Clean Architecture

When you're designing a new system or refactoring toward better separation of concerns, this gives you 42 prioritized rules from Uncle Bob's Clean Architecture book. It's organized into eight categories from critical dependency direction rules to testing concerns, each with a clear impact level. The structure is helpful: you can jump straight to the six critical dependency rules when reviewing if your business logic is leaking framework imports, or check the use case isolation section when orchestration starts mixing with presentation. Think of it as a structured checklist that keeps you honest about where boundaries should exist and whether you're actually respecting them in practice.