Claude Mythos Preview Posts 2x the Time Horizon of Any Competing Model

An early snapshot of Anthropic's Claude Mythos shows it sustaining coherent reasoning over task horizons more than double the next best model — a benchmark result that, if it holds, redefines what 'long-context' means for agents.

Anthropic's Alex Albert shared an early benchmark snapshot of Claude Mythos Preview, and the headline number is striking: the model reportedly sustains coherent task execution over a time horizon more than 2x that of the next best model, as @alexalbert__ posted. The tweet went viral across AI circles, and for good reason — extended reasoning horizons are the single biggest bottleneck preventing AI agents from handling real-world workflows that unfold over hours or days rather than seconds.

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