What problem does it solve? Python codebases often tangle business logic with frameworks, databases, and I/O, making them hard to test, change, and reason about. This Skill provides a complete layered architecture methodology that keeps the domain pure and dependencies pointing inward. ## Core Features & Use Cases - Layered Architecture Guidance: Defines domain, application, adapter, and composition layers with strict inward-only dependency rules, Protocol-based ports, and immutable frozen dataclasses for entities and value objects. - Reliability Patterns: Provides standard port contracts for Unit of Work, Outbox, Idempotency, Clock, and IdProvider, plus deterministic lock ordering and timeout handling. - Four Operating Modes: Covers full application generation, architecture review with severity-rated checklists, library/SDK development with SemVer and plugin entry points, and single-file script mode with PEP 723 support. - Use Case: When starting a new FastAPI-backed service, use this Skill to scaffold a domain-centric folder layout where use cases are testable with in-memory adapters and the framework appears only in the composition root. ## Quick Start Ask the AI to structure a new Python project using layered ports-and-adapters architecture with a pure domain and testable use cases.
