[BUG] Bash tool returns no output on Windows - all shells affected, WSL works

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?

On Windows, the Bash tool returns "(Bash completed with no output)" for ALL commands. Commands execute correctly, only stdout capture is broken. Tested Git Bash, CMD (cmd /c), and changing $SHELL to the Git bin wrapper. All fail. A separate Claude Code install on WSL/Ubuntu works perfectly. When commands run on Windows, a brief popup window appears for the child process, suggesting it gets its own console instead of inheriting pipes.

What Should Happen?

Bash tool should capture and return stdout on Windows, same as on macOS/Linux/WSL.

Error Messages/Logs

Steps to Reproduce

1. Launch Claude Code on Windows (any terminal)
2. Run ! echo hello or ! curl -I https://example.com
3. Returns "(Bash completed with no output)"
4. Same command in WSL Claude install works fine

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.112

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Terminal/Shell:
Windows Terminal + Git Bash, also tested CMD and PowerShell

Additional Information:

▎ - Windows 11 Enterprise 10.0.26100
▎ - Git for Windows bash at C:\Program Files\Git\usr\bin\bash.exe
▎ - File redirect workaround works: command > file.txt 2>&1 then Read tool
▎ - WSL works perfectly, confirming the capture logic is fine, the issue is Windows-specific pipe/ConPTY handling