[BUG] Bash tool broken on Windows: /usr/bin/bash: -c: line 26: unexpected EOF while looking for matching backtick

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?

Every bash command fails immediately with:
/usr/bin/bash: -c: line 26: unexpected EOF while looking for matching `''

This happens on every command, even trivial ones like echo "hello". The tool was working ~2 days ago and broke after an automatic update.

bash is not installed on the system PATH (Windows) — Claude Code uses its own bundled bash, which appears to have a broken wrapper template.

What Should Happen?

Bash commands execute successfully, as they did ~2 days ago before the automatic update.

Error Messages/Logs

/usr/bin/bash: -c: line 26: unexpected EOF while looking for matching `''

Steps to Reproduce

1. Open Claude Code desktop on Windows 11
2. Ask Claude to run any bash command
3. Every command fails with the above error regardless of content

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Last worked approximately 2 days ago (around June 24, 2026). Broke after an automatic background update. No manual changes were made to the system between the working and broken states.

Claude Code Version

Claude 1.15962.0 (039543) 2026-06-25T01:24:19.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

The bash tool was working normally until ~2 days ago. No manual changes were made to the system. Claude Code auto-updated in the background and the bash tool stopped working after that.

Workaround used: ran Python scripts manually from PowerShell to call gws.exe directly, bypassing the broken bash tool entirely.

Note: the bundled bash Claude Code ships with on Windows is the only bash on this system. Running bash in PowerShell returns "command not found", confirming this is Claude Code's own bundled bash that is broken, not a system bash issue.