Anthropic Releases Claude Opus 5.5: Fable 5.1-Level Performance at 40% Lower Running Cost Than Opus 5
Anthropic released Claude Opus 5.5, matching Fable 5.1 on most work at about 40% lower cost.
Anthropic released Claude Opus 5.5, the first Claude 5.5 model, as closed-weight API claude-opus-5-5 on the Claude Platform, AWS, Google Cloud, and Azure. It says the model matches Claude Fable 5.1 on most work, runs about 40% cheaper than Opus 5, and prices tokens at $4 input and $20 output per million, with cache reads at $0.20. Reported scores include Terminal-Bench 4.0 at 66.4% and OSWorld 2.0 at 81.8%; GPT-6 Astra still leads Terminal-Bench-Science and AutomationBench. Cyber and biology requests use Fable 5.1-class safeguards, thinking cannot be disabled, and outputs carry EU AI Act watermarking.
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