Anthropic launches Claude Sonnet 5, a cheaper agent model



Anthropic has launched Claude Sonnet 5, its most agentic mid-tier model yet. It runs close to the flagship Opus 4.8 on many tasks, but costs less than half as much.

Anthropic said on June 30, 2026 that Sonnet 5 is available today across every plan. The company built it to act, not just answer. It can make plans, drive browsers and terminals, and run on its own for long stretches. That kind of work needed bigger, pricier models only a few months ago.

The pitch is simple. Sonnet 5 offers near-flagship performance at a mid-tier price. It lands close to Opus 4.8, Anthropic’s most capable model, on reasoning, tool use, coding, and knowledge work. It clearly beats its predecessor, Sonnet 4.6. And it costs far less than Opus to run.

Cheaper agents, on purpose

Price sits at the centre of this launch. Sonnet 5 starts at $2 per million input tokens and $10 per million output tokens. That introductory rate holds until August 31, 2026. After that it moves to $3 and $15. Opus 4.8, by contrast, costs $5 and $25. TechCrunch framed the model as a cheaper way to run agents, and that is the point.

The timing matters. Companies rushed to deploy AI agents, then recoiled at the bills. Agents loop, call tools, and burn tokens fast. A model that gets close to Opus quality for a fraction of the cost speaks directly to that pain. It also speaks to a market hunting for savings after enterprise AI bills ballooned.

There is a catch in the small print. Sonnet 5 uses a new tokenizer, so the same text can map to up to 1.35 times more tokens than before. Anthropic set the introductory price so the switch stays roughly cost-neutral. The headline rate looks low, but the token count can climb.

How good is it?

On Anthropic’s own benchmarks, Sonnet 5 marks a clear step up from 4.6 without quite catching Opus. On an agentic coding test it scored 63.2 per cent, against 69.2 per cent for Opus 4.8 and 58.1 per cent for Sonnet 4.6, according to early reporting. On one knowledge-work benchmark it edged ahead of Opus. Anthropic also offers an “effort” dial, letting developers trade cost for accuracy between the two models.

Early testers told Anthropic the model finishes complex jobs where older Sonnets gave up, and that it checks its own output without being asked. Those claims come from the company’s launch material, so they deserve the usual caution. Independent testing will tell the real story.

Safer, with a cyber caveat

Anthropic says Sonnet 5 behaves better than 4.6 on safety. It refuses malicious requests more often and resists prompt-injection attacks, where hidden instructions try to hijack an agent. It also hallucinates and flatters less. On an automated audit of misaligned behaviour, it scored safer than 4.6, though worse than Opus 4.8 and the Mythos preview.

Cybersecurity is the sharper point. Anthropic did not train Sonnet 5 for cyber tasks, and it performs poorly at building software exploits. In a test run with Mozilla on the Firefox browser, the model never produced a working exploit. Even so, Anthropic shipped it with real-time cyber safeguards on by default, the same ones used on Opus 4.7 and 4.8. Those guardrails stay lighter than the ones around Fable 5, its locked-down public model.

A discount with a strategy behind it

The low price is not charity. Anthropic is racing rivals for developers, and a capable, affordable agent model is how you win them. The company also writes much of its own code with Claude, so a better, cheaper Sonnet helps its own engineers too. It is also moving toward a planned public listing, where revenue growth and developer reach both count.

The wider context is cost. Running agents around the clock can rack up eye-watering bills, and Anthropic has set out ambitious revenue targets to fund its model work. Sonnet 5 is its answer to both. Push capability down the price curve, keep developers inside the ecosystem, and let the effort dial handle the rest.

Claude Sonnet 5 is live now in Claude’s apps, Claude Code, and the API, with higher rate limits across the board. For most developers, the question is no longer whether the model is clever enough. It is whether it is cheap enough to run all day. Anthropic is betting the answer is finally yes.



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ZDNET’s key takeaways

  • Staff who use AI can end up with more to do, not less.
  • Think carefully about the tools you’re using and why.
  • Adopt a set of standards and refine your outputs.

The promise of productivity boosts from AI can come with an unwelcome side order of stress. Harvard Business Review found that AI doesn’t reduce work; it intensifies it, leading to cognitive fatigue and unsustainable hours.

While the common perception is that AI can help reduce workloads, allowing employees to focus more on higher-value and more engaging tasks, HBR’s research found that staff using AI worked more quickly and often ended up with more to do, not less.

Also: Forget productivity: Here are 5 strategic shifts that drive real AI value

While we’ve written about how some professionals are finding ways to turn AI’s time-saving magic into a productivity superpower, we’ve also recognized that some employees have started to become tired with the low quality of AI outputs.

Ankur Anand, group CIO at tech recruiter Harvey Nash, said professionals who want to avoid cognitive fatigue must understand how to use AI effectively and its potential risks.

“That focus will help to reduce the noise around the workload that AI creates,” he told ZDNET, suggesting that many people have unrealistic expectations about the productivity boost that AI will provide.

