PyPI Package Scaffold

"A library is only as good as its documentation and its tests. Semantic versioning is a contract with your users — break it and you break trust."

Core Philosophy

A Python package is a contract with its users in three parts: the API surface (what's public), the version (what changes are breaking), and the metadata (who maintains it, license, supported Python versions). Packaging is not an afterthought — a package that cannot be installed reliably, has no tests, ships without type stubs, or lacks documentation is not ready for PyPI. The scaffold establishes all of these before the first publish, using the src/ layout and Trusted Publishing.

Non-Negotiable Constraints:

1. NO PUBLISH WITHOUT TESTS — pytest must pass (the publish job needs: test) before any upload.
2. SEMVER IS LAW — breaking changes require a major version bump; no exceptions.
3. METADATA REQUIRED — name, version, description, license, authors, readme, requires-python, classifiers.
4. MULTI-VERSION SUPPORT — requires-python = ">=3.10" minimum; test matrix covers 3.10–3.14.
5. DETERMINISTIC BUILDS — pinned build dependencies; PYTHONHASHSEED=0 in CI; ship both sdist and wheel.

Full principle table, KB lookups, command sequences, anti-patterns, discipline rules, and error recovery live in references/conventions.md.

Workflow

SCAFFOLD   Create the src-layout structure:
             src/<package>/{__init__.py (+__all__), py.typed, _internal/}
             tests/  docs/  pyproject.toml  README.md  LICENSE  CHANGELOG.md
             .github/workflows/{ci.yml, publish.yml}
           (Full pyproject.toml in references/pyproject-template.md.)

CONFIGURE  Set all required metadata + classifiers + [project.urls] (checklist in conventions.md).

TEST       pip install -e ".[dev]"; pytest --cov; mypy --strict; ruff check + format --check.

BUILD      python -m build; twine check dist/*; inspect wheel contents.

PUBLISH    TestPyPI first (upload + install-verify), then PyPI. Use Trusted Publishing (OIDC), no tokens.
           (Automated workflow in references/ci-publish-workflow.md.)

Exit criteria: required metadata complete; pytest, mypy --strict, ruff, and twine check dist/* all pass; sdist + wheel built; TestPyPI install verified; publish workflow gated on the test matrix via needs: test.

State Block

<pypi-package-state>
phase: SCAFFOLD | CONFIGURE | TEST | BUILD | PUBLISH | COMPLETE
package_name: [name]
version: [semver]
python_requires: [version]
build_tool: hatchling | flit | setuptools | build
type_stubs: true | false
ci_configured: true | false
testpypi_published: true | false
pypi_published: true | false
last_action: [description]
next_action: [description]
</pypi-package-state>

Output Template

• Package scaffold checklist — references/output-templates.md.
• Complete pyproject.toml (metadata, tool config, build-system) — references/pyproject-template.md.
• GitHub Actions test matrix + Trusted-Publishing workflow — references/ci-publish-workflow.md.
• Principle table, KB lookups, command sequences, anti-patterns, discipline rules, error recovery — references/conventions.md.

Integration with Other Skills