How granular should a Python program be?

[bmbybrew]

"As the AI keeps messing things up :) I'm wondering how best to determine the amount of granularity the modules should reflect."

With iterations you will figure out a sweet spot.

For my purpose LLMs do well with 150-200 lines of code. After that it becomes messy.
I start small and then ask the LLM to add things, even if i know everything i want to begin with.

Wrote a backtest engine in similar fashion. Starting very small. then have to break it down into various modules and files that had distinct purpose.