clean-code

A set of general coding principles for every code change, regardless of programming language. It emphasizes clear code, safe error handling, attention to edge cases, and tests for failure paths.

In plain words
What is it for?
Use it whenever changing code in Python, JavaScript, TypeScript, Go, or another language, including when reviewing how errors and tests are handled.
Why use it?
It helps prevent code that hides errors, breaks on unusual input, or is difficult to understand and maintain.

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

Made for: Claude Code, Codex.

Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 10,467 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 $0.00065 $0.10467
Opus 5 $0.00032 $0.05234
Sonnet 5 $0.00013 $0.02093
Haiku 4.5 $0.00006 $0.01047

Measured yesterday against content hash 01514a8b9574, 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/audit-fail-closed.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

src/core/skills/clean-code/SKILL.md · 587 lines

How it starts

The opening of the file, as written. The whole thing — 587 lines — stays where its author put it; the contents beside it link to each section on GitHub.

This skill enforces universal coding principles on every code change. It is stack-agnostic — same rules hold for Python backends, TypeScript frontends, Go services, and any other language the project uses. Stack-specific layering (Django ORM, FastAPI dependencies, Fiber middleware, React hooks) lives in the matching stack skill that depends on this one.

Read the why, not just the diff. Every rule below pairs the wrong shape (BAD) with the right one (GOOD) and the reason the right one is right — and the reason is the point. Internalize it and you apply the principle where no rule is written (the out-of-distribution case that no linter catches); copy the GOOD diff alone and you only pass the cases someone already enumerated. These tactics are the concrete expression of the project's constitution values — smallest-correct-change, docs-are-the-contract, agent-agnostic — which carry the WHY one level up. (This is the Teaching Claude Why finding applied to ourselves: a principle understood generalizes; a demonstration copied does not.)

Strategic parent: This skill enforces the tactical shape of code (naming, structure, error paths). The strategic anti-overengineering rule — reuse first, no speculation, diff-minimal, rule-of-three abstraction — lives in src/core/rules/anti-overengineering.md and applies to every artifact (docs, hooks, skills, templates, tests, CLI), not just code. Read it before introducing a new abstraction.

Pre-Code Checklist

Before writing any code, verify you have read the relevant context:

  • Read the engineering doc for the surface being changed (each stack ships its own under docs/engineering/<stack>-rules.md, docs/engineering/frontend-rendering-rules.md, or the meta-repo's docs/architecture/meta-project.md).
  • If touching error handling or API responses: read api-contract-discipline.md and the project's error-envelope doc (docs/engineering/mcp-error-envelope.md for cos_* MCP tools, docs/api-contracts/error-format.md for HTTP services).
  • If touching auth, payments, or file uploads: read docs/playbooks/security-review.md.
  • Search the repo for existing patterns before introducing new ones — see the search skill for the grounded-count workflow.
  • Before adding code to a service subtree in a polyglot project, confirm placement against the docs/engineering/project-anatomy.md SSOT: same-language reuse lives in src/shared/<lang>/, cross-language types in src/shared/contracts/ — see §7.

Read the full file on GitHub · 587 lines

Files

What ships with it

5 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 · 587 lines · 65 tokens per session scan A 01514a8b9574

Subscribe to this mod's changes

clean-code is a skill published in the GitHub repository kouroshez/coding-os (6 stars, last pushed yesterday), licensed Apache-2.0. It adds 65 tokens to every session and 10,467 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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