kernighans-law

kernighans-law is a skill for Claude Code, Codex from The-Artificer-of-Ciphers-LLC/skills-from-the-artificer. It costs 105 tokens per session (813 once invoked), scanned A, original, MIT.

A code-review principle that says debugging is harder than writing code, so code should be simpler than the author’s maximum cleverness. It focuses on readability and leaving room to understand failures later.

In plain words
What is it for?
Use it to review clever one-liners, reduce unnecessary complexity, choose clearer coding styles, and coach developers on maintainable code.
Why use it?
It helps prevent dense code from becoming difficult to debug, review, and maintain. Simpler code gives future readers more clues about the intended behavior.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to review clever one-liners, reduce unnecessary complexity, choose clearer coding styles, and coach developers on maintainable code.

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Install with agentmods
npx agentmods add skills/the-artificer-of-ciphers-llc/skills-from-the-artificer/kernighans-law
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.

Any agent
npx skills add The-Artificer-of-Ciphers-LLC/skills-from-the-artificer --skill kernighans-law
Clone the repo
git clone --depth 1 https://github.com/The-Artificer-of-Ciphers-LLC/skills-from-the-artificer

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for kernighans-law

README.md
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Your own site
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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for kernighans-law

Your own site · 80×15
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Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 813 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00105 $0.00813
Opus 5 $0.00053 $0.00407
Sonnet 5 $0.00021 $0.00163
Haiku 4.5 $0.00011 $0.00081

Measured 12d ago against content hash 1d2e70c19472, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

kernighans-law 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 12d 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.

kernighans-law/SKILL.md · 58 lines

How it starts

The opening of the file, as written. The whole thing — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Kernighan's Law

"Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it?" — Brian Kernighan, 1974 (The Elements of Programming Style)

The core idea

Writing clever code feels good. It demonstrates mastery and intelligence. But if you write code at the absolute limit of your ability to understand, you have no margin left to debug it when something goes wrong — and something will always go wrong.

The smarter move is to write code that is simpler than you're capable of. Leave yourself headroom.

What "clever" code actually costs

Time to understand: Code that is dense, abstract, or uses advanced tricks is hard to read — for you, six months later, and especially for colleagues.

Debugging difficulty: When clever code breaks, the same cleverness that makes it compact also makes the failure mode opaque. You have to fully reconstruct the intent before you can find the bug.

Review friction: Code reviewers who don't immediately understand code are slower and less thorough. Bugs slip through.

Maintenance burden: Anyone who modifies the code must first understand it. Clever code has a high "understanding tax" that gets paid over and over.

Onboarding cost: New team members struggle with overly sophisticated patterns. Institutional knowledge doesn't transfer.

What to prefer instead

Explicit over implicit. If the reader has to mentally execute the code to understand what it does, it's too implicit. Prefer code that says what it means.

Verbose over terse when it aids clarity. A 10-line version that you can read in 30 seconds is faster to work with than a 2-line version that takes 5 minutes to parse.

Boring over brilliant. Use standard patterns that readers recognize instantly. Reserve unusual approaches for cases where they provide genuine, substantial benefits.

Comments that explain why, not what. When cleverness is unavoidable, comment the reasoning — not a restatement of the code. "We use XOR swap here to avoid an allocation in the hot path" is useful. "This swaps a and b using XOR" is not.

Read the full file on GitHub · 58 lines

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. 12d ago First seen · 58 lines · 105 tokens per session scan A 1d2e70c19472

Subscribe to this mod's changes

kernighans-law is a skill published in the GitHub repository The-Artificer-of-Ciphers-LLC/skills-from-the-artificer (4 stars, last pushed 10d ago), licensed MIT. It adds 105 tokens to every session and 813 once invoked, about $0.0005 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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