book-to-skill

book-to-skill is a skill for Claude Code from Londeren/claude-plugins. It costs 195 tokens per session (3,559 once invoked), scanned A, original, MIT.

A workflow that turns Markdown books, manuals, courses, or transcripts into reusable instructions for an AI agent. It produces a skill folder with instructions, reference sheets, and a record of the source material.

In plain words
What is it for?
Use it to extract a methodology or playbook from one or more Markdown files and package it as an agent skill.
Why use it?
It separates practical methods from background information, so an agent can follow the method without reading the entire source. Source quotes and section references help keep extracted guidance traceable.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions CLAUDE.md; mentions subagents.

Part of the book-to-skill plugin — 1 skill shipped together

Good fit Use it to extract a methodology or playbook from one or more Markdown files and package it as an agent skill.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/londeren/claude-plugins/book-to-skill
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 Londeren/claude-plugins --skill book-to-skill
Clone the repo
git clone --depth 1 https://github.com/Londeren/claude-plugins

Made for: Claude Code.

Or install book-to-skill, 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 book-to-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/londeren/claude-plugins/book-to-skill/github.svg)](https://agentmods.dev/skills/londeren/claude-plugins/book-to-skill)
Your own site
<a href="https://agentmods.dev/skills/londeren/claude-plugins/book-to-skill"><img src="https://agentmods.dev/badge/skills/londeren/claude-plugins/book-to-skill/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 book-to-skill

Your own site · 80×15
<a href="https://agentmods.dev/skills/londeren/claude-plugins/book-to-skill"><img src="https://agentmods.dev/badge/skills/londeren/claude-plugins/book-to-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 195 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,559 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 $0.00195 $0.03559
Opus 5 $0.00097 $0.01780
Sonnet 5 $0.00039 $0.00712
Haiku 4.5 $0.00019 $0.00356

Measured 10d ago against content hash 7c5cad70a330, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

book-to-skill 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 10d 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/book-to-skill/skills/book-to-skill/SKILL.md · 207 lines

How it starts

The opening of the file, as written. The whole thing — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.

From a method to a skill

The pipeline turns a Markdown source into an executable methodology. Input: a .md file or a folder of .md files. Output: a skill folder with a thin SKILL.md, numbered reference sheets in references/, and the build record PROVENANCE.md. The pipeline needs no external skills, scripts, or libraries.

The distinction that governs everything else: a reference guide to a book and a skill carrying a method are different artifacts. A guide answers "what does chapter 7 say". A skill answers "how do I act by this method right now". We build the second.

The test at every step: would this line help an agent that works on the user's material and has never read the book? It would, keep it. It only reports what the source contained, drop it.

<master_rules>

Rules that hold across all phases

They are duplicated below next to the places where they apply. That is deliberate.

1. NEVER ship a unit without an anchor. Every extracted unit carries a verbatim quote from the source and a section address. The anchor is always verbatim and in the source language, never translated: a translated anchor cannot be found by mechanical search. The rule covers all five types of catch, glossary terms and cases included, not rules alone. The point: the anchor is the only thing that mechanically separates what was extracted from what was invented.

2. Do not write on the author's behalf. If an obvious rule is not stated in the source, it does not exist. That the rule is true, that it would improve the skill, that the method looks incomplete without it, that it is "clearly implied", none of that is grounds to add it. Under pressure to be complete a model writes on the author's behalf more often than it lies in quotes, and it is harder to notice.

3. Synthesize, do not transplant. Raw source fragments longer than three sentences never reach the output. The author's names for constructs are kept verbatim: "5 whys", not "the method of successive questions".

Read the full file on GitHub · 207 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 207 lines · 195 tokens per session scan A 7c5cad70a330

Subscribe to this mod's changes

book-to-skill is a skill published in the GitHub repository Londeren/claude-plugins (4 stars, last pushed 16d ago), licensed MIT. It adds 195 tokens to every session and 3,559 once invoked, about $0.0010 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.

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