I have to say that 18 months ago I was incredibly impressed with how well Opus and Sonnet worked and I annihilated so much tech debt with controlled usage of both models in certain areas of our infrastructure. We're so far down the path of model decay now though that Opus 5.5 is borderline not usable for anything important. I can't be the only person using this bullshit that hasn't noticed how poorly the frontier models are performing in late 2026. #llm #claude #anthropic #ai