Across 36 shared benchmarks, Claude Fable 5.1 scores higher on 35 and GPT-5.4 on 1. The widest gap is AA-Omniscience, where Claude Fable 5.1 scores 43.5 against 5.8. GPT-5.4 is the cheaper of the two on tracked API pricing ($2.50 against $10.00 per million input tokens).
Best tracked score per model per benchmark (default configuration; source-attributed). ↓ marks lower-is-better metrics. Open either model for its full surface, provenance and pricing. Quoted rates are the price-setter row we currently track for each model — its direct or vendor-official listing where one exists (anthropic-official, direct), otherwise the lowest tracked offer.