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

[QuintonDesigns]

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?

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)

[github-actions]

Closing for now — inactive for too long. Please open a new issue if this is still relevant.

[wg-1424]

Confirming this is still happening (Cowork, July 2026) — same symptom as this report: deleted a
skill via Customize > Skills, confirmed it was fully gone (absent from a fresh session's skill
list and from the local manifest.json snapshot), then tried to reinstall a corrected version under
the identical name and got "This skill name is already in use. Try a different name."

One additional data point that might help narrow down the cause: the Skills API docs
(platform.claude.com/docs/en/api/beta/skills/create and .../delete) describe skills as versioned
resources — deleting a skill via the API requires deleting all of its versions first, then the
skill object itself; deleting with versions still attached errors out. That suggests the
Customize > Skills UI "delete" action may only be removing the skill from the visible list (or its
current version) without purging every version server-side, leaving a version record that still
reserves the name even though the skill is gone everywhere a user can see it.

Workaround: packaged the skill under a new name instead of the original — worked fine, but meant
updating every other skill/doc that referenced the old name by exact string.

This was closed as not_planned — reopening for consideration given it's still reproducible and the
UI gives no way to fully deregister a name once it's stuck.