[Bug] Plugin manifest validation error: Unrecognized keys "category" and "source"

Bug Report: Marketplace Plugins Fail to Load Due to Unrecognized Manifest Keys

Summary

The atlassian and superpowers marketplace plugins fail to load on every terminal startup with a manifest validation error citing unrecognized keys (category, source). Reinstalling the plugins does not resolve the issue.

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Steps to Reproduce

1. Install the atlassian and/or superpowers plugins from the marketplace
2. Close and reopen Claude Code in the terminal
3. Observe the plugin error banner on startup

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Expected Behavior

Plugins installed from the official marketplace should load without validation errors.

Actual Behavior

Both plugins fail to load on every startup with the following error:

✘ marketplace-plugin
  Plugin superpowers has an invalid manifest file at
  /Users/abhishek.nilange/.claude/plugins/cache/claude-plugins-official/superpowers/4.3.1/.claude-plugin/plugin.json

  Validation errors: Unrecognized keys: "category", "source"
  Please fix the manifest or remove it. The plugin cannot load with an invalid manifest.

✘ marketplace-plugin
  Plugin atlassian has an invalid manifest file at
  /Users/abhishek.nilange/.claude/plugins/cache/claude-plugins-official/atlassian/5fa435362b2c/.claude-plugin/plugin.json

  Validation errors: Unrecognized keys: "category", "source"
  Please fix the manifest or remove it. The plugin cannot load with an invalid manifest.

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Root Cause (suspected)

The plugin manifests published to the marketplace include category and source fields, but the manifest schema validator in Claude Code 2.1.50 does not recognize these keys, causing validation to fail. This appears to be a schema mismatch between the plugin publisher and the client-side validator.

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Troubleshooting Already Attempted

• [x] Reinstalled both plugins multiple times via the marketplace
• [x] Cleared plugin cache at ~/.claude/plugins/cache/claude-plugins-official/
• [x] Confirmed Claude Code is on the latest version (2.1.50)

None of the above resolved the issue — the invalid manifests are re-downloaded on reinstall.

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Environment

| Field | Value |
|---|---|
| Claude Code Version | 2.1.50 |
| Platform | macOS (darwin) |
| Terminal | VS Code integrated terminal |
| Feedback ID | c845ddbc-dcce-4423-8332-42600e06f438 |

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Relevant Error Logs

{
  "error": "Error: Marketplace 'mavvrik-claude-plugins' is already installed. Please remove it first using '/plugin marketplace remove mavvrik-claude-plugins' if you want to re-install it.",
  "timestamp": "2026-03-03T11:39:39.057Z"
}