[BUG] Runaway .output file growth when task repeatedly outputs errors — no size limit or auto-termination

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When a task created via TaskCreate executes a shell command that repeatedly outputs errors in a loop, the .output file
grows indefinitely with no automatic termination and no user notification.

In my case, a PowerShell syntax error (\ being misinterpreted as a command) was emitted on every iteration of a
long-running task. The process ran unattended for ~21 hours, producing a 180 GB output file with no warnings or
safeguards triggered.

What Should Happen?

• Task should auto-terminate when the .output file exceeds a configurable size threshold (e.g. 100 MB)
• Task should auto-terminate when the same error pattern repeats N consecutive times (e.g. 10)
• User should be notified when a task is force-terminated due to these limits
• Limits should be configurable per-session (via CLAUDE.md) or globally (via settings.json):

{
"task": {
"maxOutputSizeMB": 100,
"maxConsecutiveErrors": 10,
"onLimitExceeded": "terminate"
}
}

Error Messages/Logs

Repeated content found in .output file:
  '\' is not recognized as the name of a cmdlet, function, script file, or operable program.
  + \ = 'C:\Users\<user>\fix_planspage.py'
  + ~
      + CategoryInfo          : ObjectNotFound: (\:String) [], CommandNotFoundException
      + FullyQualifiedErrorId : CommandNotFoundException

  Output file location:
  %LOCALAPPDATA%\Temp\claude\<project-slug>\tasks\<task-id>.output

  Output file stats:
  Size:     192,796,228,747 bytes (~180 GB)
  Created:  Day 1, 19:45
  Modified: Day 2, 17:17  (~21 hours of continuous writing)

Steps to Reproduce

1. Open Claude Code on Windows
2. Start a task via TaskCreate that runs a shell command with a syntax error in a loop, e.g.:

Run the following PowerShell command: \ = 'C:\some\script.py'

1. Leave the task running unattended in the background
2. Check %LOCALAPPDATA%\Temp\claude\<project>\tasks\<task-id>.output
3. Observe the file growing continuously with the same error repeated indefinitely

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.45

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_