[BUG] Cygwin: CWD temp file path missing /cygdrive prefix

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 Cygwin (Windows), the Claude Code shell integration layer writes a CWD-tracking temp file using the Windows-mapped path (e.g., /c/cygwin64/tmp/claude-xxxx-cwd) instead of the Cygwin-translated path (/cygdrive/c/cygwin64/tmp/claude-xxxx-cwd). Bash then fails to read the file and produces an error after every single Bash tool invocation:

/usr/bin/bash: line 1: /c/cygwin64/tmp/claude-xxxx-cwd: No such file or directory

What Should Happen?

The Cygwin-translated path (/cygdrive/c/cygwin64/tmp/claude-xxxx-cwd) should be used and the error should not occur.

Error Messages/Logs

The error reported is:

/usr/bin/bash: line 1: /c/cygwin64/tmp/claude-xxxx-cwd: No such file or directory

Steps to Reproduce

1. Open Cygwin terminal (Mintty)
2. Run claude
3. Request an action that requires Claude to execute a command.

Claude Model

Opus

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

Previously reported as #49704, but erroneously marked as a duplicate and closed.