Oh, it just uses OpenAI.
https://github.com/steven-tey/novel/blob/62d32be43dae8aa40fa...
...and has a 50-request limit per day.
https://github.com/steven-tey/novel/blob/62d32be43dae8aa40fa...
...and trims the content to, um. 500 characters?!
https://github.com/steven-tey/novel/blob/62d32be43dae8aa40fa...
So past a certain point you'll get the same completion repeatedly / a completion of the start of your document, cut off.