[BUG] / plugins

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?

Title: /plugin command fails with "Invalid schema" errors for multiple plugins

Body:
## Description
Running /plugin fails to load the marketplace with schema validation errors.

## Error Message
Failed to load all marketplaces. Errors: claude-plugins-official: Invalid schema:
plugins.56.source: Invalid input, plugins.63.source: Invalid input,
plugins.67.source: Invalid input, plugins.71.source: Invalid input,
plugins.72.source: Invalid input, plugins.73.source: Invalid input,
plugins.74.source: Invalid input, plugins.75.source: Invalid input,
plugins.81.source: Invalid input

## Environment

• OS: macOS (Darwin 25.3.0)
• Date observed: 2026-03-17

## Expected Behavior
The plugin marketplace should load successfully.

## Actual Behavior
Multiple plugins (indices 56, 63, 67, 71-75, 81) have invalid source field values that fail schema validation, preventing the marketplace from loading.

What Should Happen?

/plugins should load

Error Messages/Logs

/plugin                                                                                                                                                           
  ⎿  Failed to load all marketplaces. Errors: claude-plugins-official: Invalid schema: plugins.56.source: Invalid input, plugins.63.source: Invalid input,        
     plugins.67.source: Invalid input, plugins.71.source: Invalid input, plugins.72.source: Invalid input, plugins.73.source: Invalid input, plugins.74.source:     
     Invalid input, plugins.75.source: Invalid input, plugins.81.source: Invalid input

Steps to Reproduce

/plugin

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.31

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_