Repomix

Convert any repository into a single optimized file that LLMs can fully understand for code review, documentation, and analysis.

What This Skill Does

The Challenge: LLMs have context window limits and can’t load entire repositories. Feeding code piecemeal loses cross-file context, making analysis shallow and documentation incomplete.

The Solution: Repomix packs entire repositories into a single XML/Markdown file with smart filtering, token optimization, and metadata. LLMs receive full codebase context for accurate analysis, documentation, and code generation.

Activation

Implicit: Activates when performing full codebase analysis, generating repository documentation, or feeding codebases to LLMs.

Explicit: Activate via prompt:

Activate repomix skill to pack our frontend repository for codebase analysis

Capabilities

1. Repository Packing

Convert entire repo to single AI-optimized file.

# Pack current directory
npx repomix

# Pack specific directory
npx repomix --include "src/**,package.json,README.md"

# Remote repository
npx repomix --remote https://github.com/owner/repo

Output formats: XML (default, best for LLMs), Markdown, plain text

2. Smart Filtering

Include only relevant files for efficient token usage.

# Exclude patterns
npx repomix --ignore "*.test.ts,dist/**,node_modules/**"

# Include only specific paths
npx repomix --include "src/**/*.ts,src/**/*.tsx"

Auto-excluded by default: node_modules, .git, build artifacts, lock files

3. Token Optimization

Count tokens before feeding to LLM to avoid context overflow.

# Show token count without generating file
npx repomix --token-count

Token targets by model:

4. Security Scanning

Detect secrets and sensitive data before packing.

# Enable security check
npx repomix --security-check

Detects: API keys, passwords, tokens, private keys, connection strings

Prerequisites

• Node.js 18+
• Git repository to pack

Configuration

.repomixignore file (project root):

# Similar to .gitignore
*.env
*.env.local
secrets/
*.key
coverage/

repomix.config.json:

{
  "output": {
    "format": "xml",
    "filePath": "repomix-output.xml"
  },
  "ignore": {
    "useGitignore": true,
    "customPatterns": ["*.test.ts", "*.spec.ts"]
  }
}

Best Practices

1. Always run security check first Never pack a repo without checking for leaked secrets. Add .repomixignore before first run.

2. Target specific directories for large repos Full monorepo packs may exceed context windows. Pack src/ or specific packages.

3. Use XML format for LLM analysis XML format includes file metadata and is more parseable than markdown for LLMs.

Common Use Cases

Use Case 1: Codebase Documentation Generation

Scenario: Generate comprehensive documentation for undocumented repository.

Workflow:

1. npx repomix --include "src/**" --token-count — check size
2. npx repomix --include "src/**" — pack codebase
3. Feed XML output to Claude with prompt: “Generate comprehensive documentation”
4. Review and save to docs/ directory

Output: Full codebase documentation in one pass.

Use Case 2: Code Review for PR

Scenario: Review entire feature branch changes in context of full codebase.

Workflow:

1. Pack modified files: npx repomix --include "src/features/payments/**"
2. Include related files for context
3. Feed to LLM with specific review criteria
4. Get comprehensive review with cross-file analysis

Output: Detailed code review with architectural insights.

Troubleshooting

Issue: Output file too large for LLM context Solution: Use --include to scope to relevant directories. Check token count first.

Issue: Security check flags false positives Solution: Add patterns to .repomixignore. Example tokens in tests should be .env.example style.

Related Skills

• Scout - Fast codebase scouting
• Research - Technical research workflows
• MCP Builder - Build integrations for discovered APIs

Related Commands

• /ckm:repomix - Pack repository for analysis
• /ckm:scout - Quick codebase scouting