ruff-linting

A project rule for using Ruff, a tool that checks Python code for style and common errors. It also defines how to fix reported issues and document necessary exceptions.

In plain words
What is it for?
Use it when Ruff reports problems or when someone asks to fix lint errors, including applying fixes repeatedly and adding specific justifications for valid ignores.
Why use it?
It gives the project a consistent way to find and correct Python lint errors instead of handling them differently each time.

Cursor rule for Cursor

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 rules/technickai/ai-coding-config/ruff-linting
Clone the repo
git clone --depth 1 https://github.com/TechNickAI/ai-coding-config

Made for: Cursor.

Per session 4 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 236 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin 92% copy Near-identical to another mod 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 $0.00004 $0.00236
Opus 5 $0.00002 $0.00118
Sonnet 5 $0.00001 $0.00047
Haiku 4.5 $0.00000 $0.00024

Measured 2d ago against content hash 26e9bf11869e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ruff-linting scanned grade A with 1 finding 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

process = subprocess.Popen(["pbcopy"], stdin=subprocess.PIPE) # ruff: ignore=S603,S607 - Needed for clipboard
Origin

This is a copy

92% identical to ruff-linting — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.cursor/rules/ruff-linting.mdc · 32 lines

What it actually says

Ruff Linting

We use ruff for linting. If there are lint errors, or if the user says "fix lint errors":

  1. Run: ruff check --fix --unsafe-fixes
  2. Repeat until all errors are fixed

Using Targeted Ignores

For legitimate exceptions, use targeted ignores with specific rule codes and explanations:

# Include the rule code and why we're ignoring it
process = subprocess.Popen(["pbcopy"], stdin=subprocess.PIPE)  # ruff: ignore=S603,S607 - Needed for clipboard

result = eval(user_formula)  # ruff: ignore=S307 - Safe: formula validated by parser

api_key = os.getenv("SECRET_KEY")  # ruff: ignore=S105 - Environment variable, not hardcoded

Use # ruff: ignore=RULE_CODE format. Multiple rules: # ruff: ignore=S603,S607

When we fix all errors, celebrate! Clean code feels good. 🌟

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 · 32 lines · 4 tokens per session scan A 26e9bf11869e

Subscribe to this mod's changes

ruff-linting is a cursor rule published in the GitHub repository TechNickAI/ai-coding-config (24 stars, last pushed 2mo ago), licensed MIT. It adds 4 tokens to every session and 236 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). It is 92% identical to ruff-linting, differing in 1 line, and is treated as a copy.