[BUG] /plugin marketplace fails to load — schema validation error on source field

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?

Running /plugin shows this error:

Failed to load marketplace "claude-plugins-official" from source (github):
Failed to parse marketplace file: Invalid schema: plugins.2.source: Invalid input,
plugins.5.source: Invalid input, plugins.12.source: Invalid input (14 entries total)

Root cause: the official marketplace.json on GitHub uses a new source object format:
{ "source": "url", "url": "https://github.com/...", "sha": "..." }
but Claude Code schema validator expects source to be a plain string.

What Should Happen?

The /plugin marketplace browser loads successfully and displays available plugins without schema validation errors.

Error Messages/Logs

Failed to load marketplace "claude-plugins-official" from source (github): Failed to parse marketplace file at
  /Users/.../.claude/plugins/marketplaces/anthropics-claude-plugins-official/.claude-plugin/marketplace.json: Invalid schema:
  plugins.2.source: Invalid input, plugins.5.source: Invalid input, plugins.12.source: Invalid input, plugins.29.source: Invalid input,
  plugins.49.source: Invalid input, plugins.58.source: Invalid input, plugins.64.source: Invalid input, plugins.67.source: Invalid input,
  plugins.89.source: Invalid input, plugins.99.source: Invalid input, plugins.108.source: Invalid input, plugins.116.source: Invalid input,
  plugins.117.source: Invalid input, plugins.122.source: Invalid input

Steps to Reproduce

1. Open Claude Code
2. Run /plugin
3. Error appears immediately — marketplace fails to load

Note: Plugin installation via direct command still works:
claude plugin install figma@claude-plugins-official

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.117

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Deleting the cached marketplace folder and restarting does not help, the file is re-downloaded from GitHub with the same new schema format that fails validation. Updating Claude Code to latest (2.1.117) did not resolve the issue.