Claude Code plugin marketplace fails to load - listAvailablePlugins validation error #33068

Environment

• OS: Windows 11 (10.0.26100)
• Claude Desktop: Latest version (as of 2026-03-11)
• Claude Code (CCD): v2.1.72

Description

The Claude Code plugin marketplace tab fails to load with a validation error. The Cowork plugin marketplace works fine, but the Claude Code ("By Anthropic") plugin marketplace shows a blank/error state.

Error from logs

claude.ai-web.log shows repeated errors:

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

Root Cause Analysis

After investigation, the issue is a schema mismatch between the Claude Desktop app's validation schema and the data in the official marketplace repository (claude-plugins-official).

In marketplace.json, many external/third-party plugins are missing the author field, which the desktop app's schema validation requires. Affected plugins include:

• atlassian, figma, Notion, sentry, slack, vercel, pinecone
• huggingface-skills, circleback, superpowers, posthog, coderabbit
• sonatype-guide, firecrawl, qodo-skills, semgrep, postman
• greptile, serena, playwright, github, supabase, asana
• linear, gitlab, laravel-boost, firebase, context7, stripe

Only the Anthropic first-party plugins (LSP servers, code-review, commit-commands, etc.) have the author field.

Example - plugin WITH author (works):

{
  "name": "typescript-lsp",
  "description": "TypeScript/JavaScript language server...",
  "author": {
    "name": "Anthropic",
    "email": "support@anthropic.com"
  },
  "source": "./plugins/typescript-lsp"
}

Example - plugin WITHOUT author (causes validation failure):

{
  "name": "atlassian",
  "description": "Connect to Atlassian products...",
  "category": "productivity",
  "source": {
    "source": "url",
    "url": "https://github.com/atlassian/atlassian-mcp-server.git"
  }
}

Steps to Reproduce

1. Open Claude Desktop on Windows
2. Go to Settings → Plugins → Claude Code tab
3. The marketplace fails to load
4. Check logs at %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\claude.ai-web.log
5. Observe repeated listAvailablePlugins failed to pass validation errors

Expected Behavior

The Claude Code plugin marketplace should load and display all available plugins.

Suggested Fix

Either:

1. Add the author field to all external plugins in marketplace.json, OR
2. Make the author field optional in the desktop app's validation schema for listAvailablePlugins