Anthropic released its new Claude Opus 5.5 AI model, stating it performs similarly to Claude Fable 5.1 on most tasks, but at a significantly lower price. Announced Tuesday, September 22, Opus 5.5 is the first in the Claude 5.5 family. Anthropic claims Opus 5.5 costs about 40 percent less to operate on typical workloads than Opus 5, which launched in July. Claude Sonnet 5.5 and Claude Haiku 5.5 models are expected in coming weeks.
Anthropic reports Opus 5.5 leads its benchmarks in agentic coding, computer use, and knowledge work. On GDPval AA v2.1, Opus 5.5 scored 1,846, surpassing Fable 5.1 at 1,735 and Opus 5 at 1,708. For Terminal Bench 4.0, Opus 5.5 achieved 66.4 percent, compared to OpenAI's GPT 6 Astra at 57.9 percent. Astra led on some tests, including Terminal Bench Science 0.1. Anthropic also cautioned that benchmark margins are less reliable at this level of capability.