@rulesgen/rulesgen

Analyze any codebase and auto-generate optimized AI coding assistant rules files.

Supports CLAUDE.md, .cursorrules, copilot-instructions.md, and .windsurfrules — all from a single command.

Install

npm install -g @rulesgen/rulesgen

Or run directly:

npx @rulesgen/rulesgen

Quick Start

# Set your Anthropic API key
export ANTHROPIC_API_KEY=sk-ant-...

# Generate rules for all tools
rulesgen generate

# Generate for specific tools only
rulesgen generate --tools claude,cursor

# Preview without writing files
rulesgen preview

# Update existing rules (merge mode)
rulesgen update

What It Does

1. Analyzes your codebase — detects frameworks, languages, dependencies, code patterns, project structure, and git history
2. Builds a tailored prompt — sends the analysis to Claude to generate project-specific rules
3. Writes optimized rules files — outputs files tuned for each AI coding tool

$ rulesgen generate --tools claude,cursor

  Analyzing project...

  Detected:
    Language    TypeScript (strict)
    Framework   Next.js 14, React 18, Tailwind CSS
    Database    PostgreSQL (Prisma)
    Testing     Vitest, React Testing Library
    Package Mgr pnpm

  Generating rules...

  ✓ CLAUDE.md          (1,247 tokens)
  ✓ .cursorrules       (892 tokens)

  Done in 8.2s

Commands

rulesgen generate [path]

Analyze a project and generate rules files. This is the default command.

| Flag | Description | Default | |------|-------------|---------| | --tools <list> | Comma-separated: claude, cursor, copilot, windsurf, all | all | | --output <dir> | Output directory | . | | --api-key <key> | Anthropic API key | $ANTHROPIC_API_KEY | | --model <model> | Claude model | claude-sonnet-4-5 | | --depth <level> | Analysis depth: quick, standard, deep | standard | | --focus <text> | Extra context to guide generation | — | | --force | Overwrite existing files without prompting | false | | --merge | Merge with existing rules files | false | | --preview | Print to stdout, don't write files | false | | --quiet | Suppress output except errors | false |

rulesgen update [path]

Re-analyze and merge updates into existing rules files. Same as generate --merge.

rulesgen preview [path]

Dry run — prints generated rules to stdout without writing any files.

rulesgen init

Create a .rulesgenrc.json config file in the current directory.

Configuration

Create a .rulesgenrc.json in your project root:

{
  "tools": ["claude", "cursor"],
  "depth": "standard",
  "focus": "This is a monorepo with shared packages",
  "ignore": ["node_modules", "dist", ".next"],
  "model": "claude-sonnet-4-5"
}

Also supports rulesgen.config.js, .rulesgenrc.yaml, and package.json "rulesgen" field via cosmiconfig.

Supported Languages & Frameworks

| Language | Detected From | |----------|---------------| | JavaScript/TypeScript | package.json — React, Next.js, Vue, Nuxt, Angular, Svelte, NestJS, Express, Fastify, Vite, Tailwind, Prisma, and 50+ more | | Go | go.mod — Gin, Echo, Fiber, GORM, sqlx, and more | | Python | requirements.txt, pyproject.toml — Django, FastAPI, Flask, SQLAlchemy, pytest, and more |

Also detects: Docker, Terraform, CDK, GitHub Actions, monorepo tools (Nx, Turborepo, Lerna).

Analysis Depth

| Level | What it analyzes | |-------|-----------------| | quick | Project structure, dependencies, frameworks | | standard | + code patterns (naming, imports, async style, tests) | | deep | + git history (recent commits, contributors, recently modified files) |

API Key

The API key is resolved in order:

1. --api-key flag
2. ANTHROPIC_API_KEY environment variable
3. ~/.rulesgen/config.json

Output Files

| Tool | File | Location | |------|------|----------| | Claude Code | CLAUDE.md | Project root | | Cursor | .cursorrules | Project root | | GitHub Copilot | copilot-instructions.md | .github/ | | Windsurf | .windsurfrules | Project root |

License

MIT