lint

A code-quality check for Python projects using Ruff, mypy, and Bandit. Ruff formats code and finds style problems, mypy checks types, and Bandit looks for common security issues.

In plain words
What is it for?
Run it before committing Python changes to format and lint source and tests, check type annotations, and scan the source for security issues.
Why use it?
It finds or fixes problems that could otherwise fail pre-commit checks or continuous integration, the automated checks that run for code changes.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/johnnichev/selectools/lint
Any agent
npx skills add johnnichev/selectools --skill lint
Clone the repo
git clone --depth 1 https://github.com/johnnichev/selectools

Made for: Claude Code, Codex.

Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 464 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00022 $0.00464
Opus 5 $0.00011 $0.00232
Sonnet 5 $0.00004 $0.00093
Haiku 4.5 $0.00002 $0.00046

Measured 2d ago against content hash 1f06f3b8e70e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

lint scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/lint/SKILL.md · 46 lines

What it actually says

Code Quality Pipeline

The repo migrated off black/isort/flake8 to ruff (format + lint) plus mypy and bandit. These are exactly what the pre-commit hooks and CI enforce, so matching them here keeps /release from tripping at commit time.

Mode

If "$ARGUMENTS" contains "check" or "check-only", run in check mode (no modifications). Otherwise, run in fix mode (auto-format and auto-fix, then verify).

Fix Mode (default)

Run these in sequence, stopping on first failure:

  1. ruff check src/ tests/ --fix (lint + autofix; replaces flake8 + isort)
  2. ruff format src/ tests/ (format; replaces black)
  3. mypy src/
  4. bandit -c pyproject.toml -r src/

Check Mode

Read-only, no modifications:

  1. ruff check src/ tests/
  2. ruff format src/ tests/ --check
  3. mypy src/
  4. bandit -c pyproject.toml -r src/

On Failure

  • ruff check failure: Report the violations with file paths and line numbers. Fix them — do not blanket-suppress with # noqa.
  • ruff format failure (check mode): Report which files need formatting. Offer to re-run in fix mode.
  • mypy failure: Report the type errors. Fix them — do not use # type: ignore unless truly unavoidable, and always give it an explicit error code (# type: ignore[code]) plus a comment explaining why.
  • bandit failure: Report the finding. Fix it, or justify with a scoped # nosec <ID> and a comment.

Success

When all four pass, report: "All clean — ruff check, ruff format, mypy, bandit passed."

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 46 lines · 22 tokens per session scan A 1f06f3b8e70e

Subscribe to this mod's changes

lint is a skill published in the GitHub repository johnnichev/selectools (11 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 22 tokens to every session and 464 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.