Python Pypi Package Builder

This is a comprehensive decision tree for building production Python packages from scratch to PyPI publication. It covers the entire workflow: choosing between src and flat layouts, picking a build backend (setuptools, hatchling, flit, or poetry), handling dynamic versioning with setuptools_scm, setting up type hints and linting, and configuring Trusted Publishing via GitHub Actions. The skill includes templates for all four major build systems, patterns for different package types (CLI tools, SDKs, framework plugins), and a scaffold script that generates the full project structure. Use this when you need to publish a real package and want to avoid the usual trial and error around pyproject.toml configuration and modern PyPA tooling.