Fable 5.1 First Impressions: High Pricing, Less Optimization, Shift to Complex Tasks

Aizkmusic · x · 2026-09-02

The author shares initial impressions of Anthropic's Fable 5.1, noting it is built for large, long-scale tasks rather than cost optimization. It feels designed for users with unlimited access rather than public efficiency. The author speculates that the Chinese pricing war pressures Anthropic to pivot towards difficult, non-CS fields like biology for competitive wins. In a 15-minute test, the model consumed $11 (exceeding a $10 budget) and spawned unrequested sub-agents. The author observes that frontier models are becoming increasingly similar on short tasks, making it harder to distinguish new releases by "vibe" alone compared to a year ago. While the 50% reduction in cache pricing is significant, it adds mental overhead to managing different model strategies.

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