Anthropic released Claude Sonnet 5, its most agentic Sonnet model — able to plan and run autonomously with tools like browsers and terminals.

It delivers near-Opus 4.8 performance at a fraction of the cost — $2 / $10 per million input/output tokens at intro pricing through August 31.

Sonnet 5 is the new default on Free and Pro and is live across the API as claude-sonnet-5, with stronger safety than Sonnet 4.6.