I was halfway through a mystery novel and couldn't remember who a minor character was. I searched for it. The first result spoiled the ending.

That's the whole origin story of LORE , an open-source reader that turns the books you own into a knowledge graph and answers questions about them with every sentence cited, and without spoiling anything past the chapter you're on.

This post is about how it works, and about the bugs that taught me the most.

Why not just ask ChatGPT?

You can ask a general chatbot about a famous book, and it'll answer from memory. That breaks down in three ways:

It can't cite. You get a confident paragraph and no way to check it.

It doesn't know your book. A less famous novel, a new release, or your own copy: it's guessing.

It has no idea where you are.…