python-style

Create a uv project with pyproject.toml, a committed uv.lock, and a src/<package>/ layout, then package it with ix.buildUvApplication. For tiny single-file scripts without PyPI dependencies, use ix.writePythonApplication instead.

Zuban is the default, running zuban check --strict including disallow-untyped-defs. Set pyChecker to "ty" for the older gradual checker or "mypy" only for a deliberate reason, and disable checking with check = false only when justified.

Parse external JSON into a pydantic model at the boundary instead of casting or threading dict[str, Any] through the code. The model validates the shape once with path-precise errors, and every downstream access is typed.

The ruff ANN401 rule bans bare typing.Any in annotations everywhere, and TID251 bans typing.cast because a wrong cast is a latent bug no checker can catch. Use pydantic models for untrusted data or explicit local annotations for known stdlib return types.

Opt out per line with an annotated noqa comment in the form # noqa: <rule> -- <reason>, never a blanket silence. The rare unavoidable cast opts out per file with # noqa: TID251 plus a one-line reason.