[BUG] Write/Edit tools fail with EEXIST on non-OneDrive directories (C: drive)

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?

##Description

The EEXIST regression introduced in v2.1.69 (reported in #30928 as OneDrive-specific) also affects regular local directories on C: with no OneDrive involvement.

Environment

• Claude Code version: 2.1.69 (or later)
• OS: Windows 11 Pro 10.0.26200
• Shell: bash (Git Bash)
• Working directory: C:\second-brain\bike-tracker (local NTFS, not OneDrive-synced)

Relation to #30928

That issue attributes the root cause to OneDrive ReparsePoint directories. This case has no OneDrive involvement — suggesting the mkdir logic regression is broader than OneDrive.

What Should Happen?

Expected behavior

Write/Edit should succeed on plain local directories, as they did in v2.1.68 and earlier.

Error Messages/Logs

Error: EEXIST: file already exists, mkdir 'C:\second-brain\bike-tracker'

Steps to Reproduce

Reproduction

1. Working directory is a plain local folder on C:
2. Read a file using the Read tool → succeeds
3. Attempt to Edit or Write to that same file

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.68

Claude Code Version

2.1.69

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_