book-to-skill: turn any technical PDF into a Claude Code skill

book-to-skill is a Claude Code skill by virgiliojr94 that ingests a technical book or document — PDF, EPUB, DOCX, Markdown, or HTML — and converts it into a structured, indexed agent skill. The output is not a summary: it is a multi-file skill with chapter indexes, a glossary, a patterns guide, and a decision cheatsheet, shaped specifically for on-demand retrieval by your coding agent.

When It Shines

If you have ever copy-pasted 80 pages of docs into a prompt just to answer one question, this is the fix. The author measured 24×–51× fewer tokens compared to dumping an entire book into context — the skill loads only the chapter relevant to your question, leaving the rest of the window free for actual work.

It is also format-agnostic in a way that matters for real work: it handles internal runbooks, architecture decision records, and onboarding guides just as well as published books. The generated skill uses the open Agent Skills standard, so it works identically in Claude Code, GitHub Copilot CLI, and Amp — you convert once and it runs everywhere.

The Real Catch

Scanned PDFs — the kind every internal doc inevitably is — need OCR preprocessing before the tool can touch them. That step is on you. You will also need Python 3 plus format-specific system packages: poppler for PDFs, docling for EPUB, and so on. That is a non-trivial setup for something that could otherwise be a one-line install. And if you are thinking of converting a copyrighted third-party book, the README is explicit: keep that generated skill private.

Quick Start

# Install the skill
npx skills add virgiliojr94/book-to-skill

# Convert a book and name the output skill
/book-to-skill ~/books/designing-data-intensive-applications.pdf ddia

Your agent now has /ddia available. Ask it about leader-based replication and it will pull the right chapter — not hallucinate from training data, not eat your token budget on material you are not even using.

Built by virgiliojr94. Source and full docs at github.com/virgiliojr94/book-to-skill.