Anthropic's Claude Sonnet 5 Makes Agents Cheaper

Anthropic has launched Claude Sonnet 5, a more powerful mid-tier model designed for agentic tasks like browser use, coding, and autonomous workflows. Priced at $2 per million input tokens and $10 per million output tokens through August 31, it undercuts rivals like OpenAI's GPT-5.5 and Google's Gemini 3.1 Pro. It becomes the default model for free and Pro plans starting Tuesday. Sonnet 5 delivers performance close to the pricier Opus 4.8, with improvements in reasoning, tool use, and knowledge work. It also shows lower rates of hallucination, sycophancy, and susceptibility to prompt-injection attacks than its predecessor, though it still trails Opus 4.8 on safety benchmarks.