book-writer: Skill for Claude Code

.claude/skills/fact-check/SKILL.md

fact-check is a skill for Claude Code from tobyilee/book-writer. It costs 151 tokens per session (1,445 once invoked), scanned A, original, MIT.

A fact-checking workflow for concrete claims in book chapters, such as numbers, quotes, software versions, release dates, API details, and safety information. The checks depend on whether the book is technical or practical.

In plain words
What is it for?
Use it to verify factual statements in technical books and to check safety, health, food, travel-law, or regulatory claims in practical books.
Why use it?
It helps prevent readers from receiving incorrect details, especially claims that change over time or could affect health, safety, or legal decisions.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is tobyilee/book-writer's own configuration. It tells Claude Code how to work on book-writer itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything book-writer configures →

Reuse

Borrowing it

Nothing to install: this file belongs to tobyilee/book-writer. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/tobyilee/book-writer/main/.claude/skills/fact-check/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/tobyilee/book-writer

Made for: Claude Code.

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 fact-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/tobyilee/book-writer/fact-check/github.svg)](https://agentmods.dev/skills/tobyilee/book-writer/fact-check)
Your own site
<a href="https://agentmods.dev/skills/tobyilee/book-writer/fact-check"><img src="https://agentmods.dev/badge/skills/tobyilee/book-writer/fact-check/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 fact-check

Your own site · 80×15
<a href="https://agentmods.dev/skills/tobyilee/book-writer/fact-check"><img src="https://agentmods.dev/badge/skills/tobyilee/book-writer/fact-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 151 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,445 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00151 $0.01445
Opus 5.5 $0.00060 $0.00578
Sonnet 5.5 $0.00030 $0.00289
Haiku 4.5 $0.00015 $0.00145

Measured 1mo ago against content hash e4698578e84c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

fact-check 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 1mo 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.

.claude/skills/fact-check/SKILL.md · 75 lines

How it starts

The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fact Check

원고의 구체적 사실 주장을 검증하고 정정한다. 문체가 아니라 정확성만 본다. 범위는 장르가 정한다 — tech-book은 구체 주장 전반(빠르게 변하는 기술일수록 시점 명기와 출처 대조가 핵심), practical은 안전·건강·법규 사실만(틀리면 독자가 다친다). 다른 장르에서는 이 단계가 없다.

검증 대상

구체적이고 확인 가능한 주장만 본다. 의견·비유·일반 서술은 대상이 아니다.

tech-book — 구체 주장 전반:

유형 예시
수치·통계·벤치마크 "응답이 3배 빨라진다", "메모리 40% 절감"
인용·귀속 "Dijkstra가 말했듯이", "공식 문서에 따르면"
버전 번호 "React 18", "Python 3.12"
릴리스 연도·시점 "2023년에 도입된", "최신 버전에서는"
API·시그니처 함수명·플래그·옵션명·기본값
단정 "최초의", "유일한", "가장 빠른"
참고문헌 식별자·등급 DOI·arXiv ID·URL, 항목별 확인 등급 라벨

practical — 안전·건강·법규 사실만:

유형 예시
식품 안전 수치 조리 심부 온도("닭고기 75℃"), 보관 기간, 해동 규칙
알레르겐·독성 익혀야 하는 재료, 교차 오염, 알레르기 유발 표시
응급·부상 대처 화상·베임 등 사고 시 대처 서술
여행 법규·안전 비자·통관 규정, 현지 법, 안전 수칙
안전 단정 "~해도 안전하다", "괜찮다"류 단정

맛·취향·팁·모호한 분량은 대상이 아니다. 안전 경고가 있는지·어디 있는지는 문체 체크리스트 소관이고, 여기서는 그 값이 맞는지를 본다. 안전 주장은 레퍼런스로 확정되지 않으면 모두 웹으로 확인하며, 공공 보건·식품 안전 기관(식약처·FDA·USDA 등)과 정부 여행 안전 공지를 1차 출처로 삼는다.

(사실 확인 필요) 주석이 달린 지점을 먼저 본다.

판정과 처리

라벨 의미 원고에 반영할 것
✅ 확인됨 레퍼런스와 일치 그대로 둔다
❌ 정정 레퍼런스와 불일치 맞는 값·표현으로 고친다
⚠️ 출처 없음 근거를 찾지 못함 약화("더 빠르다")하거나 삭제한다
🕒 신선도 시점 미명기·곧 바뀔 내용 "{버전}/{연도} 기준" 또는 휘발성 문구를 붙인다

대조 순서: 01_reference.md와 research/*.md로 먼저 판정한다. 거기서 판정할 수 없는 핵심 주장, 그리고 의심스러운 식별자(형식이 이상하거나 빌드 날짜보다 미래 YYMM인 arXiv ID, 열리지 않는 DOI·URL, 출처가 한 곳뿐이고 확인되지 않는 인용)는 WebSearch·WebFetch로 공식 문서·1차 출처를 확인한다. 확인되지 않은 의심 식별자는 ✅가 될 수 없다 — 원고에서 빼거나 출처 없는 일반 서술로 바꾼다.

정정은 원고의 voice를 유지하는 최소 수정으로 한다. 약화·삭제로도 처리할 수 없는 경우(그 주장이 장의 논지를 떠받치고 있어서 빼면 장이 무너지는 경우)만 미해소로 남기고 보고한다.

로그 ({slug}/factcheck_log.md)

로그는 단일 파일이다. 장마다 판정이 끝나는 즉시 섹션을 append한다 — 중단돼도 끝낸 판정이 남는다.

## {NN}장 (라운드 {N})

### ❌ 정정
- "React 18에서 도입된 Server Actions" → "React 19에서 안정화된 Server Actions" — 근거: research/web.md 자료 4 (공식 릴리스 노트)
### ⚠️ 약화·삭제
- "이 방식이 3배 빠르다" → "더 빠르다" — 레퍼런스에 근거 없음
### 🕒 신선도
- "최신 버전에서는" → "PostgreSQL 16 기준으로는"
### ✅ 확인 (요약)
- 수치 4건, 버전 3건 — research/web.md·papers.md와 일치
### 미해소
- (없음)

Read the full file on GitHub · 75 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. 1mo ago Changed · -35 lines · +6 tokens per session e4698578e84c
  2. 2mo ago First seen · 110 lines · 145 tokens per session scan A 1fb92676d4a9

Subscribe to this mod's changes

fact-check is a skill published in the GitHub repository tobyilee/book-writer (85 stars, last pushed 3d ago), licensed MIT. It adds 151 tokens to every session and 1,445 once invoked, about $0.0006 per session on Opus 5.5. 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 2026-08-30.

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