Across 16 shared benchmarks, Claude Fable 5.1 scores higher on 16 and o3 on 0. The widest gap is gdpval, where Claude Fable 5.1 scores 63.3 against 12.8. o3 is the cheaper of the two on tracked API pricing ($2.00 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.