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.
Popular Stories
Anthropic today updated its usage policy (via The Verge) to bar users from subjecting Claude to "sustained and needless abusive or cruel behavior."
Anthropic says the abuse rule is meant to apply only in extreme cases, where users "repeatedly act cruelly" toward the AI models with "no discernible purpose." The rule does not apply to ordinary user frustration, pushback, dark creative themes,...
Anthropic today introduced Claude Duet, its answer to Meta's Muse agent and OpenAI's Dots agent. Like Dots and Muse, it is a proactive agent that "reaches out before you ask."
Claude Duet connects to your apps and suggests things that need your attention. It completes tasks and can work in the cloud without local access to a computer. As with Muse and Dots, Duet has a virtual machine with...
Anthropic today launched Claude Opus 5.5, which it says is the first model in a new 5.5 model family. Opus 5.5 performs at the level of Claude Fable 5.1 on most work, but costs 40 percent less to run than Opus 5.
According to Anthropic, Opus 5.5 is a "major step up" from Opus 5 with improvements in performance and safety. Opus 5.5 is comparable to Mythos 5.1 in biology and cybersecurity, so...