Claude Fable 5.1 (Xhigh, Default Fallback)

Claude Fable 5.1 is an artificial intelligence model developed by Anthropic, released on September 1, 2026. This model features adaptive reasoning with high-effort processing and a default fallback configuration. In standardized testing, the model achieved an intelligence index of 64.8 and a coding index of 80.7, while its math index remains unknown. Benchmark performance results include a GPQA score of 0.934, an HLE score of 0.587, a SciCode score of 0.601, and an LCR score of 0.78. Regarding operational performance, the model maintains an output speed of 65.209 tokens per second with a time to first token of 24.21 seconds. Pricing is structured at $10.00 per million input tokens and $50.00 per million output tokens, resulting in a blended rate of $20.00 per million tokens.