[BUG] Windows Shell Compatibility: PowerShell variables (extglob.*) causing command failure

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 Claude Code attempts to execute PowerShell commands that involve variable expansion or filtering (e.g., using Where-Object with $_), the Bash-based tool on Windows incorrectly pre-processes the string. This results in the shell attempting to interpret PowerShell properties as standalone commands, leading to the error:
extglob.Line: The term 'extglob.Line' is not recognized as a name of a cmdlet, function, script file, or executable program.

What Should Happen?

Claude Code should properly escape PowerShell-specific characters (like $) or use a direct execution method that bypasses Bash variable expansion when operating on Windows.

Error Messages/Logs

powershell.exe -Command "Get-Service | Where-Object {$_.Status -ne 'Running'}"

Steps to Reproduce

Run Claude Code on a Windows system using a standard terminal (PowerShell or Windows Terminal).

Ask Claude to perform a task that requires filtering output via PowerShell, such as:

powershell.exe -Command "Get-Service | Where-Object {$_.Status -ne 'Running'}"

Observe the error as the AI repeatedly attempts to execute the command without proper escaping.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

latest as of today

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_