ContextArticle

Anthropic restricted Fable access due to compute constraints, wanting clearer visibility into demand and compute availability before committing to keeping the new model cheap for subscribers.

The author explains Anthropic's original reasoning for limiting Fable access was uncertainty about compute capacity and demand. ✦ AI generated

Author · Simon Willison's Weblog · 2026-07-12 · original ↗

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Anthropic's original rationale for this was compute constraints - they wanted a better idea of both demand and compute availability before committing to keeping the new model cheap for subscribers.

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▦ Anthropic ✳ Fable

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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 provides context → Anthropic is extending Claude Fable 5 access on all paid plans, along with the 50% higher Claude Code weekly rate limits, through July 19.Anthropic · Simon Willison's Weblog explains mechanism → Users can spend up to half their weekly usage limit on Fable 5, then either pay with usage credits or switch to another model to stay within their remaining limits.Anthropic · Simon Willison's Weblog provides context → Anthropic should make Fable permanently available on paid plans instead of continuing to extend temporary cutoff dates.Author · Simon Willison's Weblog