Desktop: 'Browse plugins' fails with listAvailablePlugins validation error

Environment

• Claude Desktop: v1.1.7464
• Claude Code CLI: v2.1.79
• macOS: Darwin 24.1.0
• Plan: Max (Vita)

Description

The "Browse plugins" modal in Claude Desktop (Code tab) fails to load with a persistent validation error. The plugin system works correctly via CLI (claude plugins list) and the Desktop main process logs show successful marketplace refresh. The error occurs only in the web renderer IPC call.

Error Message

Error invoking remote method '$eipc_message$_..._$_claude.web_$_CustomPlugins_$_listAvailablePlugins': 
Error: Result from method "listAvailablePlugins" in interface "CustomPlugins" failed to pass validation

Steps to Reproduce

1. Open Claude Desktop → Code tab
2. Click "+" or open Browse plugins
3. Error appears immediately, with skeleton loading or "Failed to load marketplaces"

What I've Tried (none resolved the issue)

• Force quit and restart Desktop
• Cleared Desktop Electron cache (~/Library/Caches/com.anthropic.claudefordesktop/)
• Removed stale plugin cache versions (kept only active versions)
• Emptied extraKnownMarketplaces in settings.json (error persists even with only claude-plugins-official)
• Removed broken firebase@firebase marketplace entry and data
• Cleaned up orphaned temp_git_* directories
• Validated all JSON files (installed_plugins.json, known_marketplaces.json, settings.json, all plugin.json and marketplace.json files) — all valid
• Clicked "reinstall the workspace" link in error message — no visible effect

Key Finding

• claude plugins list via CLI works perfectly
• Desktop main.log shows successful marketplace refresh: [CCDMarketplacePluginManagerCLI] Marketplace refreshed: claude-plugins-official
• Error is isolated to the web renderer's IPC validation of listAvailablePlugins result
• This indicates the IPC schema in the web renderer is stricter than what the main process returns

Relevant Logs

main.log (no errors):

[CCDMarketplacePluginManagerCLI] Refreshing marketplace: claude-plugins-official
[marketplaceFileOps] Synthesized plugin.json for firecrawl (strict:false marketplace plugin)
[marketplaceFileOps] Synthesized plugin.json for superpowers (strict:false marketplace plugin)
[CCDMarketplacePluginManagerCLI] Marketplace refreshed: claude-plugins-official

claude.ai-web.log (error):

[REACT_QUERY_CLIENT] QueryClient error: Error: Error invoking remote method '..._CustomPlugins_$_listAvailablePlugins': Error: Result from method "listAvailablePlugins" in interface "CustomPlugins" failed to pass validation