Anthropic Releases Claude Opus 5.5: Fable 5.1-Level Performance at 40% Lower Running Cost Than Opus 5

Anthropic has launched Claude Opus 5.5, the first model in the Claude 5.5 family. It delivers performance comparable to Claude Fable 5.1 on most tasks while costing 40% less to run than Opus 5. This model generates output 30% faster and shows improvements in safety and performance. On benchmarks, Opus 5.5 surpasses Fable 5.1 in agentic coding, knowledge work, and computer use, while matching Mythos 5.1 in biology and cybersecurity, utilizing safeguards similar to Fable 5.1.