Anthropic launches Claude Sonnet 5, now default in Claude Code

Anthropic released Claude Sonnet 5 on June 30, positioning the model as a cheaper, faster way to run agentic and coding workloads while narrowing the gap with its flagship Opus tier. The model ships with a one-million-token context window and promotional API pricing of $2 per million input tokens and $10 per million output tokens through August 31, after which rates rise to $3 and $15. Sonnet 5 has become the default model in Claude Code for Free and Pro users as Anthropic pushes to win developer share against OpenAI.