| Design principles | KISS and YAGNI first, then DRY and SOLID, and how to weigh them |
| Design patterns | Factory, Singleton, Adapter, Strategy, and when each earns its place |
| Clean Architecture | Layers, dependency direction, ports and adapters |
| Domain modeling | Entities, value objects, aggregates, and where business rules live |
| Feature-first organization | Organizing by feature, sizing, boundaries, and shared code |
| Monolith or services | Modular monolith by default, and the reasons to split |
| Documenting architecture | C4 levels drawn in Mermaid, diagram rules, and where diagrams live |
| Deployment profiles | static, lean, enterprise |