Claude Code /doctor reports duplicate MCP server when plugin is loaded via marketplace #1854

Summary

When chrome-devtools-mcp is installed as a Claude Code plugin via marketplace, /doctor reports:

Plugin Errors
└ 1 plugin error(s) detected:
  └ plugin:chrome-devtools-mcp:chrome-devtools [chrome-devtools-mcp]: MCP server "chrome-devtools" skipped — same command/URL as already-configured "chrome-devtools"

Root Cause

The marketplace structure has source: "./" in marketplace.json, which means the marketplace root directory is the plugin directory. This causes the same plugin.json (containing mcpServers.chrome-devtools) to be loaded twice:

1. First load from ~/.claude/plugins/marketplaces/chrome-devtools-plugins/.claude-plugin/plugin.json
2. Second load from the cached copy at ~/.claude/plugins/cache/chrome-devtools-plugins/chrome-devtools-mcp/latest/.claude-plugin/plugin.json

Both contain the identical mcpServers block:

{
  "mcpServers": {
    "chrome-devtools": {
      "command": "npx",
      "args": ["chrome-devtools-mcp@latest"]
    }
  }
}

The second registration is skipped as a duplicate, producing the warning.

Impact

• Functional: None — the MCP server loads correctly on the first registration
• UX: Persistent error in /doctor output that cannot be resolved by the user

Possible Fix

• Remove mcpServers from plugin.json and keep it only in .mcp.json (or vice versa), ensuring only one source of truth
• Or adjust the caching/loading logic so source: "./" doesn't result in double-loading

Environment

• Claude Code v2.1.104
• macOS (Darwin 25.3.0)
• Plugin version: latest