[BUG] Skill name conflict persists after full local cleanup — registry appears server-side

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?

Installing a skill fails with "This skill name is already in use. Try a different name." even after completely removing all local traces of the skill name.

What I tried (none resolved the error)

Deleted the skills/[skill-name] folder from the installed plugin directory
Deleted ~/Library/Application Support/Claude/Local Storage/ entirely
Removed "[skill-name]" from the skillUsage field in all .claude.json files across every session workspace under ~/Library/Application Support/Claude/local-agent-mode-sessions/
Restarted Claude Desktop multiple times
Restarted the computer
Checked IndexedDB, WebStorage, Partitions, and cowork-enabled-cli-ops.json

What Should Happen?

Removing the skill and clearing local storage should allow reinstalling a skill with the same name. Alternatively, the UI should surface a way to fully deregister a skill name.

Error Messages/Logs

This skill name is already in use. Try a different name.

Steps to Reproduce

1. Install a skill via the Cowork UI
2. Remove the skill (or attempt to)
3. Try to reinstall a skill with the same name

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Desktop (Cowork mode) v1.10628.2 (deee0a)

Platform

Other

Operating System

macOS

Terminal/Shell

Other

Additional Information

Additional finding
The "Remove" button for skills in the Settings UI does not fully deregister the skill name. The conflict error still appears after using it.
Environment

Platform: macOS
App: Claude Desktop (Cowork mode) v1.10628.2 (deee0a)