book-to-skill

<!--
Cross-agent notes (informational; ignored by host agents):
  - Compatible skill roots: GitHub Copilot CLI (~/.copilot/skills, ~/.agents/skills,
    .github/skills, .claude/skills, .agents/skills), Amp (.agents/skills,
    ~/.config/agents/skills, ~/.config/amp/skills), Claude Code (~/.claude/skills),
    Hermes Agent ($HERMES_HOME/skills, .hermes/skills, .agents/skills).
  - `allowed-tools` is intentionally omitted to stay agent-neutral: Copilot CLI uses
    `shell`/MCP-server names, Claude uses `Bash`/`Read`/`Write`/`Glob`/`Grep`, Amp
    adds `shell_command`. The skill needs shell (to run extract.py) and file
    read/write — each host will prompt for those on first use.
  - Argument hint: <path-to-document-folder-or-glob>... [skill-name-slug]
-->

# Book-to-Skill Converter

Transform written knowledge into actionable agent skills by extracting structure — not producing summaries.

## Philosophy

Books contain crystallized expertise: frameworks, principles, and techniques that took years to develop. This skill extracts that knowledge into a format GitHub Copilot CLI, Amp, Claude Code, Hermes Agent, or another compatible agent can leverage repeatedly.

**Extract structure, not summaries.** A skill isn't a book report. It's a toolkit of:
- Named frameworks (mental models with clear application)
- Actionable principles (rules that guide decisions)
- Techniques (step-by-step methods)
- Anti-patterns (what to avoid and why)
- Voice calibration (how the author thinks and communicates)

**Preserve the author's precision.** Frameworks often have specific names for reasons. "The 5 Whys" isn't interchangeable with "ask why multiple times." Capture the exact formulation.

**Layer depth appropriately.** Simple books → simple skills. Complex books with 10+ frameworks → skills with reference files and on-demand chapters.

---

## Modes of Operation

Four paths available. Route based on what the user asks:

### 1. Full Conversion (Default)
**Trigger:** User provides one or more document/directory/glob paths without special instructions
**Action:** Run all steps below (Steps 0–9)
**Output:** Complete skill with SKILL.md, chapters/, glossary, patterns, cheatsheet

### 2. Analyze Only
**Trigger:** User says "analyze", "just extract", or "I want to review before generating"
**Action:** Run Steps 0–3, then produce a structured extraction report (frameworks, principles, techniques found). Stop — do NOT generate skill files.
**Output:** Analysis report for user review

### 3. Generate from Prior Analysis
**Trigger:** User has existing analysis notes or previously ran analyze-only
**Action:** Skip Steps 0–3, use the provided analysis as input, run Steps 4–9
**Output:** Skill files from the provided analysis

### 4. Update / Fold-in (Existing Skill)
**Trigger:** User provides one or more new source paths and indicates they want to update an existing skill (either by pointing to the existing skill folder, providing a skill slug that already exists in `SKILLS_HOME`, or explicitly requesting an update).
**Action:** Run Step 0 (out-of-scope check), Step 1 (validate inputs), Step 1.5 (identify book type), and Step 2 (extract new files). Then skip to Step 5 (identify/detect existing skill path) and run the **Update / Fold-in Workflow** to merge the new content into the existing skill files.
**Output:** Updated existing skill with new/revised chapter summaries and merged indexes/glossaries.

---

## Skill Locations

This converter can run from multiple skill systems. When looking for this converter's helper script or writing the generated book skill, prefer these locations in order:

1. GitHub Copilot CLI personal skills: `~/.copilot/skills/`
2. Cross-agent personal skills (Copilot, Amp, Codex): `~/.agents/skills/`
3. Claude Code personal skills: `~/.claude/skills/`
4. Project-local Copilot skills: `.github/skills/`
5. Project-local Claude skills: `.claude/skills/`
6. Project-local Amp / Copilot skills: `.agents/skills/`
7. Amp global skills: `~/.config/agents/skills/`
8. Amp legacy global skills: `~/.config/amp/skills/`
9. Hermes Agent personal skills: `$HERMES_HOME/skills/` (defaults to `~/.hermes/skills/`)
10. Hermes Agent project skills: `.hermes/skills/` or `.agents/skills/`

For **generated** book skills, pick a destination that the user's host agent can actually discover (see Step 5). When more than one valid root exists, ask the user once and remember the answer for the session — do not silently default.

---

## Step 0 — Out-of-scope check

If no arguments are provided, stop and respond:
> "book-to-skill requires a supported document path, folder, or glob pattern. Usage: `book-to-skill <path-to-document-folder-or-glob>... [skill-name-slug]`"

Throughout the workflow:
- Identify the input paths and the optional skill slug.
- If the last argument is not a file, folder, or glob that exists or matches any files, and it looks like a skill slug (e.g. lowercase hyphens, alphanumeric), treat it as `SKILL_NAME`.
- Treat all other arguments as the list of `INPUT_PATHS`.
- If any input path is an existing skill directory (contains `SKILL.md` and a `chapters/` sub-folder), or if `SKILL_NAME` matches an existing skill slug in `SKILLS_HOME`, flag this run as an **Update/Fold-in** operation (Mode 4).

---

## Step 1 — Validate input

Verify that there is at least one supported file, directory, or glob pattern among the `INPUT_PATHS`.
For directories and globs, expand them to find matching supported files (`.pdf`, `.epub`, `.docx`, `.txt`, `.md`, `.markdown`, `.rst`, `.adoc`, `.html`, `.htm`, `.rtf`, `.mobi`, `.azw`, `.azw3`).

If no supported files are found, stop with a clear error message.

---

## Step 1.5 — Identify content type

Before extracting, ask the user:

> "What kind of content do these sources have? This helps me choose the best extraction method.
>
> 1. **Technical** — has code blocks, tables, formulas, diagrams (e.g. programming books, academic papers, architecture guides)
> 2. **Text-heavy** — mostl