Initial impressions of Claude Fable 5

Anthropic has launched the Claude Fable 5 model, which offers similar performance to Claude Mythos 5 but with stricter safety guardrails. The model features a one million token context window and a maximum output of 128,000 tokens, with a knowledge cut-off in January 2026. The pricing for the new model is set at double that of previous Claude Opus models, costing $10 per million input tokens and $50 per million output tokens. New mechanisms have been introduced to alert users when safety limits are reached, including an option for automatic fallback to another model if a request is rejected.