Undefined Progress Indicator in Claude Code CLI

Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/2795
2. https://github.com/anthropics/claude-code/issues/4788
3. https://github.com/anthropics/claude-code/issues/3517

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🤖 Generated with Claude Code

Hey there,

I saw your issue and thought I'd chime in as another user. Based on your error log, I have a pretty good idea of what might be happening. Great job including the logs, by the way, that stdout maxBuffer length exceeded error is the key clue!

This issue usually points to a problem with a custom status line script.

Claude Code has a cool feature (introduced in version 1.0.71) that lets you create a custom status line at the bottom of the UI, much like a custom shell prompt (PS1). You can set it up with the /statusline command. This feature works by running a shell script in the background and using its output for the status text.

Here's my theory:

1. You likely have a custom status line script configured.
2. That script is either erroring out or, more likely, printing a huge amount of text to standard output.
3. The Claude Code process that runs the script has a buffer limit for how much output it can read. Your script is exceeding that limit, which is causing the stdout maxBuffer length exceeded error you're seeing.
4. When that child process fails, the main Claude Code app doesn't receive a valid string for the status, so the UI just displays undefined.

How to Fix It

Here are the steps I'd recommend to troubleshoot and fix this:

1. Check your settings file for a statusLine configuration. Look in either your user settings (~/.claude/settings.json) or your project-specific settings (<your-project>/.claude/settings.json). You're looking for a block that looks like this:

``json
"statusLine": {
"type": "command",
"command": "/path/to/your/statusline-script.sh"
}
``

1. Temporarily disable it. The quickest way to confirm if this is the problem is to just comment out or delete that entire "statusLine": { ... } block from your settings file and restart claude. If the undefined message goes away, you've found the culprit!

1. Debug your status line script. If you want to keep using a custom status line, you'll need to fix the script itself.

• Find the script located at the path in the "command" field.
• Run it manually in your terminal: sh /path/to/your/statusline-script.sh
• The script should only output a single, short line of text. If it's printing a lot of data (like the contents of a large file, a long log, etc.), that's your problem.
• A quick fix could be to pipe the output of your script to head -n 1 directly in your settings.json file to ensure only the first line is ever used.

Hope this helps you get it sorted

I temporarily disabled the statusLine and restarted Claude Code just to see the undefined... pop up as the message again.

@coygeek I don’t think this is related to the statusline. People have disabled it or never configured it, and it still shows as undefined.

I’ve set up a pretty fancy status line with ANSI colors and all that. It’s just one line and fairly short, so I’m not sure what the issue is. Either way, I’m looking forward to getting it resolved 👍

By the way, the new animation on the flavor text is amazing. The left-to-right highlighting looks great.

Never configured it, and has the issue. Came up after the recent update. Was working well before.
Only "Compacting Conversation" works. Everything else "undefined"

I'm seeing this too, but no errors. Kinda infuriating. I do not have a status line configured and have never set one up.

<img width="750" height="138" alt="Image" src="https://github.com/user-attachments/assets/e5ad6055-c00f-4987-9b5e-ccc5c2951f10" />

Same issue here for days.

<img width="1776" height="324" alt="Image" src="https://github.com/user-attachments/assets/5be25548-5a92-41ea-bae5-c9ac043c2a05" />

Yep, we are now at version 1.0.86 and no change. Is this a macOS thing, or do people on other platforms also experience this?

I am on windows platform and am wondering what does "undefined" mean

Yep, we are now at version 1.0.86 and no change. Is this a macOS thing, or do people on other platforms also experience this?

Getting it in windows 11 as well.

Macos here

On Fri, 22 Aug 2025, 3:02 pm jomon003, @.***> wrote:

jomon003 left a comment (anthropics/claude-code#5951) <https://github.com/anthropics/claude-code/issues/5951#issuecomment-3213041835> Yep, we are now at version 1.0.86 and no change. Is this a macOS thing, or do people on other platforms also experience this? Getting it in windows 11 as well. — Reply to this email directly, view it on GitHub <https://github.com/anthropics/claude-code/issues/5951#issuecomment-3213041835>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAUAM7T2CF52I27VSMPVOYL3O2P6DAVCNFSM6AAAAACECD44XOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTEMJTGA2DCOBTGU> . You are receiving this because you commented.Message ID: @.***>

I am on windows platform and am wondering what does "undefined" mean

Most likely it's the fallback to not being able to fetch the action verbs. As the property is not assigned, its default value is undefined.

Now how this is happening and why, no idea.

<img width="240" height="107" alt="Image" src="https://github.com/user-attachments/assets/f0c4fc88-ec36-4584-a0a2-96f4e3bf88e5" />

In my situation, I resolved the issue by performing a clean reinstall of Claude Code. Before doing so, I backed up the existing configuration files by renaming .claude.json, claude.backup.json, and the .claude folder with a (backup) suffix as a precaution. After the reinstall, I allowed Claude Code to regenerate these files and folders from scratch, which fixed the problem.

<img width="726" height="110" alt="Image" src="https://github.com/user-attachments/assets/edde7ff1-adb7-4ae5-bd7d-a7420c9f8b50" />

With the latest version of Claude Code (1.0.90), the action verbs no longer show up for me as undefined. I did not change anything in my config, and CC updated automatically. Anyone else?

Still reproducible with 1.0.90 on macOS for me.
Processing starts as one of the usual verbs, but then switches to undefined, which may or may not be new behavior since this version.

Noticed this occurring in 1.0.90. I have never set a custom statusline, nor is there any statusline stuff in my config file.

+1. Windows 11 and WSL, with CC running using the VSCode extension. I never configured a status line or anything like that.

Still happening on 1.0.112. Using macos. Never had status line configured. Downgrading to 1.0.80 fixes it but I'd like to upgrade at some point to get updates. I get the issue on 1.0.81+

Still seeing this on 2.0.22 on macOS.

I was able to resolve this by uninstalling and reinstalling. I had a global installation at one point that would've worked for all users and I migrated it to a personal installation at one point when it recommended doing that. I think it was the doctor command if I recall that suggested switching to a local install. I'm guessing there was something left over from the old installation that was preventing it from working. It's been a while and I can't remember exactly what I did but I think either run the npm uninstall command, or maybe reinstalling and uninstalling the global npm one.

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