Cursor Rules - Enterprise Backend Engineering Suite

# Cursor Rules - Enterprise Backend Engineering Suite

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> A production-ready, extensible rule system for Cursor AI that transforms your coding assistant into a Senior Principal Backend Engineer with 20+ years of enterprise experience.

## 🎯 What is This?

This repository contains a comprehensive, language-agnostic rule system for [Cursor AI](https://cursor.sh/) that enforces:

- ✅ **Test-Driven Development (TDD)** workflows
- ✅ **Clean Architecture** and SOLID principles
- ✅ **Enterprise security** best practices
- ✅ **Production-grade** error handling and logging
- ✅ **CQRS** and Domain-Driven Design patterns
- ✅ **Multi-language support** (C#/.NET, Java/Spring Boot, and more)

## 🚀 Quick Start

### 1. Clone the Repository

```bash
git clone https://github.com/GoranErhartic/cursor-rules.git
cd cursor-rules
```

### 2. Install to Your Project

#### Option A: Automated Installation (Recommended)

**macOS / Linux:**

```bash
./install.sh /path/to/your/project
```

**Windows PowerShell:**

```powershell
.\install.ps1 -TargetPath "C:\Path\To\Your\Project"
```

The installer will:
- ✅ Automatically backup existing rules (if any)
- ✅ Copy all rules to your project
- ✅ Show clear success/error messages

#### Option B: Manual Installation

Copy the `.cursor` folder to the root of your project:

```bash
# macOS / Linux
cp -r .cursor /path/to/your/project/

# Windows PowerShell
Copy-Item -Path .cursor -Destination C:\Path\To\Your\Project\ -Recurse
```

### 3. Start Coding

Open your project in Cursor, and the AI will automatically:
- Act as a Senior Principal Backend Engineer
- Follow TDD workflows
- Apply language-specific best practices
- Enforce security and quality standards

## 📁 Structure

```
.cursor/rules/
├── patterns/                  # Language-agnostic patterns & concepts
│   ├── architecture.mdc       # Clean Architecture, CQRS, DDD, SOLID
│   ├── error-handling.mdc     # Result pattern, RFC 7807
│   ├── testing.mdc            # TDD workflow, AAA pattern
│   ├── security.mdc           # Security principles
│   ├── api-design.mdc         # REST conventions
│   ├── input-sanitization.mdc # Validation concepts
│   └── cqrs.mdc               # Command/Query separation
│
├── development/               # Development workflow
│   ├── tdd-planning.mdc       # Test planning requirements
│   └── code-implementation.mdc # Implementation workflow
│
└── languages/                 # Language-specific implementations
    ├── csharp/                # .NET / C# (14 files)
    ├── java/                  # Java / Spring Boot (14 files)
    └── _template/             # Template for adding new languages
        └── README.md          # Instructions for new languages
```

## 🌟 Key Features

### 🤖 AI Persona

The AI agent operates as a **Senior Principal Backend Engineer** with:
- 20+ years of enterprise experience
- Deep knowledge of distributed systems
- High-availability production environment expertise
- Strong emphasis on asking clarifying questions (never assumes!)

### 🧪 Test-Driven Development (TDD)

Enforces a strict TDD workflow:
1. **RED** - Write a failing test
2. **GREEN** - Minimal code to pass
3. **REFACTOR** - Clean up while keeping tests green

### 🏗️ Architecture Patterns

Built-in support for:
- **Vertical Slice Architecture** - Organize by feature, not layer
- **Clean Architecture** - Domain, Application, Infrastructure, API
- **CQRS** - Command/Query separation
- **Domain-Driven Design** - Aggregates, Value Objects, Domain Events

### 🛡️ Security First

Comprehensive security guidance:
- Input validation and sanitization
- SQL injection, XSS, and path traversal prevention
- Secrets management (no hardcoded credentials)
- HTTPS, CORS, and security headers
- JWT and OAuth2 patterns

### 📊 Code Quality

Enforces modern language features and best practices:
- C# 14 / .NET 10 idioms
- Java 21 features (records, sealed classes, pattern matching)
- Nullable reference types
- Async/await patterns
- Structured logging

## 🌍 Supported Languages

### C# / .NET

**14 comprehensive rule files** covering:

| Category | Files |
|----------|-------|
| **Core** | `code-quality`, `testing`, `error-handling`, `dependencies` |
| **Web** | `controllers`, `validation`, `input-sanitization` |
| **Data** | `ef-core` (Entity Framework Core) |
| **Infrastructure** | `logging` (Serilog), `resilience` (Polly), `messaging` (Rebus) |
| **Patterns** | `mediator` (CQRS), `auth` (JWT Bearer) |
| **Security** | `security`, `auth` |

**Technologies:**
- .NET 10, ASP.NET Core
- Entity Framework Core
- FluentValidation
- Serilog (structured logging)
- Polly (resilience patterns)
- Rebus (messaging)
-

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