Anthropic launches Claude Opus 5.5, promising Fable-level performance at a lower price

Anthropic has released Claude Opus 5.5, a new AI model the company says performs at roughly the same level as its Claude Fable 5.1 model on most work, but at a significantly lower cost.

The model, announced on Tuesday, Sept.

22, is the first in Anthropic's new Claude 5.5 family.

According to the company's announcement , Opus 5.5 costs about 40 percent less to run on typical workloads than Opus 5, which launched in July.

Anthropic said Claude Sonnet 5.5 and Claude Haiku 5.5 will follow in the coming weeks.

Opus 5.5 is also the first new Anthropic model since CEO Dario Amodei called on AI companies to "pace the frontier" and put the brakes on AI development for safety reasons.

Claude Opus 5.5 leads in coding and knowledge work, Anthropic says Anthropic said Opus 5.5 leads its benchmark suite in agentic coding, computer use, and knowledge work.

On GDPval-AA v2.1, which tests real-world work across 44 occupations, the company reported that Opus 5.5 scored 1,846.

Fable 5.1 scored 1,735 and Opus 5 scored 1,708.

Credit: Anthropic / Mashable screenshot On Terminal-Bench 4.0, Anthropic reported Opus 5.5 at 66.4 percent, compared with 57.9 percent for OpenAI's GPT-6 Astra, which launched earlier this month .

Astra still led on some tests.

Those included Terminal-Bench-Science 0.1, on which it scored 64.6 percent, compared to Opus 5.5's 58.7 percent.

Anthropic also cautioned that benchmark margins have become a less reliable guide at this level of capability.

The company said the real-world gap between Opus 5.5 and Fable 5.1 is narrower than the scores suggest.