Karpathy Calls Claude Fable 5 a Major Step Forward for Long Tasks

Andrej Karpathy says Claude Fable 5 is the same underlying model as Mythos with added safeguards, and that it leads on nearly all benchmarks.

He describes it as a step change, especially for long, difficult problem-solving sessions where it handles more ambitious tasks without close supervision. He notes that its safeguards are set a bit too aggressively at launch and may be tuned over time.