prefer-builtin-update

prefer-builtin-update is a skill for Claude Code from ncaq/konoka. It costs 44 tokens per session (775 once invoked), scanned A, original, Apache-2.0.

A file-editing rule for coding assistants. It requires them to use built-in editing tools for changes instead of short shell or Python replacement commands.

In plain words
What is it for?
Use it when editing, replacing, or rewriting files, especially when a human needs to inspect the exact proposed change.
Why use it?
It makes each change easier to review before it runs and reduces the risk of replacing the wrong text or damaging a file.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Part of the prefer-builtin-update plugin — 1 skill shipped together

Good fit Use it when editing, replacing, or rewriting files, especially when a human needs to inspect the exact proposed change.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ncaq/konoka/prefer-builtin-update
View source ↗ ncaq/konoka
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 ncaq/konoka --skill prefer-builtin-update
Clone the repo
git clone --depth 1 https://github.com/ncaq/konoka

Made for: Claude Code.

Or install prefer-builtin-update, the plugin that ships this one along with the rest of its 1 skill.

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 prefer-builtin-update

README.md
[![agentmods](https://agentmods.dev/badge/skills/ncaq/konoka/prefer-builtin-update/github.svg)](https://agentmods.dev/skills/ncaq/konoka/prefer-builtin-update)
Your own site
<a href="https://agentmods.dev/skills/ncaq/konoka/prefer-builtin-update"><img src="https://agentmods.dev/badge/skills/ncaq/konoka/prefer-builtin-update/github.svg" alt="Measured on agentmods" height="20"></a>

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 prefer-builtin-update

Your own site · 80×15
<a href="https://agentmods.dev/skills/ncaq/konoka/prefer-builtin-update"><img src="https://agentmods.dev/badge/skills/ncaq/konoka/prefer-builtin-update.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 775 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 $0.00044 $0.00775
Opus 5 $0.00022 $0.00387
Sonnet 5 $0.00009 $0.00155
Haiku 4.5 $0.00004 $0.00077

Measured 9d ago against content hash dcc40539bfea, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

prefer-builtin-update 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 9d 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.

plugins/prefer-builtin-update/skills/prefer-builtin-update/SKILL.md · 66 lines

What it actually says

ファイル更新には組み込みのEditツールを使う

ファイルの内容を書き換える用事に、 sedやperlやPythonなどのプログラムを持ち出さないでください。 組み込みのEditツールを使ってください。 ファイルの新規作成や全体の書き直しにはWriteツールを使ってください。

理由

Editツールは変更箇所が差分として表示されるため、 承認する人間が実行前に何が変わるのかを正確に確認できます。 プログラムによる置換は実行するまで結果が分からず、 毎回スクリプトの中身を読んで安全性を判断する負担が発生します。 実行後の差分も読みにくくなります。

Editツールは対象文字列が一意に定まらなければ失敗するため、 意図しない箇所を巻き込む事故が起きにくいです。 sedの正規表現による置換は想定外の行にもマッチして、 気付かないうちにファイルを壊すことがあります。

汎用スクリプト言語のワンライナーは、 シェルのクォートとスクリプト側のクォートが干渉して壊れやすく、 リトライを繰り返す原因にもなります。

対比

避ける:

sed -i 's/foo/bar/' src/main.rs
perl -i -pe 's/foo/bar/' README.md
python3 -c "content = open('config.json').read().replace('foo', 'bar'); open('config.json', 'w').write(content)"

使う: Editツールで書き換え前後の文字列を指定して置き換えます。 複数箇所を書き換える場合も、 Editツールを箇所ごとに呼び出してください。

例外

ものすごい量の機械的な置換で、 Editツールでは呼び出し回数が現実的でない場合に限り、 プログラムによる置換を使って構いません。

その場合もワンライナーは使わず、 Writeツールで置換処理をスクリプトファイルとして書き出してから実行してください。 ファイルとして残すことで人間が実行前に内容を検証できます。 実行前に対象ファイルの範囲と置換内容を説明し、 実行後はgit diffなどで結果の差分を確認してください。

hookによる補助

このプラグインのPreToolUseフックが、 Bashツール経由のin-place編集やワンライナーによるファイル書き込みを検出して拒否します。 リトライ往復を削減するための補助動作なので、 依存しないでください。 フックは全ての書き換えパターンを検出できません。 なので最初からEditツールを使ってください。

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. 9d ago First seen · 66 lines · 44 tokens per session scan A dcc40539bfea

Subscribe to this mod's changes

prefer-builtin-update is a skill published in the GitHub repository ncaq/konoka (3 stars, last pushed 2d ago), licensed Apache-2.0. It adds 44 tokens to every session and 775 once invoked, about $0.0002 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.