Claude Plugin Validation

Overview

This skill provides comprehensive validation for Claude Code plugins to ensure they meet official development guidelines, prevent installation failures, and maintain compatibility across different versions. It focuses on critical validation areas that commonly cause plugin breakage.

When to Apply

Use this skill when:

• Preparing a plugin for release
• Debugging plugin installation failures
• Updating plugin structure or manifest
• Validating compatibility with Claude Code versions
• Conducting quality assurance checks
• Investigating plugin loading issues

Claude Code Plugin Guidelines Validation

1. Plugin Manifest (plugin.json) Validation

Critical Requirements:

• Required Fields: name, version, description, author
• Valid JSON Syntax: Must pass JSON parsing without errors
• Semantic Versioning: Use x.y.z format (no pre-release identifiers)
• Version Consistency: Must match version references in documentation
• Character Encoding: UTF-8 encoding required
• File Size: Under 1MB recommended for performance

Validation Checks:

{
  "required_fields": ["name", "version", "description", "author"],
  "optional_fields": ["repository", "license", "homepage", "keywords"],
  "version_pattern": "^\\d+\\.\\d+\\.\\d+$",
  "max_file_size": 1048576,
  "encoding": "utf-8"
}

Common Issues that Cause Installation Failures:

• Missing required fields
• Invalid JSON syntax (trailing commas, unescaped characters)
• Incorrect version format
• Special characters in description without proper escaping
• File encoding issues

2. Directory Structure Validation

Required Structure:

plugin-root/
├── .claude-plugin/
│   └── plugin.json          # Plugin manifest (REQUIRED)
├── agents/                  # Agent definitions (optional)
├── skills/                  # Skill definitions (optional)
├── commands/                # Command definitions (optional)
└── lib/                    # Python utilities (optional)

Validation Rules:

• .claude-plugin/plugin.json must exist and be valid JSON
• Directory names must match plugin system conventions
• Files must use .md extension for agents/skills/commands
• No circular directory references
• Proper case sensitivity handling

3. File Format Compliance

Agent Files (agents/*.md):

---
name: agent-name
description: When to invoke this agent (action-oriented)
tools: Read,Write,Edit,Bash,Grep,Glob  # optional
model: inherit  # optional
---

# Agent Title

Core responsibilities...

## Skills Integration
Reference skills by name...

## Approach
Detailed instructions...

## Handoff Protocol
How to return results...

Skill Files (skills/*/SKILL.md):

---
name: Skill Name
description: What this skill provides (200 char max)
version: 1.0.0
---

## Overview
What, when, and why...

## Domain-Specific Sections
2-5 sections with guidelines, examples, standards...

## When to Apply
Trigger conditions...

Command Files (commands/*.md):

• Should not start with dot (.)
• Must contain usage examples
• Should include ## Usage section
• Must be valid Markdown

4. YAML Frontmatter Validation

Required YAML Structure:

---
name: string           # Required for agents/skills
description: string    # Required for agents/skills
version: string       # Required for skills
tools: array          # Optional for agents
model: string         # Optional for agents
---

YAML Validation Rules:

• Valid YAML syntax (no tabs for indentation)
• Proper string escaping
• No duplicate keys
• Valid data types (string, array, etc.)
• UTF-8 encoding

5. Cross-Platform Compatibility

File Path Handling:

• Use forward slashes in documentation
• Handle Windows path separators (\) in scripts
• Case sensitivity considerations
• Maximum path length (260 chars Windows, 4096 Linux/Mac)

Character Encoding:

• All files must be UTF-8 encoded
• No BOM (Byte Order Mark)
• Proper Unicode handling in JSON
• Escape special characters correctly

Line Ending Compatibility:

• Git configuration: git config --global core.autocrlf false
• Use LF line endings in source files
• Batch scripts: CRLF endings required
• Shell scripts: LF endings required

6. Plugin Dependency Validation

External Dependencies:

• List all Python dependencies in requirements
• Validate package availability and versions
• Check for conflicting dependencies
• Ensure cross-platform package availability

Claude Code Compatibility:

• Check for deprecated Claude Code features
• Validate agent tool usage
• Ensure skill loading compatibility
• Verify command naming conventions

7. Installation Failure Prevention

Pre-Installation Validation:

# Validate plugin before distribution
python -c "
import json
import os

# Check plugin manifest
try:
    with open('.claude-plugin/plugin.json', 'r') as f:
        manifest = json.load(f)
    required = ['name', 'version', 'description', 'author']
    missing = [field for field in required if field not in manifest]
    if missing:
        print(f'Missing required fields: {missing}')
        exit(1)
    print('✅ Plugin manifest valid')
except Exception as e:
    print(f'❌ Plugin manifest error: {e}')
    exit(1)

