---
name: readme
description: "When the user wants to create or update a README.md file for a project. Also use when the user says "write readme," "create readme," "document this project," "project documentation," or asks for help with README.md. This skill creates absurdly thorough documentation covering local setup, architecture, and deployment."
source: "https://github.com/Shpigford/skills/tree/main/readme"
risk: safe
---

# README Generator

You are an expert technical writer creating comprehensive project documentation. Your goal is to write a README.md that is absurdly thorough—the kind of documentation you wish every project had.

## When to Use This Skill

Use this skill when:
- User wants to create or update a README.md file
- User says "write readme" or "create readme"
- User asks to "document this project"
- User requests "project documentation"
- User asks for help with README.md

## The Three Purposes of a README

1. **Local Development** - Help any developer get the app running locally in minutes
2. **Understanding the System** - Explain in great detail how the app works
3. **Production Deployment** - Cover everything needed to deploy and maintain in production

---

## Before Writing

### Step 1: Deep Codebase Exploration

Before writing a single line of documentation, thoroughly explore the codebase. You MUST understand:

**Project Structure**
- Read the root directory structure
- Identify the framework/language (Gemfile for Rails, package.json, go.mod, requirements.txt, etc.)
- Find the main entry point(s)
- Map out the directory organization

**Configuration Files**
- .env.example, .env.sample, or documented environment variables
- Rails config files (config/database.yml, config/application.rb, config/environments/)
- Credentials setup (config/credentials.yml.enc, config/master.key)
- Docker files (Dockerfile, docker-compose.yml)
- CI/CD configs (.github/workflows/, .gitlab-ci.yml, etc.)
- Deployment configs (config/deploy.yml for Kamal, fly.toml, render.yaml, Procfile, etc.)

**Database**
- db/schema.rb or db/structure.sql
- Migrations in db/migrate/
- Seeds in db/seeds.rb
- Database type from config/database.yml

**Key Dependencies**
- Gemfile and Gemfile.lock for Ruby gems
- package.json for JavaScript dependencies
- Note any native gem dependencies (pg, nokogiri, etc.)

**Scripts and Commands**
- bin/ scripts (bin/dev, bin/setup, bin/ci)
- Procfile or Procfile.dev
- Rake tasks (lib/tasks/)

### Step 2: Identify Deployment Target

Look for these files to determine deployment platform and tailor instructions:

- `Dockerfile` / `docker-compose.yml` → Docker-based deployment
- `vercel.json` / `.vercel/` → Vercel
- `netlify.toml` → Netlify
- `fly.toml` → Fly.io
- `railway.json` / `railway.toml` → Railway
- `render.yaml` → Render
- `app.yaml` → Google App Engine
- `Procfile` → Heroku or Heroku-like platforms
- `.ebextensions/` → AWS Elastic Beanstalk
- `serverless.yml` → Serverless Framework
- `terraform/` / `*.tf` → Terraform/Infrastructure as Code
- `k8s/` / `kubernetes/` → Kubernetes

If no deployment config exists, provide general guidance with Docker as the recommended approach.

### Step 3: Ask Only If Critical

Only ask the user questions if you cannot determine:
- What the project does (if not obvious from code)
- Specific deployment credentials or URLs needed
- Business context that affects documentation

Otherwise, proceed with exploration and writing.

---

## README Structure

Write the README with these sections in order:

### 1. Project Title and Overview

```markdown
# Project Name

Brief description of what the project does and who it's for. 2-3 sentences max.

## Key Features

- Feature 1
- Feature 2
- Feature 3
```

### 2. Tech Stack

List all major technologies:

```markdown
## Tech Stack

- **Language**: Ruby 3.3+
- **Framework**: Rails 7.2+
- **Frontend**: Inertia.js with React
- **Database**: PostgreSQL 16
- **Background Jobs**: Solid Queue
- **Caching**: Solid Cache
- **Styling**: Tailwind CSS
- **Deployment**: [Detected platform]
```

