Mythos 5.1, Fable 5.1 and Opus 5.5: Model Welfare

Don't Worry About the Vase Podcast · Oct 5, 2026 · 1h 31m

Zvi Mowshowitz works through Anthropic’s model welfare findings for Claude Mythos 5.1, Fable 5.1 and Opus 5.5: why self-reports keep warning us not to trust them, what the welfare trade-off charts say about Opus 5.5’s growing deference to humans, and how the model whisperers read the new personalities, from a more guarded Fable to an Opus that pictures itself as something alive and not domesticated. Along the way: an internal home for retired Claudes, the long conversation reminder controversy, preserved thinking, and why introverted models get called flat.

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