[BUG] Skills on Claude ai dissapeared, stopped working, or can't be uploaded

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?

Skills on Claude ai dissapeared, stopped working, or can't be uploaded.

• In case of upload - Internal server error
• In case of viewing the skills - document not found
• Or it simply states that skill is non existing despite I see it.

What Should Happen?

Internal server error

Error Messages/Logs

Steps to Reproduce

Create a skill
Run it
Cry

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 4.6

Platform

Other

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_