Impossible to know unless you did read.

TL;DR works because I can see the length at a glance

And you cannot tell all AI. Only mainstream crap like ChatGPT and Gemini which is full of cached tropes and boilerplate formats so it all sounds the same.

My custom invoicing software automates notes based on years of my previous notes and tasks I did - looks nothing like AI.

Use a real library and local model, mess with settings, there is a lot more to this than the mainstream consumer apps.

So? This is about ovious stuff where you notice the typical annoying AI style directly in the first paragraph. After all, 99% of "regular" people use the mainstream models, and anyone who uses a local model probably knows enough about AI that they don't dump raw output on you.