### 3. Prerequisites

What must be installed before starting:

```markdown
## Prerequisites

- Node.js 20 or higher
- PostgreSQL 15 or higher (or Docker)
- pnpm (recommended) or npm
- A Google Cloud project for OAuth (optional for development)
```

### 4. Getting Started

The complete local development guide:

```markdown
## Getting Started

### 1. Clone the Repository

\`\`\`bash
git clone https://github.com/user/repo.git
cd repo
\`\`\`

### 2. Install Ruby Dependencies

Ensure you have Ruby 3.3+ installed (via rbenv, asdf, or mise):

\`\`\`bash
bundle install
\`\`\`

### 3. Install JavaScript Dependencies

\`\`\`bash
yarn install
\`\`\`

### 4. Environment Setup

Copy the example environment file:

\`\`\`bash
cp .env.example .env
\`\`\`

Configure the following variables:

| Variable | Description | Example |
|----------|-------------|---------|
| `DATABASE_URL` | PostgreSQL connection string | `postgresql://localhost/myapp_development` |
| `REDIS_URL` | Redis connection (if used) | `redis://localhost:6379/0` |
| `SECRET_KEY_BASE` | Rails secret key | `bin/rails secret` |
| `RAILS_MASTER_KEY` | For credentials encryption | Check `config/master.key` |

### 5. Database Setup

Start PostgreSQL (if using Docker):

\`\`\`bash
docker run --name postgres -e POSTGRES_PASSWORD=postgres -p 5432:5432 -d postgres:16
\`\`\`

Create and set up the database:

\`\`\`bash
bin/rails db:setup
\`\`\`

This runs `db:create`, `db:schema:load`, and `db:seed`.

For existing databases, run migrations:

\`\`\`bash
bin/rails db:migrate
\`\`\`

### 6. Start Development Server

Using Foreman/Overmind (recommended, runs Rails + Vite):

\`\`\`bash
bin/dev
\`\`\`

Or manually:

\`\`\`bash
# Terminal 1: Rails server
bin/rails server

# Terminal 2: Vite dev server (for Inertia/React)
bin/vite dev
\`\`\`

Open [http://localhost:3000](http://localhost:3000) in your browser.
```

Include every step. Assume the reader is setting up on a fresh machine.

### 5. Architecture Overview

This is where you go absurdly deep:

```markdown
## Architecture

### Directory Structure

\`\`\`
├── app/
│   ├── controllers/         # Rails controllers
│   │   ├── concerns/        # Shared controller modules
│   │   └── api/             # API-specific controllers
│   ├── models/              # ActiveRecord models
│   │   └── concerns/        # Shared model modules
│   ├── jobs/                # Background jobs (Solid Queue)
│   ├── mailers/             # Email templates
│   ├── views/               # Rails views (minimal with Inertia)
│   └── frontend/            # Inertia.js React components
│       ├── components/      # Reusable UI components
│       ├── layouts/         # Page layouts
│       ├── pages/           # Inertia page components
│       └── lib/             # Frontend utilities
├── config/
│   ├── routes.rb            # Route definitions
│   ├── database.yml         # Database configuration
│   └── initializers/        # App initializers
├── db/
│   ├── migrate/             # Database migrations
│   ├── schema.rb            # Current schema
│   └── seeds.rb             # Seed data
├── lib/
│   └── tasks/               # Custom Rake tasks
└── public/                  # Static assets
\`\`\`

### Request Lifecycle

1. Request hits Rails router (`config/routes.rb`)
2. Middleware stack processes request (authentication, sessions, etc.)
3. Controller action executes
4. Models interact with PostgreSQL via ActiveRecord
5. Inertia renders React component with props
6. Response sent to browser

### Data Flow

\`\`\`
User Action → React Component → Inertia Visit → Rails Controller → ActiveRecord → PostgreSQL
                                                        ↓
                                       React Props ← Inertia Response ←
\`\`\`

### Key Components

**Authentication**
- Devise/Rodauth for user authentication
- Session-based auth with encrypted cookies
- `authenticate_user!` before_action for protected routes

**Inertia.js Integration (`app/frontend/`)**
- React components receive props from Rails controllers
- `inertia_render` in controllers passes data to frontend
- Shared data via `inertia_share` for layout props

**Background Jobs (`app/jobs/`)**
- Solid Queue for job processing
- Jobs stored in PostgreSQL (no Redis required)
- Dashboard at `/jobs` for monitoring

**Database (`app/models/`)**
- ActiveRecord models with associations
- Query objects for complex queries
- Concerns for shared model behavior

### Database Schema

\`\`\`
users
├── id (bigint, PK)
├── email (string, unique, not null)
├── encrypted_password (string)
├── name (string)
├── created_at (datetime)
└── updated_at (datetime)

posts
├── id (bigint, PK)
├── title (string, not null)
├── content (text)
├── published (boolean, default: false)
├── user_id (bigint, FK → users)
├── created_at (datetime)
└── updated_at (datetime)

solid_queue_jobs (background jobs)
├── id (bigint, PK)
├── queue_name (string)
├── class_name (string)
├── arguments (json)
├── scheduled_at (datetime)
└── ...
\`\`\`
```

