Anthropic Launches Claude Sonnet 5 With Near-Opus Performance at a Lower Price

Anthropic today introduced Claude Sonnet 5, a more affordable model that narrows the gap between Sonnet and Opus. Anthropic says Claude Sonnet 5 is its most agentic Sonnet model to date, able to make plans, use tools like browsers and terminals, and run autonomously.

Opus models have better agentic capabilities, but they're more expensive than Sonnet models. Sonnet 5's performance is similar to Opus 4.8, and it has improved over Sonnet 4.6 in areas including reasoning, tool use, coding, and knowledge work.

As for agentic capabilities, Sonnet 5 is able to finish complex tasks that Sonnet 4.6 could not complete, and it checks its own output without being asked. It is better at refusing malicious requests, and Anthropic says it shows lower rates of hallucination and sycophancy.

Sonnet 5 is available across all plans and is the default model for Free and Pro plans. It is priced at $2 per million input tokens and $10 per million output tokens through August 31, then prices will go up to $3 and $15, respectively.