Claude Opus 5.5 Officially Lands on B.AI, API and Web Chat Simultaneously Open

Odaily reports that the B.AI platform has announced the official launch of Claude Opus 5.5, the first model in the Claude 5.5 series released by Anthropic, with simultaneous access now available via both API and Web Chat. The model is purpose-built for long-horizon agentic coding and complex knowledge work, matching Claude Fable 5.1 performance on most tasks while reducing operating costs by approximately 40% compared to Opus 5. It supports a 1M Token ultra-long context window and up to 128K output, and demonstrates leading capabilities in Computer Use and multi-step automation scenarios. Starting today, developers and users can directly access Claude Opus 5.5 through the B.AI platform.