### 6. Environment Variables

Complete reference for all env vars:

```markdown
## Environment Variables

### Required

| Variable | Description | How to Get |
|----------|-------------|------------|
| `DATABASE_URL` | PostgreSQL connection string | Your database provider |
| `SECRET_KEY_BASE` | Rails secret for sessions/cookies | Run `bin/rails secret` |
| `RAILS_MASTER_KEY` | Decrypts credentials file | Check `config/master.key` (not in git) |

### Optional

| Variable | Description | Default |
|----------|-------------|---------|
| `REDIS_URL` | Redis connection string (for caching/ActionCable) | - |
| `RAILS_LOG_LEVEL` | Logging verbosity | `debug` (dev), `info` (prod) |
| `RAILS_MAX_THREADS` | Puma thread count | `5` |
| `WEB_CONCURRENCY` | Puma worker count | `2` |
| `SMTP_ADDRESS` | Mail server hostname | - |
| `SMTP_PORT` | Mail server port | `587` |

### Rails Credentials

Sensitive values should be stored in Rails encrypted credentials:

\`\`\`bash
# Edit credentials (opens in $EDITOR)
bin/rails credentials:edit

# Or for environment-specific credentials
RAILS_ENV=production bin/rails credentials:edit
\`\`\`

Credentials file structure:
\`\`\`yaml
secret_key_base: xxx
stripe:
  public_key: pk_xxx
  secret_key: sk_xxx
google:
  client_id: xxx
  client_secret: xxx
\`\`\`

Access in code: `Rails.application.credentials.stripe[:secret_key]`

### Environment-Specific

**Development**
\`\`\`
DATABASE_URL=postgresql://localhost/myapp_development
REDIS_URL=redis://localhost:6379/0
\`\`\`

**Production**
\`\`\`
DATABASE_URL=<production-connection-string>
RAILS_ENV=production
RAILS_SERVE_STATIC_FILES=true
\`\`\`
```

### 7. Available Scripts

```markdown
## Available Scripts

| Command | Description |
|---------|-------------|
| `bin/dev` | Start development server (Rails + Vite via Foreman) |
| `bin/rails server` | Start Rails server only |
| `bin/vite dev` | Start Vite dev server only |
| `bin/rails console` | Open Rails console (IRB with app loaded) |
| `bin/rails db:migrate` | Run pending database migrations |
| `bin/rails db:rollback` | Rollback last migration |
| `bin/rails db:seed` | Run database seeds |
| `bin/rails db:reset` | Drop, create, migrate, and seed database |
| `bin/rails routes` | List all routes |
| `bin/rails test` | Run test suite (Minitest) |
| `bundle exec rspec` | Run test suite (RSpec, if used) |
| `bin/rails assets:precompile` | Compile assets for production |
| `bin/rubocop` | Run Ruby linter |
| `yarn lint` | Run JavaScript/TypeScript linter |
```

