On Tuesday, Anthropic launched a new model, Claude Opus 5.5, designed to deliver high-end model performance at a lower cost. On the same day, the company announced a partnership with the medical knowledge platform OpenEvidence to provide AI tools that help physicians locate research and treatment guidelines, rolling them out for free in approximately 100 countries.
Anthropic stated that Opus 5.5 offers performance comparable to its top-tier model, Fable 5.1, while operating at a cost 40% lower than the previous generation. The company claims that in a software development test, Opus 5.5 outperformed OpenAI’s GPT-5.6 Sol while running at just about one-third of the latter’s cost.
Opus 5.5 is priced at $4 per million input tokens and $20 per million output tokens—20% lower than Opus 5. It is currently available on platforms such as Amazon Web Services (AWS), Google Cloud, and Microsoft Azure.
Anthropic also announced that Claude Sonnet 5.5 and Claude Haiku 5.5 will be released in the coming weeks.
This launch comes amidst intensifying debate regarding the risks associated with AI. Earlier this month, Anthropic CEO Dario Amodei called on the global AI industry to slow the pace of frontier model development in order to address safety concerns.
Anthropic stated that prior to its release, Opus 5.5 underwent testing by independent AI safety research groups Frontier Design and METR, incorporating safeguards previously reserved for the company’s most powerful systems.
Internal testing indicated that the likelihood of the new model attempting to bypass restrictions is approximately 85% lower than that of Opus 5 or Mythos 5.1.
Beyond model development, Anthropic has partnered with the medical knowledge platform OpenEvidence to expand access to an AI-powered clinical decision support tool—previously available for free to physicians in the U.S. and Europe—to approximately 100 additional countries, including Uganda, Angola, Sudan, Haiti, and Mongolia. This initiative aims to assist physicians in regions where access to medical literature, specialist resources, and continuing education is limited.
The two companies stated that Anthropic will provide backend technical support, while OpenEvidence will tailor the tools to local medical facilities and conditions. Financial terms of the partnership were not disclosed.
Ahmed Bendary, a cardiologist at Benha University in Egypt, noted that expanding the reach of such tools beyond the United States and Europe would be a major benefit for regions that struggle to afford subscriptions to major medical journals.