keep-it-simple

A coding guideline to write only the direct code needed for the requested feature or fix.

In plain words
What is it for?
It helps decide when to use a plain function, when not to add an abstraction, and which validation or error handling is actually needed.
Why use it?
It avoids extra configuration, abstractions, and flexibility that make code harder to understand without solving a current problem.

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/buildmoonshot/skillpacks/keep-it-simple
Any agent
npx skills add buildmoonshot/skillpacks --skill keep-it-simple
Clone the repo
git clone --depth 1 https://github.com/buildmoonshot/skillpacks

Made for: Claude Code, Codex.

Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 383 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 $0.00053 $0.00383
Opus 5 $0.00026 $0.00192
Sonnet 5 $0.00011 $0.00077
Haiku 4.5 $0.00005 $0.00038

Measured 2d ago against content hash b7a00135122b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

keep-it-simple 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.

skills/engineering/intermediate/keep-it-simple/SKILL.md · 32 lines

What it actually says

Keep It Simple

Write the minimum code that solves the actual problem. Speculative complexity is a cost you pay now for a future that usually never arrives.

Defaults

  • Don't build for requirements you don't have. No config options, plugin systems, or "flexibility" nobody asked for. Solve today's problem; generalize later if a second case actually shows up.
  • No abstraction for single use. Don't extract an interface, a base class, or a factory for something used once. Two concrete cases earn an abstraction; one does not.
  • Don't handle impossible cases. Validate real inputs; don't write error handling for states that can't occur in this code path.
  • Prefer the boring solution. A plain function beats a clever pattern when both work. Clever is a tax every future reader pays.

The test

Before adding a layer, ask:

Would a senior engineer look at this and say it's overcomplicated?

If yes, delete the cleverness and write the direct version.

When complexity IS warranted

Real, present requirements justify real structure — genuine duplication, a known second use case, an actual extensibility need someone asked for. The rule isn't "never abstract." It's "don't abstract speculatively." Earn each layer with a concrete reason.

Why this matters

Every speculative abstraction is code to read, test, debug, and maintain — in exchange for flexibility you may never use. The simplest version that works is almost always the right one, and it's far easier to add structure later than to remove it.

Files

What ships with it

1 file 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. 2d ago First seen · 32 lines · 53 tokens per session scan A b7a00135122b

Subscribe to this mod's changes

keep-it-simple is a skill published in the GitHub repository buildmoonshot/skillpacks (2 stars, last pushed 2mo ago), licensed MIT. It adds 53 tokens to every session and 383 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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