Claude Sonnet 4 degraded performance quality

Yesterday, I was thinking "is it just me or did this get way dumber than it was yesterday?"

Turns out: nope, Claude Sonnet regressed and got significantly dumber. The internet, obviously, assumed dastardly intent from Antrhopic. But they reckon "nope, we messed up - sorry about that, but hey - stuff happens".

It's kind of scary how Anthropic makes a change that makes the model dumber and my knee-jerk reaction is "What am I doing wrong? Am I getting dumber?".

And their response doesn't exactly inspire confidence either.