Absolute typing smoothness
Absence of minor typos, broken grammar, or accidental repetitions typical of fast manual typing.
"After the core system update, we encountered an integration issue with the payment gateway. The bug was promptly resolved by rolling back the changes."
"After the core update, our integration with the payment gateway broke downed. We had to do an emergency rollback."
Traces of rewriting on the fly
A grammatical mismatch or an unnatural typo ("broke downed") occurs when a person started writing the phrase "broke down", changed their mind halfway through to write "failed", but accidentally mixed the suffixes. The fingers typed one thing, the brain switched to another, and the author didn't notice the discrepancy.
A model (LLM) statistically calculates token connections. For it, grammatical agreement and tenses are a strict mathematical law of a graph. It is simply incapable of generating a "motor typo" of this kind.