Repomix Configuration Skill

This skill provides .repomix.config.json template and validation logic for AI-friendly codebase compression.

Purpose

Manage .repomix.config.json to:

• Achieve 70% token reduction through XML compression
• Configure repository-type-specific include patterns
• Integrate with .gitignore for automatic exclusions
• Exclude build artifacts and prevent recursion
• Enable automatic security checks for sensitive data

Usage

This skill is invoked by the repomix-config-agent when:

• Creating new .repomix.config.json files
• Auditing existing Repomix configurations
• Validating .repomix.config.json against standards

Templates

Repository-type-specific templates are located in:

templates/.repomix.config.json.template

The 5 Repomix Standards

Rule 1: XML Output Format (CRITICAL)

Must configure XML output with compression:

{
  "output": {
    "filePath": ".repomix-output.txt",
    "style": "xml",
    "showLineNumbers": true,
    "compress": true
  }
}

Requirements:

• style: "xml" - Enables Tree-sitter compression (70% token reduction vs plain text)
• compress: true - Activates compression
• showLineNumbers: true - Maintains code traceability
• filePath: ".repomix-output.txt" - Standard output location

Validation:

# Check XML output configuration
grep -q '"style": "xml"' .repomix.config.json || echo "VIOLATION: Missing XML format"
grep -q '"compress": true' .repomix.config.json || echo "VIOLATION: Compression disabled"
grep -q '"showLineNumbers": true' .repomix.config.json || echo "VIOLATION: Line numbers disabled"

Rule 2: Include Patterns by Repository Type (CRITICAL)

Must configure include patterns matching repository type:

Validation:

# For Turborepo (example)
grep -q '"apps/\*\*"' .repomix.config.json || echo "VIOLATION: Missing apps/** pattern"
grep -q '"packages/\*\*"' .repomix.config.json || echo "VIOLATION: Missing packages/** pattern"

Rule 3: Gitignore Integration

Must enable gitignore and default patterns:

{
  "ignore": {
    "useGitignore": true,
    "useDefaultPatterns": true
  }
}

Settings explained:

• useGitignore: true - Automatically respects .gitignore patterns
• useDefaultPatterns: true - Includes Repomix default exclusions

Validation:

# Check gitignore integration
grep -q '"useGitignore": true' .repomix.config.json || echo "VIOLATION: Gitignore disabled"
grep -q '"useDefaultPatterns": true' .repomix.config.json || echo "VIOLATION: Default patterns disabled"

Rule 4: Exclude Patterns (CRITICAL)

Must exclude build artifacts and prevent recursion:

{
  "ignore": {
    "customPatterns": [
      "node_modules/**",
      ".git/**",
      "dist/**",
      "build/**",
      ".turbo/**",
      ".next/**",
      "coverage/**",
      ".repomix-output.*",
      "*.log"
    ]
  }
}

Critical exclusions:

• .repomix-output.* - Prevents including previous outputs (recursion)
• Build artifacts - Reduces noise and context size
• Log files - Excludes runtime logs

Validation:

# Check critical exclusions
grep -q '".repomix-output.\*"' .repomix.config.json || echo "VIOLATION: Missing .repomix-output.* exclusion"
grep -q '"node_modules/\*\*"' .repomix.config.json || echo "VIOLATION: Missing node_modules exclusion"

Rule 5: Security Check

Must enable automatic security scanning:

{
  "security": {
    "enableSecurityCheck": true
  }
}

Validation:

# Check security enabled
grep -q '"enableSecurityCheck": true' .repomix.config.json || echo "VIOLATION: Security check disabled"

Repository Type Detection

Use /skill scope-check to determine repository type if not provided.

Validation

To validate .repomix.config.json:

1. Check that file exists at repository root
2. Detect repository type
3. Read .repomix.config.json content
4. Validate against 5 standards
5. Verify include patterns match repository type
6. Check .gitignore excludes .repomix-output.*
7. Report violations

Validation Approach

# Check file exists
[ -f ".repomix.config.json" ] || echo "VIOLATION: Missing .repomix.config.json at root"

# Rule 1: XML output
grep -q '"style": "xml"' .repomix.config.json || echo "VIOLATION: Missing XML format"
grep -q '"compress": true' .repomix.config.json || echo "VIOLATION: Compression disabled"

# Rule 2: Include patterns (repo-specific)
# Example for Turborepo
grep -q '"apps/\*\*"' .repomix.config.json || echo "VIOLATION: Missing apps/** pattern"

# Rule 3: Gitignore integration
grep -q '"useGitignore": true' .repomix.config.json || echo "VIOLATION: Gitignore disabled"

# Rule 4: Exclude patterns
grep -q '".repomix-output.\*"' .repomix.config.json || echo "VIOLATION: Missing output exclusion"

# Rule 5: Security
grep -q '"enableSecurityCheck": true' .repomix.config.json || echo "VIOLATION: Security disabled"

# Check .gitignore
grep -q ".repomix-output.\*" .gitignore || echo "VIOLATION: .gitignore missing .repomix-output.* exclusion"

Repository Type Considerations

• Turborepo: Includes apps, packages, services
• Library: Focuses on packages and components
• Plugin Marketplace: Includes plugins and .claude-plugin
• Python: Includes tools, providers, .py files
• Shell: Includes scripts and .sh files

Best Practices

1. Root only - .repomix.config.json at repository root
2. Match repo type - Use appropriate include patterns
3. Always exclude .repomix-output.* - Prevents recursion
4. Enable compression - Critical for 70% token reduction
5. Update .gitignore - Add .repomix-output.* exclusion
6. Re-audit after changes - Verify compliance
7. Use security check - Auto-detect sensitive data

.gitignore Integration

CRITICAL: Always add to .gitignore:

# Repomix output
.repomix-output.*

This prevents committing compressed output to version control.

Integration

This skill integrates with:

• Repository type provided via scope parameter. If not provided, use /skill scope-check
• /skill audit-workflow - Bi-directional comparison workflow
• /skill remediation-options - Conform/Update/Ignore choices