PredictionArticle

Anthropic's original plan to remove Fable 5 from subscriptions was driven by compute capacity concerns, and they may need to dial back training to free up GPUs for serving the model.

The author speculates that compute constraints drove Anthropic's original restriction, and that now serving Fable 5 broadly could force Anthropic to divert GPUs away from training. ✦ AI generated

Simon Willison · Simon Willison's Weblog · 2026-07-18 · original ↗

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Their original plan was driven by concerns over compute capacity. I wonder if they'll have to dial back their training efforts in order to make more GPUs available to help serve the model.

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▦ Anthropic ✳ Claude Fable 5

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Evidence · 1

Anthropic may have held back its 'Mythos' model not out of safety altruism, but because it was too computationally expensive to serve — 10-20x the token cost of Opus — and they needed to save capacity for Opus 4.7 while turning the delay into a marketing event.Sacks · All-In Podcast · conf 85%

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supports → Anthropic may have held back its 'Mythos' model not out of safety altruism, but because it was too computationally expensive to serve — 10-20x the token cost of Opus — and they needed to save capacity for Opus 4.7 while turning the delay into a marketing event.Sacks · All-In Podcast