Iron Law

USE SOURCE LAYOUT (src/) FOR ALL SERVICES AND INSTALLABLE TOOLS — flat layout works for scripts but causes import confusion in larger projects and CI environments

Python Packaging

Project structure patterns for Python 3.14 services, internal tools, and CLI applications.

Scope

This skill covers the workspace-relevant subset of Python packaging:

• pyproject.toml structure for FastAPI services and internal tools
• Source layout vs flat layout decision
• CLI entry points (Click, argparse) for internal tooling
• Dynamic versioning
• Editable installs for development

Out of scope for this workspace: PyPI publishing, wheels, namespace packages, C extensions, private package index. The workspace builds services and internal tools, not distributable libraries.