fetches the registry dynamically at runtime and attempts to install the specified version via npx — it looks like because the version doesn't exist, the Claude agent fails to load. The latest version I can find on npm is 0.25.0. I may be wrong but it seems like the registry entry may have been updated before the corresponding npm package was published?

Steps to reproduce:

1. Open Zed and attempt to launch the Claude agent
2. Zed fetches https://cdn.agentclientprotocol.com/registry/v1/latest/registry.json and attempts to install @agentclientprotocol/claude-agent-acp@0.25.3 via npx
3. Install fails

Evidence:

The registry specifies:

"distribution": {
    "npx": {     
        "package": "@agentclientprotocol/claude-agent-acp@0.25.3"
    }
}

Confirmed 0.25.3 does not appear to exist on the public npm registry (bypassing any corporate proxies with explicit --registry flag):

$ npm view @agentclientprotocol/claude-agent-acp@0.25.3 --registry [https://registry.npmjs.org/](https://registry.npmjs.org/)
npm error code E404
npm error 404 No match found for version 0.25.3
npm error 404 The requested resource '@agentclientprotocol/claude-agent-acp@0.25.3' could not be found or you do not have permission to access it.

The latest version I can find on npm is 0.25.0:

$ npm view @agentclientprotocol/claude-agent-acp --registry [https://registry.npmjs.org/](https://registry.npmjs.org/)
@agentclientprotocol/claude-agent-acp@0.25.0 | Apache-2.0 | deps: 3 | versions: 4

Zed logs confirm the failure:

npm error code ETARGET
npm error notarget No matching version found for @agentclientprotocol/claude-agent-acp@0.25.3.
npm error notarget In most cases you or one of your dependencies are requesting a package version that doesn't exist.

Expected behaviour:
The registry should reference a version that has been published to npm.

Suggested fix:
It would be great if the registry entry could be updated to reference @agentclientprotocol/claude-agent-acp@0.25.0 until 0.25.3 is published to npm, or alternatively if 0.25.3 could be published.

I appreciate that Zed could also handle this more gracefully by verifying a version exists before attempting to install it, or by falling back to the latest available version, I am going to raise there also.

[sambic-mike]

Also raised on zed-industries/zed#53309

[justindocanto]

Found a cause, at least for me, to this issue. I was seeing the "failed to launch. internal error. server shut down unexpectedly" issue last week and again this morning. Trying to debug things this morning, logs said it could not find 0.25.3

After attempting the usual remedies (update Zed, try a nightly build, re-install the agent, re-authenticate, etc) I noticed my log was also saying with a date before 3/31/2026, 6:35:56 AM

Full line:
2026-04-07T06:35:56-07:00 WARN [agent_servers::acp] agent stderr: npm error notarget No matching version found for @agentclientprotocol/claude-agent-acp@0.25.3 with a date before 3/31/2026, 6:35:56 AM

And then it clicked. I have min-release-age=7 in my ~/.npmrc file for the project I had open. It seems to be affecting Zeds npm actions.

I opened a new project and confirmed claude worked fine. I went back to the project I was working on, removed min-release-age=7 from my .npmrc file, re-opened Zed, and Claude works fine. Obviously not ideal, but editing the file before/after opening Zed seems to be a temporary fix.

[benbrandt]

This should be fixed in zed-industries/zed#55770