[BUG] Skill Installer Silent Failure

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?

Product: Cowork (desktop, Windows)
Version: Current as of May 2026
Severity: Medium — no data loss, but causes persistent incorrect state and wastes significant user time

Issue 1: .skill Installer Silently Fails When Skills Folder is Read-Only

What Should Happen?

Expected behavior: The skill is installed. The installed file reflects the updated content.

Actual behavior: The installer appears to succeed. No error is shown. The installed skill file on disk is unchanged. The new session reads the old skill.

Error Messages/Logs

**Root cause (identified via diagnostic):**

The skills folder is mounted read-only inside the Cowork session environment:


fuse (ro,nosuid,nodev,...) on /sessions/.../mnt/.claude/skills


The installer cannot write to a read-only mount. It does not surface this as an error.

Steps to Reproduce

Steps to reproduce:

1. Build or update a skill, package it as a .skill file
2. Click "Save Skill" in the Cowork install dialog
3. Open a new session and ask Claude to read the installed skill

Expected behavior: The skill is installed. The installed file reflects the updated content.

Actual behavior: The installer appears to succeed. No error is shown. The installed skill file on disk is unchanged. The new session reads the old skill.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.719.0 (2dbd78(

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

The installer cannot write to a read-only mount. It does not surface this as an error.

Workaround: Manually navigate to the skills folder on disk and replace the SKILL.md file directly. On Windows, the path follows this pattern:

C:\Users\[username]\AppData\Roaming\Claude\local-agent-mode-sessions\skills-plugin\[workspace-id]\[user-id]\skills\[skill-name]\SKILL.md

This path is not documented anywhere in the UI and requires running diagnostic mount commands inside a session to discover.

Time lost: Multiple sessions across one week attempting to diagnose why skill updates were not taking effect.