s you've read (this is your "context window"). You might be able to follow the story, but if there's a crucial clue on page 21, you've already forgotten it. This is the problem that large language models face - they can only consider a certain amount of text at once.

Now, imagine if you had a magical bookmark that could summarize the previous chapters for you, condensing them into the space of a few pages. This way, even though you can still only remember the last 20 pages, you now have access to the impor