Python quality gate

Run Python checks in order: Ruff lint, Ruff format, mypy, pytest, Bandit. Read repository instructions and configuration first; project commands and thresholds override defaults.

Detect

Find pyproject.toml, setup.py, setup.cfg, mypy.ini, and .python-version. Identify the Python target, tool settings, source directories (src/, app/, lib/, or root), and test discovery configuration.

Use the project environment. Check ruff --version, pytest --version, mypy --version, and bandit --version. Ruff and pytest are required; missing tools block execution (status 2). Mypy and Bandit are optional unless the project requires them. Report unavailable tools as skipped. Do not install tools or alter configuration for a check-only request; setup may require pip install ruff pytest pytest-cov.

Execute

Capture each command's output and exit status. Use configured paths; replace src below with the actual source path. Preserve stricter project settings rather than overriding them with defaults.

Order	Default command	Condition
1	ruff check . --output-format=grouped	Required
2	ruff format --check .	Required
3	mypy . --ignore-missing-imports --show-error-codes	If available; omit --ignore-missing-imports when it weakens project policy
4	pytest -v --tb=short --cov=src --cov-report=term-missing	Use coverage only when configured/requested and pytest-cov is installed
5	bandit -r src/ -ll --format=screen	If available

Run all available checks even after one fails; a test failure is a result, not a tool crash. Do not skip tests to get a pass. If there are no discovered tests, report that coverage gap; tests may live outside a tests/ directory.

Assess and report

Repository gates take precedence. Legacy default failure thresholds are Ruff F errors, test failures, high-severity Bandit issues, more than 10 mypy errors, and coverage below 80% when enabled. Always report each nonzero tool result separately; an aggregate threshold must not be described as every tool passing. Formatting failures and repository-required checks remain failures.

Prioritize syntax/undefined-name errors, failing tests, and security findings before style. ruff check . --statistics identifies counts and [*] fixable rules. Report overall result, per-tool status, actionable file:line diagnostics, coverage when measured, skipped checks, and suggested fixes. Preserve full logs rather than pasting every result. Write a full report when requested, including to --output {file} when supplied.

Fix and recover

When fixes are authorized, check first, run ruff check . --fix and ruff format ., inspect git diff, then rerun affected checks. Do not widen cleanup scope or change settings to hide failures.

• Wrong directory/no Python files: verify project root and configured source paths.
• Mypy cache corruption: confirm the project cache, remove .mypy_cache, and retry once. If it still fails, report an incomplete type check; do not call it passed.
• Missing required tool: report its name and setup command; do not continue as though the gate passed.

Reference loading table

Signal	Reference
Detailed rule severity, command options, output parsing	references/tool-commands.md
Full structured report requested	references/report-template.md
Tool configuration setup requested	references/pyproject-template.toml