Anthropic has released Fable 5.1, a new model iteration that introduces significantly lower pricing for cache reads and more permissive safety filters compared to its predecessor.
- Cache read prices are reduced from $1 to $0.25 per million tokens, lowering typical Claude Code session costs by up to 38%.
- Biology safeguards intervene on benign requests 85% less often than in Fable 5, with cyber interventions reduced by approximately 60%.
- The model features improved writing quality and tone, with active efforts to reduce "Claude-speak" and better handling of mistakes.
- Early feedback indicates strong performance in coding, data analysis, and agentic work, though the article notes GPT-6 Astra is also a competitive release.
The update aims to provide a more cost-effective and less restrictive experience for enterprise and API users while maintaining high capabilities across multiple domains.