Both are fine, though not frontier of course. They mostly take unwarranted shortcuts, trying to find the easiest way to reach the literal goal set by you, failing to see the broader picture. But they definitely do not confabulate, as in they don't just make up nonexistent things, they would rather walk extra mile to verify when they're not certain, which is the reason the software they make is trash but it works in the narrow sense. They can be rigid in their writing style do to mode collapse, but I haven't seen this leading to them inventing nonexistent functions or anything like that in a long while. RL makes them do all this, modern LLMs are very far from being next token predictors trained only on text.