Claude Fable 5 vs Claude Mythos 5: the same brain, two sets of guardrails
Here is the twist that confuses everyone: Claude Fable 5 and Claude Mythos 5 are the same underlying model, with the same specs and the same price. The only difference is a layer of safety classifiers - present on Fable 5, lifted on Mythos 5 - and who is allowed to use each. For almost everyone the answer is simply Fable 5. This article explains why the pair exists, exactly what the safeguards do, and how to build against them, for both curious readers and engineers.

