[Bug] Degraded Claude model performance: Increased error rate and missing critical details

Bug Description
Claude has been unmistakeably poorly behaving this morning, missing critical elements that Opus 5.5 did not miss in the past several days, not checking on details. I feel it is about 20% less correct than normal despite my settings all being the same. This is my first bad report that I recall but I wanted to bring it to your attention because it is remarkably striking. I have not been using different prompting strategies, I'm not asking different questions. I'm not asking harder questions. I'm not overestimating claude's abilities from the last few days, something does seem different. This is the first time since Opus 5.5 release that I had to reach out to Fable to double check things.

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.283
• Feedback ID: 40823419-b577-4db4-b69e-fcd9e0ce3575

Errors

[]