clean-code

A set of guidelines for making code easier to read, understand, review, and change. It covers names, functions, formatting, errors, comments, classes, and common code smells.

In plain words
What is it for?
Use it while writing code, reviewing pull requests, refactoring older code, finding code smells, or setting shared coding standards.
Why use it?
It helps reduce confusing structure and maintenance problems in new or existing code.

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/fellipeutaka/leon/clean-code
Any agent
npx skills add fellipeutaka/leon --skill clean-code
Clone the repo
git clone --depth 1 https://github.com/fellipeutaka/leon

Made for: Claude Code, Codex.

Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,033 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 $0.00067 $0.02033
Opus 5 $0.00034 $0.01017
Sonnet 5 $0.00013 $0.00407
Haiku 4.5 $0.00007 $0.00203

Measured yesterday against content hash e6c795dd3c27, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

clean-code 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 yesterday.

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.

skills/clean-code/SKILL.md · 233 lines

How it starts

The opening of the file, as written. The whole thing — 233 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Clean Code

Principles for transforming "code that works" into "code that is clean" — code that can be read, understood, and enhanced by any developer.

"Code is clean if it can be understood easily — by everyone on the team." — Dave Thomas

When to Apply

Reference these guidelines when:

  • Writing new code and choosing names, function signatures, structure
  • Reviewing pull requests for readability and maintainability
  • Refactoring legacy code or reducing complexity
  • Identifying and fixing code smells
  • Improving team code standards

Rule Categories

Priority Category Impact
1 Naming HIGH — affects every line of code
2 Functions HIGH — core unit of abstraction
3 Code Smells HIGH — early detection prevents rot
4 Formatting MEDIUM — readability at a glance
5 Error Handling MEDIUM — robustness and clarity
6 Comments MEDIUM — most are avoidable
7 Object Calisthenics ASPIRATIONAL — exercises for better OO design

1. Naming

Good names are the single most impactful thing you can do for readability.

Priority order:

  1. Consistency — same concept = same name everywhere
  2. Intent-revealing — name says what it does, not how
  3. Specific — avoid vague names like data, info, manager, handler, utils
  4. Searchable — unique enough to grep
  5. Brief — short but not cryptic
// Bad
const d = new Date();
const arr = users.filter((u) => u.a);
function process(data: any) {}

// Good
const createdAt = new Date();
const activeUsers = users.filter((user) => user.isActive);
function validatePayment(payment: Payment) {}

Conventions:

  • Classes/types: nouns (Customer, OrderRepository). Avoid Manager, Data, Info.
  • Methods/functions: verbs (createOrder, validateEmail, isEligible)
  • Booleans: question form (isActive, hasPermission, canWithdraw)
  • Collections: plural nouns (users, orderItems)

Read the full file on GitHub · 233 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 233 lines · 67 tokens per session scan A e6c795dd3c27

Subscribe to this mod's changes

clean-code is a skill published in the GitHub repository fellipeutaka/leon (5 stars, last pushed 3d ago), licensed MIT. It adds 67 tokens to every session and 2,033 once invoked, about $0.0003 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 2026-08-31.

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