[BUG] UNC paths in working directories cause settings.json permissions to be ignored

[queglay]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Description:

Claude Code silently ignores permission rules in settings.json / settings.local.json when the resolved working directory is a UNC path (e.g., \server\share\path).

Environment:

OS: Windows 10 (Cygwin/MSYS2 shell)
Claude Code: VSCode extension

Actual behavior:

Claude Code prompts for permission on every tool call as if no allow rules exist. The settings.json permissions are silently ignored — no warning or error is logged.

Root cause hypothesis:

Path matching for permission rules likely uses string comparison or glob matching that doesn't account for UNC paths (\host\share...). Windows working directories can resolve to UNC paths when the workspace is on a network share, even if the user accesses it via a mapped drive letter. The mismatch between the UNC-resolved path and the drive-letter-based paths in settings causes all permission lookups to fail.

Workaround:

Ensure all configured working directories resolve to mapped drive letters rather than UNC paths, or avoid adding UNC paths to the additionalWorkingDirectories configuration.

Additional context:

This is particularly impactful on Windows in enterprise/VFX environments where network shares are common. The failure is silent — there's no indication that permissions were skipped due to path resolution, making it difficult to diagnose.

What Should Happen?

Permission rules from settings.json are respected and matching tool calls proceed without prompting.
Claude should respect permissions for UNC paths like the ones below:

      "Write(**)",
      "Write(//*/**)",

Error Messages/Logs

No error log, just being prompted for permisison

Steps to Reproduce

Reproduction steps:

Configure settings.json (global or project-level) with permission allow rules
Open Claude Code in a workspace where the working directory resolves to a UNC path (e.g., \server\share... rather than a mapped drive letter like S:...)
Use tools that should be permitted by the settings
use plan mode to execute anything with auto-accept and permissive settings.json files will be ignored.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

2.1.5

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. Bug: Incorrect project config path created for UNC paths on Windows #22529
2. [BUG] Path construction bug on Windows with UNC paths - prevents access to conversation history #14403
3. [BUG] --resume fails on Windows with Google Drive mapped drives — CWD resolves to C:\Windows instead of actual path #26815

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
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🤖 Generated with Claude Code

[queglay]

None of those issues match the permissions issues described, and none of them are active.

[palmkevin]

I observed the same problem: Permission glob matching does not normalize UNC path separators on Windows

Summary
On Windows, Claude Code fails to auto-approve a Read tool call even when a matching permission rule exists, because the glob matcher does not normalize UNC path separators (\ vs /) before comparing.

Environment
Platform: Windows (network share via UNC path)
Shell: Git Bash
OS: Windows Server 2019
Settings
settings.json contains both UNC path formats:

"Read(//myserver/lx/release/)",
"Read(\\myserver\lx\release\)"
The second entry decodes from JSON to \myserver\lx\release**.

Steps to Reproduce
Add the above two Read permission entries to settings.json.
Have Claude invoke the Read tool with a backslash UNC path, e.g. \myserver\lx\release\kpa\python32...\fct_executor.py.
Observe that Claude Code still prompts for permission instead of auto-approving.
Expected Behavior
Both \myserver\lx\release** and //myserver/lx/release/** should match any file under that share, regardless of which separator style the requested path uses. The matcher should normalize separators before comparing.

Actual Behavior
The permission prompt fires even though a matching rule exists — the matcher treats \ and / as distinct characters with no normalization step

[emilytocin]

I observed the same problem, and wound up granting MUCH WIDER permissions than I was comfortable with to workaround the issue.