Also: Why I ditched Copilot for Claude in Word, Excel, and PowerPoint – and how you can, too

“Many organizations are telling their people, ‘We want to understand how you’re making an impact with AI,'” he said. “But these professionals are not empowered, which means that using AI adds a lot of pressure, because they need to prove themselves on their own terms.”

If you’re going to make the most of AI at work, then you’re going to have to find an effective balance between completing tasks quickly and producing high-quality work. 

Here’s how the experts believe professionals can ensure they reap the benefits, not the problems, of AI — and they suggest that you’ll need to focus on three core areas: tools, guidelines, and outputs.

Limit your toolset

Alex Read, senior enterprise product manager for data at energy provider EDF UK, told ZDNET that the best way for professionals to reap the benefits, not the challenges, of AI is to be uber-focused on tools that help you produce value in your roles.

While there are thousands of potential AI-enabled services on the market, Read said sensible professionals limit their horizons.

Also: How this travel company’s AI rollout drove a 73% satisfaction boost: A 5-step playbook for your business

In his own role, for example, Read focuses on how AI can help him build a data platform and update information accurately, efficiently, and productively: “Anything outside of that scope is noise for me.”

That sentiment resonated with Nick Pearson, CIO at technology specialist Ricoh Europe, who told ZDNET it’s important to take a step back and think carefully about how an AI tool can help you produce value in your role.

“If you think about the phrase ‘gen AI,’ the tech is very good, by definition, at generating outputs,” he said. “I could go to bed in the evening, set the model to work, and we could have four new IT strategies produced overnight.”

Also: Worried AI agents will replace you? 5 ways you can turn anxiety into action at work

However, quantity doesn’t necessarily mean quality. Pearson suggested it’s important to focus on AI’s blind spots, particularly as most models are trained on preexisting content.

“AI can’t inspire people, per se; it can’t naturally create something new, because it’s actually quite recursive,” he said.

“And the judgment you have to put in sometimes, on top of everything else, whether it be an ethical or a capability judgment, is not there automatically in the technology.”

It’s in this gap, said Pearson, that human experts play a critical role: “We’re toying with that concern as an organization and saying, ‘Where does AI really play an important role, versus where are we upskilling people in areas that AI probably won’t play for a long time?'”

Work to the guidelines

HBR’s research found that an initial productivity surge when AI is adopted can lead to lower-quality work, turnover, and other problems as people work harder rather than smarter.

To correct this issue, HBR said companies need to adopt an “AI practice,” or a set of norms and standards around AI use that help professionals ensure they use AI in a constrained but productive manner.

Also: 90% of AI projects fail – here are 3 ways to ensure yours doesn’t

At EDF UK, Read is part of an internal AI Center of Excellence in enterprise IT, which enables policy for the effective use of AI across the wider organization. 

In addition to Read, who contributes input from a data-use perspective, the group includes other tech representatives, such as the firm’s senior manager of AI, principal software engineer, and principal solution architect.

“The remit of this center is to make sure that, when the federated business units are looking to build, develop, and deploy AI services, they have platforms, guidance, best practices, architectural assets, and materials to guide them on how to safely and efficiently adopt AI and operationalize it at scale,” he said.

Some of the key themes the center considers when assessing AI tools are scalability and reusability, ensuring a proposed service doesn’t replicate one already in use.

Also: 5 ways to use AI when your budget is tight

“All new tools and services related to AI will go through that hopper and funnel to understand scope and ensure the security, regulatory, and ethical side of things are understood,” he said, suggesting that all professionals should use their organization’s pre-existing guidelines to foster an appropriate exploitation of emerging tech.

“The benefit that guided approach brings is that it allows us to be clear in our messaging around what AI services can be used, how they’re used from a use-case perspective, and ultimately, what personas are allowed to use them.”

Refine your outputs

Even when tools are assessed and considered acceptable, there can still be an overreliance on AI outputs. Worse, some professionals can drown in the insights they receive, leading to higher stress and fewer benefits.

Louise Newbury-Smith, head of UK&I at technology specialist Zoom, told ZDNET that one way to ensure your outputs are constrained is to focus on prompting.

“Use simple amendments to be specific, such as ‘Give me the top three things with the biggest impact.’ That approach should guide your prompt, rather than saying, ‘Give me everything you know about this topic.'”

Also: 5 ways to fortify your network against the new speed of AI attacks

Newbury-Smith said the successful use of AI is all about being smart about how it’s exploited, and that effectiveness comes down to enablement and engagement. If a prompt yields too much information, refine it until you get what you need. She said this should still be faster than trying to get answers without AI.

The basic message for professionals is that effective applications of AI are all about you staying in the loop, said Bernhard Seiser, vice president of digital, data, and IT at AOP Health.

Think before you use AI, and think again before you push your outputs around the organization.

“It doesn’t help the business if you get AI-generated emails that are many pages long, and then you need ChatGPT to summarize the text,” he told ZDNET.

Seiser said that while there are certain tasks generative AI is good at and worth using for, in the end, “you need to use your brain.”





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