Detector: Lint Runner

Detector: Lint Runner

Wraps the ruff linter for Python code quality checks.

Property	Value
Name	lint-runner
Tier	DETERMINISTIC
Languages	Python
External tool	ruff
LLM required	No
Confidence	1.00

What it detects

Python lint violations via ruff — pyflakes errors, style issues, import sorting, bandit security checks, bugbear patterns, and more.

How it works

1. Runs ruff check --output-format=json --no-fix on the repo
2. Parses the JSON violations array
3. Maps rule code prefixes to Sentinel severity levels

Severity mapping

Ruff prefix	Category	Sentinel severity
F	Pyflakes	HIGH
S	Bandit (security)	HIGH
E	Errors	MEDIUM
B	Bugbear	MEDIUM
W	Warnings	LOW
I	isort	LOW
C	Convention	LOW

Example finding

[LINT] src/example/utils.py:23 — F841 (unused-variable)
  Local variable `result` is assigned but never used
  Severity: HIGH, Confidence: 1.00

Prerequisites

pip install ruff
# Or: pip install sentinel[detectors]

Known limitations

• Most useful for repos without existing CI lint checks — if ruff already runs in CI, these findings are redundant
• 60-second timeout
• Excludes the .sentinel directory