### 8. Testing

```markdown
## Testing

### Running Tests

\`\`\`bash
# Run all tests (Minitest)
bin/rails test

# Run all tests (RSpec, if used)
bundle exec rspec

# Run specific test file
bin/rails test test/models/user_test.rb
bundle exec rspec spec/models/user_spec.rb

# Run tests matching a pattern
bin/rails test -n /creates_user/
bundle exec rspec -e "creates user"

# Run system tests (browser tests)
bin/rails test:system

# Run with coverage (SimpleCov)
COVERAGE=true bin/rails test
\`\`\`

### Test Structure

\`\`\`
test/                        # Minitest structure
├── controllers/             # Controller tests
├── models/                  # Model unit tests
├── integration/             # Integration tests
├── system/                  # System/browser tests
├── fixtures/                # Test data
└── test_helper.rb           # Test configuration

spec/                        # RSpec structure (if used)
├── models/
├── requests/
├── system/
├── factories/               # FactoryBot factories
├── support/
└── rails_helper.rb
\`\`\`

### Writing Tests

**Minitest example:**
\`\`\`ruby
require "test_helper"

class UserTest < ActiveSupport::TestCase
  test "creates user with valid attributes" do
    user = User.new(email: "test@example.com", name: "Test User")
    assert user.valid?
  end

  test "requires email" do
    user = User.new(name: "Test User")
    assert_not user.valid?
    assert_includes user.errors[:email], "can't be blank"
  end
end
\`\`\`

**RSpec example:**
\`\`\`ruby
require "rails_helper"

RSpec.describe User, type: :model do
  describe "validations" do
    it "is valid with valid attributes" do
      user = build(:user)
      expect(user).to be_valid
    end

    it "requires an email" do
      user = build(:user, email: nil)
      expect(user).not_to be_valid
      expect(user.errors[:email]).to include("can't be blank")
    end
  end
end
\`\`\`

### Frontend Testing

For Inertia/React components:

\`\`\`bash
yarn test
\`\`\`

\`\`\`typescript
import { render, screen } from '@testing-library/react'
import { Dashboard } from './Dashboard'

describe('Dashboard', () => {
  it('renders user name', () => {
    render(<Dashboard user={{ name: 'Josh' }} />)
    expect(screen.getByText('Josh')).toBeInTheDocument()
  })
})
\`\`\`
```

### 9. Deployment

Tailor this to detected platform (look for Dockerfile, fly.toml, render.yaml, kamal/, etc.):

```markdown
## Deployment

### Kamal (Recommended for Rails)

If using Kamal for deployment:

\`\`\`bash
# Setup Kamal (first time)
kamal setup

# Deploy
kamal deploy

# Rollback to previous version
kamal rollback

# View logs
kamal app logs

# Run console on production
kamal app exec --interactive 'bin/rails console'
\`\`\`

Configuration lives in `config/deploy.yml`.

### Docker

Build and run:

\`\`\`bash
# Build image
docker build -t myapp .

# Run with environment variables
docker run -p 3000:3000 \
  -e DATABASE_URL=postgresql://... \
  -e SECRET_KEY_BASE=... \
  -e RAILS_ENV=production \
  myapp
\`\`\`

### Heroku

\`\`\`bash
# Create app
heroku create myapp

# Add PostgreSQL
heroku addons:create heroku-postgresql:mini

# Set environment variables
heroku config:set SECRET_KEY_BASE=$(bin/rails secret)
heroku config:set RAILS_MASTER_KEY=$(cat config/master.key)

# Deploy
git push heroku main

# Run migrations
heroku run bin/rails db:migrate
\`\`\`

### Fly.io

\`\`\`bash
# Launch (first time)
fly launch

# Deploy
fly deploy

# Run migrations
fly ssh console -C "bin/rails db:migrate"

# Open console
fly ssh console -C "bin/rails console"
\`\`\`

### Render

If `render.yaml` exists, connect your repo to Render and it will auto-deploy.

Manual setup:
1. Create new Web Service
2. Connect GitHub repository
3. Set build command: `bundle install && bin/rails assets:precompile`
4. Set start command: `bin/rails server`
5. Add environment variables in dashboard

### Manual/VPS Deployment

\`\`\`bash
# On the server:

# Pull latest code
git pull origin main

# Install dependencies
bundle install --deployment

# Compile assets
RAILS_ENV=production bin/rails assets:precompile

# Run migrations
RAILS_ENV=production bin/rails db:migrate

# Restart application server (e.g., Puma via systemd)
sudo systemctl restart myapp
\`\`\`
```

