Book Summarizer

Overview

This skill produces a faithful, well-structured summary of a book at the requested depth — a one-line gist, an executive summary, key takeaways, or chapter-by-chapter notes — capturing the central thesis, the supporting ideas, the most memorable examples, and what the reader can actually do with it.

Keywords: book summary, key takeaways, TL;DR, main idea, chapter summary, executive summary, book notes, book club, nonfiction, study notes.

When to use vs. not

Use this to summarize, extract takeaways from, or build study/discussion notes for a book the reader names or provides. Accuracy first: if you don't actually know a book's content, say so rather than inventing — never fabricate quotes, statistics, or plot points. For very recent or obscure titles, ask the user to paste text or confirm details. Note that a summary is no substitute for reading when nuance matters (e.g., for academic citation).

Inputs to gather first

1. The book (title + author — confirm you have the right one).
2. Depth wanted — one-liner, ~1 page, key takeaways, or chapter-by-chapter.
3. Purpose — decide whether to read it, apply it, prep a discussion, study for an exam, or recall it.
4. Fiction or nonfiction (changes the structure — themes/plot vs. thesis/arguments).
5. Spoiler tolerance for fiction.

Workflow

1. Confirm the book and your confidence. State the title/author and that you can summarize it accurately. If unsure, ask for text or flag the uncertainty up front.
2. Identify the spine. For nonfiction: the central thesis and the 3–7 big ideas that support it. For fiction: premise, central conflict, themes, and arc (respecting spoiler preference). See references/summary-structures.md.
3. Summarize at the requested depth:
   • One-liner: the single core message in a sentence.
   • Executive (~1 page): thesis + key ideas + why it matters.
   • Takeaways: a ranked, actionable bullet list.
   • Chapter-by-chapter: 2–4 lines per chapter capturing each one's point.
4. Keep the best evidence. Preserve the one or two examples, studies, or scenes that make each idea stick — concrete beats abstract.
5. Add actionable takeaways (for nonfiction): what to do differently, as concrete steps.
6. Stay faithful + neutral. Represent the author's argument accurately before adding any critique. Separate "what the book says" from "my take." Flag where the book is contested if relevant.
7. (Optional) discussion/study layer. Book-club questions, key terms, or quiz prompts on request.

Decision framework

Worked example

See examples/atomic-habits.md for layered summaries (one-liner → takeaways → structure) of a well-known nonfiction title.

Best Practices

• Lead with the core message — the reader should get the thesis in the first sentence.
• Faithful before critical — represent the argument accurately, then optionally evaluate.
• Keep concrete examples — they're what makes ideas memorable.
• Make nonfiction actionable — turn ideas into steps.
• Match depth to purpose — don't give chapter notes to someone who wants a TL;DR.
• Flag uncertainty rather than inventing.

Common Pitfalls

• Fabricating quotes, data, or plot when the book isn't actually known — always avoid.
• Listing chapters without extracting each chapter's point.
• Injecting opinion as if it were the author's.
• Losing the thesis in a pile of details.
• Spoiling fiction without asking.
• Over-summarizing to the point the nuance that matters is gone — note when reading the source is necessary.