Sonnet 5.5: faster and cheaper improvement compared to Sonnet 5

The Sonnet 5.5 model was introduced and achieves better results than Sonnet 5 on numerous benchmarks, in some cases significantly. It is a faster and lower-cost alternative alongside Claude Opus 5.5, performing especially well on everyday, well-specified tasks, bug fixing, and creating nicely formatted documents, slide decks, and tables.