Anthropic has released Claude Opus 5.5, the first model in its new 5.5 series, delivering performance comparable to Claude Fable 5.1 while reducing operating costs by approximately 40% and boosting inference speed by over 30%. The model features significant improvements in agentic coding, computer use, and knowledge work tasks. Opus 5.5 is Anthropic's first release following its call to slow the frontier model race and has undergone external testing by METR and Frontier Design. The company reports the model achieved its best results to date on internal alignment evaluations. Concurrently, Anthropic has increased five-hour usage limits for Pro, Max, and Team subscriptions and introduced a one-time rate limit reset option for subscribers.