Anthropic releases Claude Sonnet 5, sets as default model

Anthropic released Claude Sonnet 5 on June 30, making it the default model for all Free and Pro users on July 1. Sonnet 5 introduces Adaptive Thinking and removes sampling parameters like temperature. It launched at a promotional price of $2/$10 per million tokens (reverting to $3/$15 after August 31), delivering approximately 93% of Opus 4.8 performance, making it the best-value flagship model on the market.