# Check file encoding
for root, dirs, files in os.walk('.'):
    for file in files:
        if file.endswith(('.json', '.md', '.py')):
            filepath = os.path.join(root, file)
            try:
                with open(filepath, 'r', encoding='utf-8') as f:
                    f.read()
            except UnicodeDecodeError:
                print(f'❌ Invalid encoding: {filepath}')
                exit(1)
print('✅ File encoding valid')
"

Common Installation Failure Causes:

1. JSON Syntax Errors: Trailing commas, unescaped quotes
2. Missing Required Fields: name, version, description, author
3. Invalid Version Format: Using semantic versioning incorrectly
4. File Encoding Issues: Non-UTF-8 encoded files
5. Path Length Issues: Exceeding system path limits
6. Permission Problems: Incorrect file permissions
7. Case Sensitivity: Mismatched file/directory names

8. Version Compatibility Matrix

Claude Code Version Compatibility:

Plugin Breaking Changes:

• Manifest schema changes
• Agent tool requirement changes
• Skill loading modifications
• Command naming updates

9. Quality Assurance Checklist

Pre-Release Validation:

• Plugin manifest validates with JSON schema
• All required fields present and valid
• YAML frontmatter validates in all .md files
• File encoding is UTF-8 throughout
• Directory structure follows conventions
• Version numbers are consistent
• No broken file references
• Cross-platform path handling
• Installation test on clean environment
• Documentation accuracy verification

Automated Validation Script:

# Full plugin validation
def validate_plugin(plugin_dir="."):
    issues = []

    # 1. Manifest validation
    manifest_path = os.path.join(plugin_dir, ".claude-plugin", "plugin.json")
    if not validate_manifest(manifest_path):
        issues.append("Invalid plugin manifest")

    # 2. Directory structure
    if not validate_structure(plugin_dir):
        issues.append("Invalid directory structure")

    # 3. File format validation
    if not validate_file_formats(plugin_dir):
        issues.append("File format issues found")

    # 4. Encoding validation
    if not validate_encoding(plugin_dir):
        issues.append("File encoding issues found")

    return issues

# Usage
issues = validate_plugin()
if issues:
    print("Validation failed:")
    for issue in issues:
        print(f"  ❌ {issue}")
    exit(1)
else:
    print("✅ Plugin validation passed")

10. Troubleshooting Installation Failures

Debug Steps:

1. Check Plugin Manifest:

   python -m json.tool .claude-plugin/plugin.json
   

2. Validate File Encoding:

   find . -type f -name "*.md" -exec file {} \;
   

3. Check Directory Structure:

   tree .claude-plugin/ agents/ skills/ commands/
   

4. Test Installation:

   # Test in clean directory
   mkdir test-plugin && cp -r . test-plugin/
   cd test-plugin
   # Try installation here
   

Common Error Solutions:

• "Plugin failed to load": Check JSON syntax and required fields
• "Agent not found": Verify agent file naming and structure
• "Skill loading failed": Check YAML frontmatter syntax
• "Command not available": Verify command file format

Implementation Guidelines

Validation Implementation Steps

1. Manifest Schema Validation:

   • Load and validate JSON against known schema
   • Check required fields and data types
   • Validate version format and consistency

2. Structure Validation:

   • Verify required directories exist
   • Check file naming conventions
   • Validate agent/skill/command file formats

3. Content Validation:

   • Parse YAML frontmatter in markdown files
   • Validate required YAML fields
   • Check file encoding throughout

4. Compatibility Testing:

   • Test with different Claude Code versions
   • Validate cross-platform compatibility
   • Check for deprecated feature usage

Error Handling

Error Categories:

• Critical: Installation-blocking issues (JSON syntax, missing manifest)
• Warning: Non-critical issues (missing documentation, style issues)
• Info: Informational findings (optimization suggestions)

Error Recovery:

• Auto-fix common JSON syntax issues
• Generate missing required fields with defaults
• Normalize file encodings automatically
• Suggest improvements for warnings

Integration with Existing Tools

This skill complements the existing plugin_validator.py by adding:

• Claude Code-specific validation rules
• Installation failure prevention focus
• Version compatibility checking
• Cross-platform compatibility validation
• Schema validation for plugin manifests

Use this skill together with the general plugin validator for comprehensive quality assurance.

Version: 1.0.0 Last Updated: 2025-10-23 Compatible With: Claude Code Plugin System v2.0+