Anthropic Releases Claude Opus 5.5: Fable 5.1-Level Performance at 40% Lower Running Cost Than Opus 5
Anthropic has released Claude Opus 5.5, the first model in its new Claude 5.5 family. The team states it performs at the level of Claude Fable 5.1 on most work. It also costs 40% less to run than Opus 5 on typical workloads at default settings. On Anthropic’s own benchmarks, it leads in agentic coding, computer use, and knowledge work. Is it deployable? Yes, as a managed API model. Anthropic has not released weights, so self-hosting is not an option. Developers can call claude-opus-5-
Anthropic has released Claude Opus 5.5, a new language model that performs at the level of its previous Claude Fable 5.1 model while costing 40% less to run than the earlier Opus 5. The model is available through managed APIs on multiple platforms but not as downloadable weights for self-hosting. Opus 5.5 shows strong performance on coding and knowledge work benchmarks, with output generation over 30% faster than Opus 5, and early testers reported significant improvements on large-scale coding tasks like codebase migrations and audits. The model includes safety safeguards comparable to Fable 5.1, with restricted capabilities for cybersecurity and biology tasks that are either re-routed to an earlier model or limited to vetted organizations.
Explainer: Claude Fable 5.1 Explained: Price, Changes and the Ban Story
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