[BUG] Desktop plugin browser (Discover) does not list uninstalled plugins from configured marketplaces, a plugin uninstalled from the UI can never be reinstalled from the UI

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?

The Desktop app's plugin browser only shows plugins that are already installed. Plugins that exist in a configured marketplace's catalog but are not installed do not appear anywhere in the UI, so they cannot be discovered or installed from the app. The CLI installs the exact same plugins without any problem.

The practical consequence: uninstalling a plugin from the Desktop UI is a one-way door. After "Elimina", the plugin disappears and there is no UI path to get it back.

What Should Happen?

Environment
Claude Code 2.1.246 (bundled in Desktop; also reproduced with the standalone CLI)
Windows 11 Pro 26200, Claude Desktop
Personal Max plan, no managed settings, no managed-settings.json anywhere on the machine
10 marketplaces registered, including claude-plugins-official (auto-registered)
Minimal reproduction

Expected
Discover lists plugins available in the configured marketplaces regardless of install state, so they can be installed from the app.

Error Messages/Logs

Actual
Only installed plugins are listed. The rest of the catalog is invisible — for claude-plugins-official that is 497 catalog entries of which only the installed ones appear.

Evidence that the catalog is intact
~/.claude/plugins/marketplaces/claude-plugins-official/.claude-plugin/marketplace.json contains the missing plugins: hookify at line 1742 with "source": "./plugins/hookify", plus ralph-loop, kotlin-lsp and others.
claude plugin marketplace update claude-plugins-official reports success and does not change the file — the catalog was already current.
Removing and re-adding the marketplace (fresh git clone) did not change the symptom.
The CLI installs any of these plugins on request, from the same catalog.
Also reproduced on claude.ai (web)
The same subset is missing in the browser on claude.ai, which shares no local state with this machine. Only plugins installed via CLI are visible there too. This suggests the discovery surface is shared between Desktop and web, and that both list installed plugins rather than the catalog.

Ruled out
Each of these was tested and did not change the behaviour:

marketplace cache — verified twice, refreshed explicitly, then removed and re-cloned
Electron renderer cache — Cache, Code Cache, GPUCache, Local Storage, IndexedDB, Session Storage and others deleted with the app fully closed
full app restart from the system tray (verified no claude.exe left running)
stale install manifests — 15 orphaned files in ~/.claude/plugins/.install-manifests for plugins uninstalled long ago; unrelated, and present before the symptom appeared
local policy — no managed-settings.json in %ProgramData%, %ProgramFiles% or ~/.claude; no strictKnownMarketplaces, disableClaudeAiConnectors or similar keys in settings.json
Impact
New plugins cannot be discovered or installed from the app at all — only from the CLI.
Uninstalling from the UI is irreversible from the UI. A user without the CLI loses the plugin permanently.
The two surfaces disagree about what exists, which makes the app's plugin manager unreliable as a source of truth.

Steps to Reproduce

Using ralph-loop, which had never been installed on this machine:

1. claude plugin install ralph-loop@claude-plugins-official → appears in the UI, enabled
2. toggle it off in the UI → still listed, shown as OFF
3. "Elimina" (uninstall) in the UI → disappears from the UI entirely
4. search for it in Discover → NOT FOUND
5. try to install it from the UI → NOT POSSIBLE
6. claude plugin install ralph-loop@claude-plugins-official → works again, reappears

Steps 4 and 5 are the bug. Step 6 proves the catalog and the plugin are fine.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.237

Claude Code Version

2.1.246

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Notes
The symptom appeared after the Desktop update on 2026-08-26/27; before that the plugin browser listed catalog plugins normally. During the update claude-code moved to 2.1.246 while a separate bundled component (claude-code-vm) remained at 2.1.237 dated four days earlier, which may or may not be related.