[BUG] "Update" Tool Fails on Additional Working Directory (WSL)

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

Claude Code consistently fails when attempting to use an "Update" tool on files in an additional
working directory on WSL. The error message shown is "Error editing file" with no additional
details. The workaround is to use Read followed by Edit/Write, which always succeeds.

Environment

• Claude Code Version: 2.0.29
• Platform: WSL2
• OS: Linux 5.15.167.4-microsoft-standard-WSL2
• Installation: npm-global

Configuration

• Main working directory: /mnt/c/Users/jhall26/Dropbox/Research/RSUE_Uber
• Additional working directory: /mnt/c/Users/jhall26/Dropbox/Apps/Overleaf/RSUE paper on

Ride-hailing

• Global settings: Only alwaysThinkingEnabled: true configured
• No MCP servers, no plugins, no hooks configured

Steps to Reproduce

1. Set up a project with an additional working directory on a WSL /mnt/c/... path
2. Ask Claude to edit a file in the additional working directory
3. Observe "Update" tool failure with "Error editing file"

Expected Behavior

Files in additional working directories should be editable using the same tools/mechanisms as
files in the main working directory.

Actual Behavior

• In additional directory (/mnt/c/.../Overleaf/...): "Update" tool fails with "Error editing

file"

• In main directory (/mnt/c/.../Research/RSUE_Uber/...): Edit tool works successfully

UI Message Displayed

● Update(/mnt/c/Users/jhall26/Dropbox/Apps/Overleaf/RSUE paper on Ride-hailing/main.tex)
⎿ Error editing file

● Read(/mnt/c/Users/jhall26/Dropbox/Apps/Overleaf/RSUE paper on Ride-hailing/main.tex)
⎿ Read 20 lines

Observations

1. The "Update" tool is not a user-configured tool - it appears to be an internal tool or UI

display issue

1. Files have correct permissions (777, writable - verified with test -w and stat)
2. The workaround (Read → Edit/Write) always succeeds, suggesting the issue is not with file

permissions

1. Happens every time - 100% reproducible
2. Only affects the additional working directory, not the main directory

Workaround

Claude automatically falls back to using Read followed by Edit/Write operations, which succeeds.
However, this wastes tokens and adds latency on every edit attempt.

Possible Root Causes

• Internal UI displaying "Update" instead of "Edit" for operations in additional directories
• Bug in how Claude Code handles file operations across multiple working directories
• WSL path handling issue specific to secondary directories

What Should Happen?

Expected Behavior

Files in additional working directories should be editable using the same tools/mechanisms as
files in the main working directory.

Error Messages/Logs

● Update(/mnt/c/Users/jhall26/Dropbox/Apps/Overleaf/RSUE paper on
Ride-hailing/main.tex)
  ⎿  Error editing file

● Read(/mnt/c/Users/jhall26/Dropbox/Apps/Overleaf/RSUE paper on Ride-hailing/main.tex)
  ⎿  Read 20 lines

Steps to Reproduce

1. Set up a project with an additional working directory on a WSL /mnt/c/... path
2. Ask Claude to edit a file in the additional working directory
3. Observe "Update" tool failure with "Error editing file"

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.29 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_