coding-python-clean-architecturelisted

# Layered Architecture for Python ## Overview Framework-agnostic, typed Python architecture optimized for **change**, **testability**, and **clear boundaries**. Inner layers never import from outer layers. Domain stays pure. **Primary goal:** Keep the cost of change low over the lifetime of the system. Business logic should be easy to understand, test, and evolve independently of infrastructure choices. **Target:** Python >=3.10 | Typed | Pure domain | Framework-agnostic core | No compatibility shims ## When to Use - Starting a new Python project that needs long-term maintainability - Reviewing existing code for architecture violations (imports crossing layers) - Deciding where a new class/function belongs (domain vs application vs adapter) - Structuring data flow between external inputs, domain logic, and outputs - Setting up testing strategy with proper isolation - Implementing reliability patterns (UoW, outbox, idempotency) - Refactoring framework-centric code to layered architecture **When NOT to use:** - Projects already using a different established architecture **Single-file scripts and throwaway prototypes stay in this skill** - they route to SCRIPT mode (see `script-mode.md` and the mode-selection table below), one of this skill's four operating modes. Do not drop the skill for them. **Capability check (REVIEW / judgment).** Spotting architecture/layer violations and the true-vs-accidental-duplication call is capability-sensitive - a weaker model misjudges i