GoKawiilUsers report altered reasoning behavior in Anthropic's Claude Opus model since Nov 3
A user-submitted post claims that Anthropic's Claude Opus (referred to as 'Opus 5.5') began showing changed 'thinking patterns' starting November 3, with some users describing it as 'nerfed.' The post argues that the earlier common advice to set reasoning effort to 'high' for all tasks may no longer hold given this shift.