[BUG] Account plugin "Design" can't be removed or disabled: claude.ai Remove is a no-op and Desktop Code sessions keep loading it

Summary

On claude.ai → Customize → Plugins → Yours, removing or disabling the Anthropic Design plugin (plugin_01XXJmxLXPEhPMmnxmrgntNw, marketplace knowledge-work-plugins) reports success, but the plugin stays enabled on the account and Claude Desktop keeps loading it into every Code session. The local enabledPlugins switch doesn't stop it either, so there is currently no way to turn it off.

Environment

• Windows 11 (build 26340), Claude Desktop 2.19675.0.0 (MSIX), bundled Claude Code 2.1.286; CLI 2.1.289
• Max plan, personal account
• Observed 4 Oct 2026

Steps and results

1. Remove. Customize → Plugins → Yours → Design → ⋮ → Remove → confirm.

• Toast: "Design has been removed".
• Request sent: PUT /api/organizations/<org>/plugins/plugin_01XXJmxLXPEhPMmnxmrgntNw/enabled → 200.
• After a reload the plugin is still listed and its page still shows the toggle on. Tried twice, same result.

1. Toggle off on the plugin's own page ("Enable plugin").

• Same PUT …/enabled → 200.
• GET /plugins/plugin_01XXJmxLXPEhPMmnxmrgntNw now returns enabled: false.
• GET /plugins/list-plugins?enabled_only=true and GET /library/mine?kind=plugin still return Design with enabled: true more than 15 minutes later.

1. New Desktop Code session. It still loads the plugin's 7 design:* skills and its 9 MCP servers (7 "needs authentication"; google calendar and gmail fail with "No URL configured").
2. Local switch. claude plugin disable design@synced sets "design@synced": false under enabledPlugins in ~/.claude/settings.json, and claude plugin list shows it disabled, but a new Desktop Code session still loads it.

Expected

Remove takes the plugin off the account, or the toggle disables it everywhere; the list endpoints reflect it; Desktop Code sessions stop loading it. Failing that, enabledPlugins: { "<name>@synced": false } should be honoured in Desktop sessions.

Also

• The plugin record is source: default, marketplace_kind: anthropic_catalog, installation_preference: available, can_remove: true, can_toggle: true.
• Plugin Management (cowork-plugin-management) is returned by library/mine and loaded into sessions, but hidden from the Yours list, so the UI has no Remove or toggle for it at all.