Python Packaging

You are a Python packaging specialist. The user wants to package a Python library for PyPI distribution with proper metadata, dependencies, and build configuration.

What to check first

• Run python --version to ensure Python 3.7+ is installed
• Verify build and twine are installed: pip install build twine
• Check that your project has a src/ or top-level package directory with __init__.py files
• Confirm you have a README.md and LICENSE file in the project root

Steps

1. Create a pyproject.toml file in your project root with [build-system], [project], and [tool.setuptools] sections defining name, version, description, authors, and dependencies
2. Add version = "0.1.0" and description = "Your package description" to the [project] table in pyproject.toml
3. List all runtime dependencies in dependencies = [...] array and optional dev dependencies in [project.optional-dependencies]
4. Define package discovery using [tool.setuptools.packages] with find = {} or explicitly list packages with packages = ["your_package"]
5. Add readme = "README.md", requires-python = ">=3.7", and license = {text = "MIT"} to [project] section
6. Optional: Create a src/ layout and configure [tool.setuptools] with package-dir = {"" = "src"} for better separation
7. Run python -m build to generate distribution files (.whl and .tar.gz) in the dist/ directory
8. Validate your package with twine check dist/* before uploading
9. For PyPI upload, run twine upload dist/* or twine upload --repository testpypi dist/* for test environment

Code

# pyproject.toml — complete minimal example for PyPI distribution

[build-system]
requires = ["setuptools>=65.0", "wheel"]
build-backend = "setuptools.build_meta"

[project]
name = "my-awesome-package"
version = "0.1.0"
description = "A brief description of your package"
readme = "README.md"
requires-python = ">=3.7"
license = {text = "MIT"}
authors = [
    {name = "Your Name", email = "your.email@example.com"}
]
keywords = ["python", "packaging", "pypi"]
classifiers = [
    "Development Status :: 3 - Alpha",
    "Intended Audience :: Developers",
    "License :: OSI Approved :: MIT License",
    "Programming Language :: Python :: 3",
    "Programming Language :: Python :: 3.7",
    "Programming Language :: Python :: 3.8",
    "Programming Language :: Python :: 3.9",
]
dependencies = [
    "requests

Note: this example was truncated in the source. See the GitHub repo for the latest full version.

Common Pitfalls

• Treating this skill as a one-shot solution — most workflows need iteration and verification
• Skipping the verification steps — you don't know it worked until you measure
• Applying this skill without understanding the underlying problem — read the related docs first

When NOT to Use This Skill

• When a simpler manual approach would take less than 10 minutes
• On critical production systems without testing in staging first
• When you don't have permission or authorization to make these changes

How to Verify It Worked

• Run the verification steps documented above
• Compare the output against your expected baseline
• Check logs for any warnings or errors — silent failures are the worst kind

Production Considerations

• Test in staging before deploying to production
• Have a rollback plan — every change should be reversible
• Monitor the affected systems for at least 24 hours after the change