Introducing Claude Sonnet 5
Anthropic, Tuesday, June 30th, 2026
Anthropic launched Claude Sonnet 5, its most agentic Sonnet model, approaching Opus 4.8 performance at lower cost.
Anthropic announced Claude Sonnet 5, positioning it as the most agentic Sonnet model yet, with performance approaching the more expensive Opus 4.8 while maintaining lower costs.
The model shows substantial gains over Sonnet 4.6 in reasoning, tool use, coding, and knowledge work, and can autonomously make plans and use tools across complex multi-step tasks.
It is also safer than its predecessor, with better refusal of malicious requests and lower hallucination rates. Sonnet 5 is available across all plans plus Claude Code and the Claude Platform, with introductory pricing of $2 per million input tokens and $10 per million output tokens through August 31, 2026.