Anthropic Claude Fable 5, the most powerful and most intelligent Claude model, a new tier above Opus. State-of-the-art deep reasoning, long-horizon autonomous work, and code understanding and generation, surpassing Opus 4.8 on the hardest analyses, large refactors, and complex system design. Supports very long context for whole-codebase or multi-document analysis. Premium pricing (about twice Opus 4.8); reserve it for the most demanding tasks and use Opus or Sonnet for daily work.