book-to-skill

<p align="center">
  <img src="docs/assets/banner.webp" alt="Booklin, the book-to-skill wizard, holding an open book whose pages scatter into sparkles that settle into an ordered grid" width="100%">
</p>

<h1 align="center">book-to-skill</h1>

<p align="center">
  <a href="README.md"><strong>English</strong></a> ·
  <a href="README.ru.md">Русский</a>
</p>

<p align="center">
  <strong>Turn any technical book, document folder, or collection of sources into a unified agent skill — ready to study, reference, and use while you work in GitHub Copilot CLI, Amp, or Claude Code.</strong>
</p>

<p align="center">
  <a href="https://github.com/virgiliojr94/book-to-skill/releases"><img src="https://img.shields.io/github/v/release/virgiliojr94/book-to-skill?style=for-the-badge&color=blueviolet" alt="Latest release"></a>
  <img src="https://img.shields.io/badge/Agent_Skills-Open_Standard-blueviolet?style=for-the-badge" alt="Agent Skills standard">
  <img src="https://img.shields.io/badge/PDF%20%E2%80%A2%20EPUB%20%E2%80%A2%20DOCX%20%E2%80%A2%20MD%20%E2%80%A2%20HTML%20%E2%80%A2%20RTF%20%E2%80%A2%20MOBI-supported-green?style=for-the-badge" alt="Formats supported">
  <img src="https://img.shields.io/badge/License-MIT-blue?style=for-the-badge" alt="MIT License">
  <a href="https://github.com/sponsors/virgiliojr94"><img src="https://img.shields.io/github/sponsors/virgiliojr94?style=for-the-badge&color=ea4aaa&logo=githubsponsors&logoColor=white" alt="Sponsor"></a>
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<p align="center">
  <a href="#-why">Why</a> ·
  <a href="#-what-it-generates">What it generates</a> ·
  <a href="#-beyond-books">Beyond books</a> ·
  <a href="docs/how-it-works.md">How it works</a> ·
  <a href="docs/usage.md">Usage</a> ·
  <a href="docs/install.md">Install</a> ·
  <a href="docs/faq.md">FAQ</a> ·
  <a href="docs/performance.md">Performance</a> ·
  <a href="docs/architecture.md">Architecture</a> ·
  <a href="CHANGELOG.md">Changelog</a>
</p>

<p align="center">
  <strong>24×–51× fewer tokens than dumping the book into context</strong> to answer one question, measured on real books (<a href="docs/performance.md#the-discovery-loop-tax">how it's measured</a>).
</p>

**How it works, in 3 steps:**

1. **Point** it at a file, folder, or glob — `/book-to-skill ./my-book.pdf`
2. **It distills** the book into a skill — frameworks, decision rules, anti-patterns, and per-chapter files. Structure, not a summary.
3. **Your agent loads it on demand** — ask `/my-book replication` and it reads the right chapter and answers from the real content, no hallucination.

---

## 🤔 Why

<img align="right" width="200" src="docs/assets/booklin.png" alt="Booklin — the book-to-skill mascot, a purple wizard holding a book">

You buy a great technical book. You read it once. Three months later you can't remember chapter 7 existed.

The usual workarounds don't help:
- 📄 "Let me just search the PDF" → you get a list of pages, not answers
- 🧠 "I'll ask the agent about this book" → it either hallucinates or says it doesn't have the content
- 📝 "I'll take notes as I read" → you end up with a 200-line doc you never open again

**book-to-skill solves this by turning the book into a structured skill your agent loads on demand.**

Once installed, you just type `/your-book-slug replication` and the agent reads the right chapter and answers from the actual content. No hallucination. No digging through PDFs. The book becomes part of your workflow.

Works with any host that supports the open [Agent Skills](https://github.com/agentskills/agentskills) standard — GitHub Copilot CLI, Amp, and Claude Code all read the same `SKILL.md` format.

---

## 📦 What it generates

Running `/book-to-skill your-book.pdf` (or a folder, glob, or list of files) creates a full skill in your agent's skills directory (`~/.copilot/skills/<slug>/` for Copilot CLI, `~/.agents/skills/<slug>/` for Amp or cross-agent, `~/.claude/skills/<slug>/` for Claude Code):

| File | Purpose | Size |
|------|---------|------|
| `SKILL.md` | Core mental models + chapter index | ~4,000 tokens |
| `chapters/ch01-*.md` … | One file per chapter, loaded on-demand | ~1,000 tokens each |
| `glossary.md` | Every key term, alphabetically sorted with chapter refs | ~1,500 tokens |
| `patterns.md` | All techniques, algorithms, and design patterns | ~2,000 tokens |
| `cheatsheet.md` | Decision tables and quick-reference rules | ~1,000 tokens |

**Chapter files are loaded on-demand** — they don't count against the skill budget until you ask about that topic.

---

## 🏢 Beyond books

The name says "book", but the input is any structured prose. The same extraction works on knowledge you own and re-read constantly:

- **Internal documentation** — architecture decision records, runbooks, onboarding guides. Fold a whole `docs/` folder into one skill and ask it while you code.
- **Brand & design systems** — voice guidelines, tone-of-voice docs, component principles. Turn a brand book into a skill your team queries instead of skimming a 60-page PDF.
- **Research clusters** — a stack of papers plus your own notes, merged into a single unified skill and updated as new material lands (see [Update / fold-in](#-usage)).
- **Specs & standards** — RFCs, API contracts, compliance docs you reference but never memorize.

