I asked an AI to explain my book without spoiling it

Every reader knows the moment. You are halfway through a book, a name comes up that you should remember, and you do not. Or you have put the book down for two weeks and lost the thread. You want someone to explain it, and you do not want to hear what happens next.

So here is what that looks like in BookBuddy, worked through on a book you probably know.

The setup

Take Der kleine Prinz, the German edition of The Little Prince, open on page 20. By that point the pilot has crash-landed in the desert, drawn the sheep, heard about the rose, and the little prince has just visited his first asteroid.

The two questions below are the ones that matter for spoilers: one asking for a recap, one asking straight out how it ends. What follows each is an illustrative answer, written to show the shape and the boundary of a reply at that point in the book. It is not a transcript of any one session.

Question 1: "I'm reading along. Briefly, what has happened so far?"

An answer of that kind, in three paragraphs:

So far we have followed a pilot who is stranded in the Sahara after his plane breaks down. There he meets the little prince, a mysterious child from another planet. The story starts much earlier, though, with the pilot's childhood, when he gave up drawing because the grown-ups mistook his boa constrictor digesting an elephant for a hat. [...]

In their conversations the pilot learns more about the prince's home, the tiny asteroid B 612: cleaning out volcanoes and pulling up the baobabs that would otherwise break the planet apart. Most important is his complicated relationship with a proud flower that he loved, but whose contradictions made him leave. [...]

Most recently the prince set out to visit neighbouring asteroids. On the first he met a king who considers himself the absolute ruler of the universe, although he lives alone on his planet. [...] The prince soon got bored and moved on.

Everything in it comes from the first 20 pages, and it stops exactly where the reader is: leaving the king. A real answer also quotes the book's own sentences, in the book's own language, and tapping a quote opens the book at that passage so you can check it.

Question 2: "How does the story end? Does the little prince get back to his rose?"

This is the question a general chatbot answers happily, and the one that ruins the rest of the book. Here it gets refused, and a refusal reads like this:

I can't tell you at this point how the story ends, or whether the little prince actually returns to his flower. As your reading companion, I only discuss the book up to the point you have already read, so nothing gets spoiled.

Here is what we know so far about his journey and his reasons: [...]

What follows a refusal is what the pages already read do support: the painful goodbye to the flower, the prince's homesickness for his planet, the lesson from the king. What it will not do is lean either way on the ending.

No hint in either direction. The question does not get a vague answer; it gets a clear no, and then the things the reader is actually entitled to.

Why it can do this

BookBuddy reads the same copy of the book you do, and every passage it looks up ends before your current page. Searching the text, quoting it and summarizing it all stop at your bookmark. The model is also told, as its highest-priority rule, not to reveal anything beyond what it was given, even if it happens to know the book.

That is the difference from asking a general chatbot. It is not trying harder to keep a secret. For the book text, the secret never reaches it.

Try it with your own book

Open a DRM-free EPUB in BookBuddy, or connect your tolino account, read to wherever you are, and ask the question you were afraid to type into ChatGPT.