What is the best tool/setup to use an LLM to actively work on a text document real time, like cursor.ai does for code? 

The workflow I’d like is closer to “colleague commenting + making suggestions in your google docs” than copy/pasting a bunch of stuff back and forth.

https://lex.page/ 

i haven't used it myself so can't speak to its quality, but believe that is what it's going for

+1 to lex for editing features with decent llm but AI not comparable to solomode across notebooklm or openai canvas