[BUG] Cowork "Add a folder to this session" incorrectly blocks project root due to overly broad "protected location" check

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?

Related to #73852 (same root cause — a static path-pattern check on "add folder to ongoing session" rejects any folder containing a protected-looking subpath, not an actual filesystem check). Filing separately since this confirms the same defect on a different pattern trigger (.claude/skills) and I wanted to register it as an independent occurrence.

When adding a workspace folder to a Home-tab Cowork session ("Add a folder to this session"), selecting a project root directory is rejected if it contains a .claude/skills subdirectory (even when that subdirectory is a symbolic link pointing elsewhere). The error shown is: "That folder overlaps a protected location (<path>\.claude\skills) and can't be used here. Choose a different folder."

This worked previously — I was able to select this same project folder as the workspace before a recent app update (today's update brought the Desktop app to version 1.30096.5.0).

What Should Happen?

The "protected location" check should only exclude the skills subdirectory itself from the session's read/write scope, not reject the entire ancestor directory. Many users intentionally keep a project's Claude skills folder inside the project root (a common, documented personal/team skill-management pattern) — the project root itself should still be selectable as a workspace folder.

Error Messages/Logs

That folder overlaps a protected location (D:\<project>\.claude\skills) and can't be used here. Choose a different folder.

Steps to Reproduce

1. Have a project directory whose .claude\skills path is a symbolic link pointing to (or is itself) a Claude skills directory
2. In Claude Desktop, go to a Home-tab task and click "Add a folder to this session"
3. Browse to and select the project root directory (the one containing .claude\skills)
4. Click "Select Folder"
5. Observe the error: "That folder overlaps a protected location (...\.claude\skills) and can't be used here."

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — worked prior to today's auto-update to Desktop app 1.30096.5.0

Claude Code Version

2.1.229 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

Note: this bug is in the Claude Desktop app's Cowork "Add a folder to this session" GUI feature, not a terminal/CLI interaction — the Terminal/Shell field above isn't directly applicable, PowerShell is just my default shell environment on this machine.

Desktop app version: 1.30096.5.0 (Windows)

Claude Code CLI version bundled with Desktop app: 2.1.229 (latest on npm is 2.1.233, published 3 days ago — this is the Desktop-app-managed bundled CLI, not a standalone npm install I control directly). The Desktop app itself auto-updated to 1.30096.5.0 today.

Related but distinct issues: #78547, #81121