Initial Impressions of Claude Fable 5
Original: Initial impressions of Claude Fable 5
Simon Willison spends 5.5 hours with Claude Fable 5, finding it impressively knowledgeable but slow, expensive, and prone to triggering strict safety guardrails.
Anthropic released Claude Fable 5 and Claude Mythos 5 simultaneously; Fable 5 matches Mythos 5 in capability but adds strict safety classifiers, with new API fallback mechanisms for rejected requests. Both models offer 1M token context, 128K max output, January 2026 knowledge cutoff, priced at $10/$50 per million tokens — double Opus 4.x. Simon's knowledge-breadth test shows Fable 5 substantially outperforms Opus 4.8, listing dozens of his open-source projects with approximate dates from memory alone.
Simon Willison 在 Claude Fable 5 發布當天取得存取後，花了約 5.5 小時對其進行全面測試，並在部落格分享第一印象。
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