Python Packaging

---
triggers:
  - "python packaging"
name: python-packaging
description: Create distributable Python packages with proper project structure, setup.py/pyproject.toml, and publishing to PyPI. Use when packaging Python libraries, creating CLI tools, or distributing Python code.
---

# Python Packaging

Comprehensive guide to creating, structuring, and distributing Python packages using modern packaging tools, pyproject.toml, and publishing to PyPI.

## When to Use This Skill

- Creating Python libraries for distribution
- Building command-line tools with entry points
- Publishing packages to PyPI or private repositories
- Setting up Python project structure
- Creating installable packages with dependencies
- Building wheels and source distributions
- Versioning and releasing Python packages
- Creating namespace packages
- Implementing package metadata and classifiers

## Core Concepts

### 1. Package Structure
- **Source layout**: `src/package_name/` (recommended)
- **Flat layout**: `package_name/` (simpler but less flexible)
- **Package metadata**: pyproject.toml, setup.py, or setup.cfg
- **Distribution formats**: wheel (.whl) and source distribution (.tar.gz)

### 2. Modern Packaging Standards
- **PEP 517/518**: Build system requirements
- **PEP 621**: Metadata in pyproject.toml
- **PEP 660**: Editable installs
- **pyproject.toml**: Single source of configuration

### 3. Build Backends
- **setuptools**: Traditional, widely used
- **hatchling**: Modern, opinionated
- **flit**: Lightweight, for pure Python
- **poetry**: Dependency management + packaging

### 4. Distribution
- **PyPI**: Python Package Index (public)
- **TestPyPI**: Testing before production

## Note
Skill content truncated for token efficiency. Full version available in the source repository.