🚀 Anthropic Introduces Claude Fable 5 and Mythos 5 Models
The company has released new flagship models, Claude Fable 5 and Claude Mythos 5, which are twice as expensive as the current top-tier Opus 4.8. The models support a 1 million token context window and feature Adaptive Thinking.
🌍 Anthropic is building a hierarchy: Sonnet (efficiency) → Opus (premium) → Fable (frontier), creating a segment of ultra-powerful AI agents. The introduction of stop_reason: "refusal" within a successful HTTP 200 response requires an update to response processing logic.
👤 Models for deep research and autonomous programming are now available, albeit at a high price. If accuracy is critical and token cost is not the deciding factor, Fable 5 will become the new standard.
Source 1: https://www.aipricing.guru/news/claude-fable-5-mythos-5-pricing-june-2026/