book-analyzer

<Use_When>

• User provides a path to an EPUB or PDF book file
• User says "analyze this book", "process this book", "read this book"
• User wants structured notes from a book-length document (20+ pages) </Use_When>

<Do_Not_Use_When>

• Short documents under 20 pages — use /paper or /process instead
• User wants to read or search specific sections — just use Read tool directly
• User wants EPUB output from markdown — wrong direction
• URL-only input with no file on disk — use /research instead </Do_Not_Use_When>

<Why_This_Exists> Book notes that merely transcribe content are useless — the value is in synthesis. Most book notes in a vault end up sparse because processing a full book manually is exhausting. This skill automates the mechanical work (extraction, splitting, formatting) while delegating the intellectual work (synthesis, assessment, connections) to specialized agents with strict quality constraints. </Why_This_Exists>

<Execution_Policy>

• Run extraction scripts first, verify output before proceeding to analysis
• Delegate chapter analysis to parallel agents (one per chapter, all simultaneous)
• Use Sonnet for chapter analysis, Opus for cross-book synthesis
• Vault integration is conditional — detect .obsidian/ or CLAUDE.md in working directory
• Report progress via TodoWrite at each stage transition
• If extraction fails, stop and report — don't guess at content
• Total chapters capped at 50 — if more, group adjacent chapters into batches </Execution_Policy>

Stage 1: PARSE ARGUMENTS AND EXTRACT

Parse $ARGUMENTS to get the book file path and optional flags.

Argument format:

$ARGUMENTS = "path/to/book.epub"                    # basic
$ARGUMENTS = "path/to/book.pdf --no-terms"          # skip term extraction
$ARGUMENTS = "path/to/book.epub --output ~/Desktop/" # custom output location

Parse logic:

1. Split $ARGUMENTS by spaces, treating quoted paths as single tokens
2. First non-flag token = file path (REQUIRED — stop if missing)
3. Optional flags: --no-terms (skip concept extraction), --output <dir> (custom output)
4. Detect format from file extension: .epub, .pdf, .mobi

Run extraction based on format:

For EPUB:

SKILL_DIR="$(dirname "$(readlink -f "$0" 2>/dev/null || echo "$0")")"
# Find skill directory — check common locations
for dir in .claude/skills/book-analyzer ~/.claude/skills/book-analyzer; do
  if [ -f "$dir/scripts/extract_epub.py" ]; then SKILL_DIR="$dir"; break; fi
done
WORK_DIR=".book-work-$(date +%s)"
python3 "$SKILL_DIR/scripts/extract_epub.py" "INPUT_PATH" "$WORK_DIR"

For PDF:

WORK_DIR=".book-work-$(date +%s)"
"$SKILL_DIR/scripts/extract_pdf.sh" "INPUT_PATH" "$WORK_DIR"

For MOBI: Convert to EPUB first with ebook-convert (calibre), then run EPUB extraction.

The work directory is created inside the vault root (e.g., .book-work-1709398200/). Clean it up after the pipeline completes.

After extraction: Read $WORK_DIR/metadata.json to verify success.

PDF fallback: If metadata shows "needs_fallback": true, use the Claude Read tool instead:

• Read the PDF 20 pages at a time: Read(file_path="INPUT_PATH", pages="1-20"), then pages="21-40", etc.
• Write each batch to $WORK_DIR/pages/page_batch_NNN.txt
• Update metadata with actual content