[BUG] Cowork Windows - Plugins grayed out, plugins.claude.ai does not resolve

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?

In the Cowork Windows app (Pro plan), the Plugins section is grayed out in the Customize panel. Reinstalling does not help. DNS lookup shows that plugins.claude.ai does not resolve, so plugin features and the marketplace do not work.

Related issues reported: #29047 and #28853.

What Should Happen?

The Plugins section should be enabled and allow me to browse and activate plugins. The plugin marketplace should load, and plugins.claude.ai should resolve correctly. Installing plugins should enable slash commands in Cowork conversations.

Error Messages/Logs

No error messages in the app UI, but plugins.claude.ai fails to resolve:

nslookup plugins.claude.ai
Server:  UnKnown
Address:  ...
*** UnKnown can't find plugins.claude.ai: Non-existent domain

Steps to Reproduce

1. Open Cowork on Windows
2. Go to Customize panel
3. Observe Plugins section is grayed out
4. Run nslookup plugins.claude.ai and see it does not resolve
5. Reinstall the Cowork app and confirm problem persists

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.3561.0 (fbc74b)

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

Plan: Pro
App version: 1.3561.0 (fbc74b)
Related issues: #29047 ([BUG] Plugins not loading), #28853 ([BUG] Windows: Cowork plugin marketplace empty — plugins.claude.ai does not resolve)
User attempted full reinstall, issue persists.