Anthropic launched Claude Opus 5.5 on 22 September, the first model in its Claude 5.5 family. It says Opus 5.5 matches Fable 5.1 on most work and costs 40% less to run than Opus 5 on typical workloads, with API pricing cut to $4 per million input tokens and $20 per million output. Output is more than 30% faster too. It's the company's first release since Dario Amodei called for pacing the frontier, and plenty of people have pointed at the gap between the essay and the launch. Anthropic's answer is that METR and Frontier Design evaluated the model before release. Sonnet 5.5 and Haiku 5.5 follow within weeks. Teams building on Claude should redo their cost models. Opus-class work on typical workloads is now 40% cheaper.
