Cowork: Personal marketplace plugin installation lost after app restart

Description

Third-party plugins installed from the Personal marketplace tab in Cowork do not persist after restarting Claude Desktop. The marketplace itself persists, but the plugin must be re-installed every time.

Steps to Reproduce

1. Open Claude Desktop → Cowork tab
2. Go to Customize → Browse plugins → Personal tab
3. Click "+" → Add marketplace from GitHub (e.g., owner/repo)
4. Marketplace syncs successfully and plugin appears
5. Click Install on the plugin — it installs and works correctly
6. Quit Claude Desktop (Cmd+Q) and reopen
7. Go back to Customize → Browse plugins → Personal tab
8. Plugin shows "Install" button again — installation was lost

Expected Behavior

Plugin installation should persist across restarts, just like it does for the Claude Code (Code tab / CLI).

Actual Behavior

• The marketplace persists (the pill in the Personal tab survives restart)
• The plugin installation is lost (shows "Install" button again)
• User must re-install the plugin after every restart

Environment

• Claude Desktop: macOS (latest version as of 2026-03-29)
• Plugin name: datarails-financeos (kebab-case, passes claude plugin validate)
• Marketplace source: GitHub repository with .claude-plugin/marketplace.json

Additional Context

• Installing the same plugin via CLI (claude plugin install datarails-financeos@datarails-marketplace) persists correctly across restarts in the Code tab
• The CLI install writes to ~/.claude/plugins/installed_plugins.json and enabledPlugins in ~/.claude/settings.json — both show the plugin correctly after CLI install
• But the Cowork tab does not recognize the CLI-installed plugin and still shows "Install"
• This suggests Cowork and Claude Code have separate plugin installation state that is not synchronized

Workaround

Users must re-install the plugin from the Personal tab after each restart, or use the Code tab instead of Cowork.

Related Issues

• #14815 — Plugins show as "(installed)" but don't appear in Installed tab
• #29936 — Custom Cowork plugin commands wiped by Claude Desktop update
• #24433 — "Always allow" for MCP tools does not persist across Cowork sessions