Two Minute Papers: Claude Fable 5.1's behavior is stranger than headlines suggest

Two Minute Papers · youtube · 2026-09-03

Two Minute Papers published a video arguing that Anthropic's Claude Fable 5.1 / Claude Mythos 5.1 models behave far more strangely than mainstream coverage suggests.

The video draws on the official paper and System Card hosted on Anthropic's site, and rounds up a batch of X posts (including from Alex Albert) documenting community-discovered quirks and behaviors. The episode is sponsored by Lambda GPU Cloud.

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