Most inaccurate thing I have heard all day.

If you paste a 1k line React component and ask a frontier model to add a feature or do some refactor, it will do a good job.

Paste 10k lines of code files - no chance it does it right the first try. It will start making all kinds of mistakes.

I use this stuff daily - I don’t care what they advertise here are the literal facts using the best models available today:

1 function = perfect

1k lines of code = good and works but probably not in the exact style you said

5k lines = stuff is getting omitted, assumptions are being made

10k lines = no chance it works

I use LLMs for coding every day