Yes, you'd need to specify the subject of the sentence as you did in your second example.
My rule for students is basically, "If you have the option to be re-specify the thing you're talking about, do it." That's a solid rule for standardized tests, and usually applies to everyday writing (I'll caveat that this rule clashes with "the simplest answer is the right answer", so it is dependent on the actual sentence rather than an "all-or-nothing" rule).
Other common mistakes are those you hear about in middle-school (that's not a knock on anyone; rather, I say that to prove how long-ago it was that most of us ever reviewed common grammar and writing rules):
"Let's eat, Grandma!" vs. "Let's eat Grandma!"
Tying this back to GPT, I've read (and seen) folks write without any punctuation whatsoever. I can't speak to how GPT truly handles that, but if it's anything like "normal writing" and understanding, then punctuation is hugely important.
In my experience GPT-4 does much better at handling sentences without punctuation than most people do. I think this is because as a human we might start to interpret something a certain way before we get to the end of the (possibly punctuationless) sentence and then we get stuck a bit where it's hard to adjust... but GPT-4 is trying to generate something based on probability, and all of the wrong interpretations that we might get stuck on are less probable than the proper interpretation (on average). Of course this is just my pourquoi story and I haven't done any actual tests.
My rule for students is basically, "If you have the option to be re-specify the thing you're talking about, do it." That's a solid rule for standardized tests, and usually applies to everyday writing (I'll caveat that this rule clashes with "the simplest answer is the right answer", so it is dependent on the actual sentence rather than an "all-or-nothing" rule).
Other common mistakes are those you hear about in middle-school (that's not a knock on anyone; rather, I say that to prove how long-ago it was that most of us ever reviewed common grammar and writing rules):
"Let's eat, Grandma!" vs. "Let's eat Grandma!"
Tying this back to GPT, I've read (and seen) folks write without any punctuation whatsoever. I can't speak to how GPT truly handles that, but if it's anything like "normal writing" and understanding, then punctuation is hugely important.