Instruction file imported from enorm-labs/event-junkie (.github/instructions/python.instructions.md). Copyright stays with the author.

Python

The scripts under scripts/, deploy/alerts/ and deploy/dashboards/, and nothing else. Not a Python project: no pyproject.toml, no venv, no test runner. scripts/README.md § The short version carries the decisions; this is what they mean when you edit a .py file.

• Standard library only, with argparse. ste_lint.py and everything under deploy/ are copied to a node and run under the python3 there, where nothing is installed. outline_text.py is the one exception, and its wrapper builds the venv it needs. A CLI library (click, typer) is the same decision as a shell framework, and scripts/README.md records both as decided against.
• ruff check and ruff format, from the root ruff.toml: line length 120, target-version = "py312" (the python3 on an Ubuntu 24.04 node), rules E, F, W, B, I. The pin is RUFF_VERSION in validate-python.yml; the commit hook uses the ruff on $PATH (brew install ruff), the way ShellCheck does. Without one, uvx ruff@<RUFF_VERSION> runs the pinned release. Not selected on purpose: UP031, because %-formatting is deliberate in code that runs under whatever python3 a node has, and PLW1510, because every subprocess.run here reads its own returncode.
• Tests are plain scripts, not pytest. deploy/alerts/test_diff_alerts.py and deploy/dashboards/test_lint_dashboard.py count checks and exit non-zero; validate-python.yml runs both. Two files do not justify a runner. A third test follows the same shape, and goes into that workflow.
• Importing a sibling from a test: sys.path.insert(0, str(pathlib.Path(__file__).resolve().parent)), then the import with # noqa: E402. The files are run, not imported, so there is no package to make and no __init__.py.
• --help before anything else. Every script under scripts/ answers -h or --help with exit 0 before it touches a tool, a file or the network, and scripts/index-parity.sh asserts it. argparse gives that for free as long as nothing runs at import time.