If you re-open a document often enough to wish you'd memorized it, it's a candidate.

---


## 🧾 The Discovery Loop Tax

A PDF-reading agent doesn't just read — it *navigates*: it re-fetches the ToC, backtracks, and re-processes all of it on every turn. book-to-skill pays that structuring cost **once**, at conversion, so queries stay proportional to the answer — **24×–51× fewer tokens** than dumping the book into context, measured on real books.

📊 **Full methodology, numbers, and per-book tables → [docs/performance.md](docs/performance.md#the-discovery-loop-tax)**

---

## ⚙️ How it works

Two halves: a deterministic Python **extractor** (document → clean text + metadata) and a spec-driven **generator** (your agent follows `SKILL.md` to turn that into a structured skill). On-demand chapter files keep the loaded skill small.

🔧 **Full walkthrough (Steps 0–10, extraction modes, token budgets) → [docs/how-it-works.md](docs/how-it-works.md)**

---

## 🚀 Usage

`/book-to-skill <path|folder|glob> [skill-name]` — plus analyze-only, generate-from-analysis, and update/fold-in modes. After a conversion, the converter can publish the skill to GitHub (private by default) so any host installs it with `npx skills add`.

▶️ **All modes and examples → [docs/usage.md](docs/usage.md)**

💬 **In practice → [use cases](https://github.com/virgiliojr94/book-to-skill-use-cases)** — a DevEx book became a survey of 300+ engineers; a scanned PDF that stalled became [#130](https://github.com/virgiliojr94/book-to-skill/pull/130). Add yours: the account lives in your own Gist, the index takes a one-line PR.

---

## 📥 Install

```bash
# One command, any host — via the cross-agent skills CLI:
npx skills add virgiliojr94/book-to-skill

# Or manually — clone into your skills folder (registers /book-to-skill):
git clone https://github.com/virgiliojr94/book-to-skill.git ~/.claude/skills/book-to-skill
# (Copilot CLI: ~/.copilot/skills/ · Amp/cross-agent: ~/.agents/skills/)
```

📥 **All hosts, optional extractors, and the standalone CLI → [docs/install.md](docs/install.md)**

---

## ❓ FAQ

Common questions — "why not just dump the PDF?", cost, privacy, non-book inputs, multi-file books.

❓ **Answers → [docs/faq.md](docs/faq.md)**

---

<details>
<summary>🔧 <strong>Requirements</strong></summary>


The extractor tries tools in order per format and uses the first available. If nothing is installed, it tells you which command to run. Plain text, Markdown, reStructuredText and AsciiDoc need no extra deps.

> **Check your setup in one command:** `python3 scripts/extract.py --check` prints which extractors are installed for every format and the exact command to install anything missing — no file needed.

**PDF — choose by book type:**

| Book type | Tool | Install | Speed |
|-----------|------|---------|-------|
| Text-heavy (prose, few tables) | `pdftotext` (poppler) | `sudo apt install poppler-utils` | ⚡ instant |
| Text-heavy fallback | `pypdf` | `pip3 install pypdf` | ⚡ instant |
| Text-heavy fallback | `pdfminer.six` | `pip3 install pdfminer.six` | ⚡ instant |
| **Technical (code, tables, formulas)** | **`docling`** | `pip3 install docling` | ~1.5s/page |

> Before extraction begins, the skill asks you whether the book is **technical** or **text-heavy** and picks the right tool automatically. Docling preserves markdown tables and code blocks; pdftotext is faster for prose-only books.

> **Scanned PDFs need OCR first.** A PDF that is page images with no text layer — a photographed or scanned book — has nothing for these tools to extract. The extractor checks the first pages and stops immediately with an explanation, rather than working through the whole book to produce an empty skill. Run OCR yourself, then convert the result:
>
> ```bash
> ocrmypdf input.pdf output.pdf
> ```

**EPUB:**

| Tool | Install | Quality |
|------|---------|---------|
| `ebooklib` + `beautifulsoup4` | `pip3 install ebooklib beautifulsoup4` | ⭐⭐⭐ Best |
| stdlib `zipfile` | built-in