> it hallucinated a missing brace (my code parsed fine), "helpfully" inserted it, and then proceeded to break everything.
Your tone is rather hyperbolic here, making it sound like an extra brace resulted in a disaster. It didn't. It was easy to detect and easy to fix. Not a big deal.
It's not a big deal in the sense that it's easily reversed, but it is a big deal in that it means the tool is unpredictably unhelpful. Of the properties that good tools in my workflow possess, "unpredictably unhelpful" does not make the top 100.
When a tool starts confidently inserting random wrong code into my 100% correct code, there's not much more I need to see to know it's not a tool for me. That's less like a tool and more like a vandal. That's not something I need in my toolbox, and I'm certainly not going to replace my other tools with it.
Your tone is rather hyperbolic here, making it sound like an extra brace resulted in a disaster. It didn't. It was easy to detect and easy to fix. Not a big deal.