The conventions even matched the rest of the framework, so it looked kosher and I had to do some searching to see if Claude had referenced an outdated or beta version of the docs. It hadn't - it just hallucinated the funcionality completely.
When I pointed that out, Claude quickly went down a rabbit-hole of writing some very bad code and trying to do some very unconventional things (modifying configuration code in a different part of the project that was not needed for the task at hand) to accomplish the goal. It was almost as if it were embarrassed and trying to rush toward an acceptable answer.
- Aha, the error clearly lies in X, because ... so X is fine, the real error is in Y ... so Y is working perfectly. The smoking gun: Z ...
- While you can do A, in practice it is almost never a good idea because ... which is why it's always best to do A
I worked with Grok 4.1 and it was awesome until it wasn't.
It told me to build something, just to tell me in the end that I could do it smaller and cheaper.
And that multiple times.
Best reply was the one that ended with something algong the lines of "I've built dozens of them!"