Very cool. I've no idea if this is possible without rooting the Kindle, but I wonder would it be possible to highlight sections of text in a book and send it to something like this with a request to summarise/explain?
It's a good idea! Amazon doesn't offer an API for fetching highlights but services like Readwise seem to get around this by using a Chrome extension to do it. Not sure how that could be done on a Kindle though...