MCP server 'claude_design' (frontend-design plugin): 404 Streamable HTTP error

Environment

• Claude Code on Windows 11 Pro
• Plugin: frontend-design@claude-plugins-official

Issue

The claude_design MCP server consistently fails with:

Streamable HTTP error: Error POSTing to endpoint: 404 page not found

Steps to reproduce

1. Enable the frontend-design@claude-plugins-official plugin in settings.json
2. Run /doctor — the server reports the above 404 error

What I tried

• Disabled and re-enabled the plugin in settings.json
• Restarted Claude Code

The error persists. This appears to be a server-side issue with the plugin endpoint.