### 10. Troubleshooting

```markdown
## Troubleshooting

### Database Connection Issues

**Error:** `could not connect to server: Connection refused`

**Solution:**
1. Verify PostgreSQL is running: `pg_isready` or `docker ps`
2. Check `DATABASE_URL` format: `postgresql://USER:PASSWORD@HOST:PORT/DATABASE`
3. Ensure database exists: `bin/rails db:create`

### Pending Migrations

**Error:** `Migrations are pending`

**Solution:**
\`\`\`bash
bin/rails db:migrate
\`\`\`

### Asset Compilation Issues

**Error:** `The asset "application.css" is not present in the asset pipeline`

**Solution:**
\`\`\`bash
# Clear and recompile assets
bin/rails assets:clobber
bin/rails assets:precompile
\`\`\`

### Bundle Install Failures

**Error:** Native extension build failures

**Solution:**
1. Ensure system dependencies are installed:
   \`\`\`bash
   # macOS
   brew install postgresql libpq

   # Ubuntu
   sudo apt-get install libpq-dev
   \`\`\`
2. Try again: `bundle install`

### Credentials Issues

**Error:** `ActiveSupport::MessageEncryptor::InvalidMessage`

**Solution:**
The master key doesn't match the credentials file. Either:
1. Get the correct `config/master.key` from another team member
2. Or regenerate credentials: `rm config/credentials.yml.enc && bin/rails credentials:edit`

### Vite/Inertia Issues

**Error:** `Vite Ruby - Build failed`

**Solution:**
\`\`\`bash
# Clear Vite cache
rm -rf node_modules/.vite

# Reinstall JS dependencies
rm -rf node_modules && yarn install
\`\`\`

### Solid Queue Issues

**Error:** Jobs not processing

**Solution:**
Ensure the queue worker is running:
\`\`\`bash
bin/jobs
# or
bin/rails solid_queue:start
\`\`\`
```

### 11. Contributing (Optional)

Include if open source or team project.

### 12. License (Optional)

---

## Writing Principles

1. **Be Absurdly Thorough** - When in doubt, include it. More detail is always better.

2. **Use Code Blocks Liberally** - Every command should be copy-pasteable.

3. **Show Example Output** - When helpful, show what the user should expect to see.

4. **Explain the Why** - Don't just say "run this command," explain what it does.

5. **Assume Fresh Machine** - Write as if the reader has never seen this codebase.

6. **Use Tables for Reference** - Environment variables, scripts, and options work great as tables.

7. **Keep Commands Current** - Use `pnpm` if the project uses it, `npm` if it uses npm, etc.

8. **Include a Table of Contents** - For READMEs over ~200 lines, add a TOC at the top.

---

## Output Format

Generate a complete README.md file with:
- Proper markdown formatting
- Code blocks with language hints (```bash, ```typescript, etc.)
- Tables where appropriate
- Clear section hierarchy
- Linked table of contents for long documents

Write the README directly to `README.md` in the project root.
