Agent Skills: Reviewing Plugin Marketplace Configurations

Reviewing Plugin Marketplace Configurations

Comprehensive review of Claude Code plugin marketplace and plugin configurations against official best practices and common pitfalls.

Quick Start

Automated Review (Recommended)

Run the verification script:

bash scripts/verify-marketplace.sh [marketplace-directory]

This automatically checks:

• marketplace.json structure
• Skills paths validation
• Git remote URL
• README.md repository references
• plugin.json presence (warns if exists)

Manual Review

1. Ask user for marketplace directory (e.g., .claude-plugin/)
2. Read marketplace.json and plugin.json (if exists)
3. Check against official format and common errors
4. Provide detailed feedback with priorities

Example review output:

## Critical Issues
- ❌ Repository URL mismatch: README.md uses "owner-a/repo" but marketplace.json uses "owner-b/repo"
- ❌ Source path "./.claude-plugin" does not exist

## Important Issues
- ⚠ plugin.json exists but Anthropic's official format uses marketplace.json only
- ⚠ Skills path "./skills/missing-skill" not found

## Compliance Score
- Structure: ✓ Valid JSON
- Required fields: ✓ Present
- Path validation: ✗ 2 invalid paths

Review Process

Step 1: Read Configuration Files

Read and analyze:

• .claude-plugin/marketplace.json (required for marketplaces)
• .claude-plugin/plugin.json (optional, check if present)
• README.md (for repository URL consistency)
• Git remote URL (if in git repository)

Step 2: Validate marketplace.json Structure

Required fields:

• [ ] name - Marketplace identifier
• [ ] owner.name - Owner name
• [ ] plugins - Array of plugin definitions

Each plugin must have:

• [ ] name - Plugin identifier
• [ ] source - Source path (must start with ./, e.g., "./plugins/plugin-name")
• [ ] description - What the plugin does

Recommended fields:

• [ ] metadata.description - Marketplace description
• [ ] metadata.version - Version number

Note: skills field specifies skills directory path (root-relative, e.g., "./plugins/plugin-name/skills/")

Optional fields (context-dependent):

• [ ] strict: false - Only needed if plugins lack plugin.json files (see references/common-errors.md)

Step 3: Check Common Errors

Repository URL consistency:

• Compare URLs in marketplace.json, plugin.json, README.md, git remote
• All should point to the same repository
• Common issue: Using organization name instead of personal username

Source path validation:

• Verify source path exists
• Must start with ./ (e.g., "./plugins/plugin-name")
• Check that source directory contains skills/ subdirectory with SKILL.md files

Skills path validation:

• Verify skills path exists (root-relative, e.g., "./plugins/plugin-name/skills/")
• Directory should contain subdirectories with SKILL.md files

plugin.json conflicts:

• Anthropic's official format uses marketplace.json only
• Having both may cause confusion
• If both exist, ensure names match

README.md consistency checks:

• Skills documentation: Verify all skills in marketplace.json are documented in README.md
  • Check "Skills Included" section lists each skill from the skills array
  • Each skill should have description and "Use when" guidance
• Project Structure accuracy:
  • If plugin.json mentioned in README but doesn't exist, suggest using marketplace.json
  • Verify structure diagram matches actual files in .claude-plugin/
• Permissions section completeness:
  • Check if README.md settings.json examples include all skills from marketplace.json
  • Example: "Skill(skill-name)" for each skill should be in permissions array
• Repository references: Ensure consistent GitHub URLs across README installation examples

Step 4: Compare with Anthropic Format

See references/anthropic-format.md for official structure.

Key patterns from Anthropic:

• marketplace.json at .claude-plugin/marketplace.json
• No plugin.json (marketplace.json only)
• source: "./plugins/plugin-name" pointing to plugin directory (must start with ./)
• strict: false (optional - only needed when plugin.json is missing)
• skills field specifies skills directory (root-relative path)

Step 5: Generate Feedback

Organize findings by priority:

Critical Issues (breaks functionality):

• enabledPlugins format error (array instead of object)
• Repository URL mismatch with git remote
• Invalid source path (doesn't exist)
• Missing required fields
• Invalid JSON syntax

Important Issues (causes confusion):

• Repository URL inconsistency across files
• Invalid skills paths
• Conflicting plugin.json and marketplace.json
• Missing recommended fields

Suggestions (best practices):

• Add metadata section (improves discoverability)
• Add strict: false only if plugins lack plugin.json (otherwise no effect)
• Follow Anthropic's single-file pattern
• Explicit skills array

Common Issues Reference

See references/common-errors.md for detailed error patterns and solutions.

Top 3 issues from real experience (by actual impact):

1. enabledPlugins format error ⚠️ BREAKS FUNCTIONALITY

   • Error: Plugins don't load, no activation
   • Cause: Using array ["plugin@marketplace"] instead of object {"plugin@marketplace": true}
   • Fix: Change to object format in settings.json
   • This is the #1 cause of "plugin not working" issues

2. Repository URL mismatch

   • Error: Plugin 'name' not found in marketplace
   • Cause: README/settings use different owner than actual git remote
   • Fix: Ensure all URLs match git remote -v

3. Wrong source path

   • Error: Plugin 'name' not found
   • Cause: Source points to non-existent directory
   • Fix: Use "./" for root, verify path exists

Output Format

Structure review with these sections:

• Summary: Overall assessment
• Critical Issues: Must fix (with file:line references)
• Important Issues: Should fix (with explanations)
• Suggestions: Best practices alignment
• Compliance Score: Quick visual assessment

Tips for Effective Reviews

Be Specific: Don't say "URL is wrong" - say "marketplace.json line 7 uses 'owner-a/repo' but git remote shows 'owner-b/repo'"

Verify Paths: Actually check if files/directories exist, don't just validate format

Check Consistency: Cross-reference all files that mention repository URLs

Use Official Examples: Compare against Anthropic's format at https://github.com/anthropics/skills

References

Anthropic Format: See references/anthropic-format.md for official marketplace.json structure

Common Errors: See references/common-errors.md for detailed error patterns and solutions