Book to Skill: a book or a folder of docs as a Claude skill
Book to Skill is a skill by Virgilio Junior that turns a book, or a folder of your own documents, into a new skill: a short SKILL.md with the main frameworks and rules, plus chapter files the agent loads only when a question needs them.
npx skills add virgiliojr94/book-to-skillPasting a whole book into a chat burns tokens and still loses detail. Book to Skill reads the book once and writes a skill from it: a main SKILL.md of about 4,000 tokens with the book's frameworks, decision rules and a chapter index, plus one file per chapter, a glossary, a list of patterns and a cheat sheet. The agent loads a chapter only when your question needs it. The README claims 24 to 51 times fewer tokens than putting the full book in context, on the author's own tests. It works just as well on your project docs as on a published book. For the basics, see Claude Code skills.
Use only the official repo
The author's own security notice, dated August 17, 2026, warns that a re-upload under another GitHub account contained malware that stole browser and crypto-wallet data. That copy is gone, but clones keep appearing. Install from virgiliojr94/book-to-skill and nowhere else.
How it works
- A local Python script pulls the text out of the file: PDF, EPUB, DOCX, HTML, RTF, Markdown or plain text, and Kindle formats through Calibre.
- It asks whether the book is technical or text-heavy and gives a cost estimate before it starts.
- The agent writes the skill to
~/.agents/skills/<name>/, and under Claude Code links it into~/.claude/skills/. - From then on you ask it questions with
/<book-name> <topic>.
| Command | Does |
|---|---|
/book-to-skill ./my-book.pdf | One book into one skill |
/book-to-skill ~/project-docs/ project-knowledge | A folder of documents into a skill with the name you give |
/book-to-skill "~/books/*.epub" my-library | Several books into one skill |
It also has modes to analyze without generating, and to fold new material into a skill you made earlier.
How to install it
npx skills add virgiliojr94/book-to-skillor clone it straight into your skills folder:
git clone https://github.com/virgiliojr94/book-to-skill.git ~/.claude/skills/book-to-skillIt runs in Claude Code, Codex, GitHub Copilot CLI, Amp, OpenCode and others; the README lists each tool's folder. Each format needs its own extractor, such as pdftotext for PDFs or ebooklib for EPUB. Run python3 scripts/extract.py --check to see what's missing; the script asks before installing anything.
Limits
- Scanned PDFs with no text layer won't work. Run them through OCR first, for example with
ocrmypdf. - Copyright. The license covers the converter, not your books. The README says a skill made from a copyrighted book is for your own use only, and the generator avoids copying raw passages.
- Privacy. Extraction is local, but the agent that writes the skill sends the text to its model provider.
- Publishing is optional. At the end it can push the new skill to GitHub; that defaults to a private repo.
When to use it
- A reference book you keep going back to: a style guide, a framework, a standard.
- Your team's docs, so the agent answers from them instead of guessing.
- Study: one skill per textbook, queried chapter by chapter.
To write a skill from your own routine rather than a book, use skill-creator.
Sources
- virgiliojr94/book-to-skill README, SKILL.md and usage docs — GitHub, accessed October 2026
- book-to-skill security notice, August 17, 2026