Anthropic launches Claude Sonnet 5, a mid-tier AI model built for affordable autonomous agents

Anthropic launches Claude Sonnet 5, a cheaper agent model

Sonnet 5 is Anthropic's most agentic mid-tier model yet, landing close to Opus 4.8 on reasoning, coding, and tool use, and starting at $2 per million input tokens. The strategy: make running agents cheap enough to do all day. 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.

Anthropic Wants You to Know Its New AI Model Is Definitely Not Too Dangerous to Release

AI developers today face a dual challenge: build state-of-the-art models that deliver big benefits at the lowest possible cost, and do so in a way that you won't attract the ire of the federal government. Anthropic -- which knows that ire better than any other company in Silicon Valley -- has tried to thread that two-eyed needle with its latest model, Claude Sonnet 5. Released on Tuesday, the new model is designed to balance agentic capability with frugality. Its performance across a suite of benchmarks is comparable to the more powerful Opus 4.8, but with a smaller price tag: When accessed through Claude Code, Sonnet 5 costs $2 per million input tokens and $10 per million output tokens -- less than half the price of Opus 4.8. Sonnet 5 "can make plans, use tools like browsers and terminals, and run autonomously at a level that, just a few months ago, required larger and more expensive models," Anthropic wrote in its announcement. Sonnet 5 is now the default model on Claude's free and Pro tiers, and also available to Max, Team, and Enterprise subscribers. It arrives at a time when tech developers have been facing mounting pressure to provide customers with cheaper AI tools. That's largely been driven by the proliferation of so-called AI agents throughout the business world, which can autonomously handle complex tasks over relatively long time horizons. They therefore tend to gobble up many more tokens -- the basic unit measuring AI usage -- than more limited systems, like a chatbot trained only to, say, field customer service questions. Both Anthropic and OpenAI have reportedly been considering big price cuts in order to attract new users, and keep current ones. Dumbed-down cybersecurity capabilities Anthropic's new announcement was also notable, however, for what it says Sonnet 5 can't do. Specifically, the company wrote that Sonnet 5 "shows substantially poorer performance" on cybersecurity-related tasks than Opus 4.8 and Mythos 5, the latter being one of the two models -- along with Fable -- which Anthropic took offline earlier this month following an opaque order from the federal government. When an AI developer underscores what a new model can't do, it's typically for safety reasons (as in, Our model won't respond to requests to generate realistic images of real people, or provide recipes for bioweapons). That's also the case with Anthropic's new model announcement -- the company has gone to great lengths to position itself as the leading voice of safety in the AI industry -- but it's more than likely for political reasons, too. Concerns around cybersecurity have very much been at the heart of Anthropic's latest snafu with the federal government. That's the official line from the Trump administration, at least, though plenty of others have floated the idea that ideological differences and personality clashes between the two parties have also played a role. Anthropic's Mythos model, which was first unveiled in April, was said to be so good at finding cybersecurity vulnerabilities in software that the company opted for a phased-out release among trusted partners. One of those was the National Security Agency (NSA), whose supposedly iron-clad cybersecurity systems were no match for Mythos. Crucially, however, the model didn't bypass the NSA's security systems; it just identified flaws in them. Fable 5 was released to the public with safety guardrails so stringent that many users found the model to be almost unusable. But after being led to believe that the model could be subjected to a jailbreak (i.e., prompted to bypass its own security guardrails) by Amazon CEO Andy Jassy, the government deemed it a national security risk. Anthropic seems intent to avoid another altercation with the federal government following the release of its newest model. "We did not deliberately train Sonnet 5 on cybersecurity tasks," the company wrote in it's announcement. The company added that although Sonnet 5 had shown "partial success" in developing a working cybersecurity exploit targeting Mozilla's Firefox browser, that was "likely due to improvements in general intelligence rather than specific training."

Anthropic upgrades Claude with new Sonnet 5 model, details here

Anthropic is upgrading Claude Sonnet, replacing Sonnet 4.6 from February with Sonnet 5 as the best medium-sized model. Claude Sonnet 5 has arrived In Anthropic's universe, Sonnet is Claude's medium-sized AI model that sits between the smaller Haiku model and the larger Opus model. Anthropic describes what's new with its latest model here. "Claude Sonnet 5 is built to be the most agentic Sonnet model yet. It can make plans, use tools like browsers and terminals, and run autonomously at a level that, just a few months ago, required larger and more expensive models," the company says. "Sonnet 5 narrows the gap: its performance is close to that of Opus 4.8, but at lower prices. It's a substantial improvement over its predecessor, Sonnet 4.6, on important aspects of agentic performance like reasoning, tool use, coding, and knowledge work." Pricing details are as follows: Claude Sonnet 5 is available everywhere today at an introductory price of $2 per million input tokens and $10 per million output tokens through August 31, 2026. It then moves to standard pricing at $3 per million input tokens and $15 per million output tokens. We've increased rate limits across Chat, Cowork, Claude Code, and the Claude Platform to accommodate the higher token usage of higher effort levels; users can select whichever level makes sense for their particular project. Anthropic also has its most capable Mythos 5 and Fable 5 models. Mythos 5 has fewer guardrails for select security researchers and platform owners. Fable 5 is the safer version that was briefly available for customers before being blocked by the U.S. government. Anthropic says it's working on restoring access in the future. Claude Opus 4.8 arrived at the end of May. Claude Fable 5 followed a few days later before being pulled. Mythos 5 has partially been restored to select customers. Claude Sonnet 5 arrives four months after the previous Sonnet 4.6 release. You can learn more about Claude Sonnet 5 here.

Anthropic debuts Claude Sonnet 5 for everyday agent tasks with lower cyber risk

Why it matters: The company says Sonnet 5 can handle autonomous tasks -- including browser use, planning, coding and knowledge work -- while posing fewer dangerous-cyber risks than its Opus and Mythos models. Zoom in: Anthropic says Sonnet 5 approaches performance of Opus 4.8, its most advanced widely available model, while Mythos and Fable are still restricted. * Sonnet 5 was not deliberately trained on cybersecurity tasks and has a "much lower ability" to perform any dangerous cyber activities than Anthropic's current Opus models. * Anthropic is in ongoing discussions with the Trump administration over their models and those talks include the release of Sonnet 5. The intrigue: The next generation Sonnet class model arrives while Anthropic is still waiting for government approval to restore full access to its most powerful models. * Mythos is now available on a limited basis and Fable 5 is on track to return soon, a source tells Axios. * This comes after the government abruptly asked Anthropic to take down these models over security concerns. * The administration also asked OpenAI to stagger the release of its most powerful class of models, GPT-5.6. Between the lines: Anthropic -- like OpenAI -- is betting that its coveted enterprise users will soon use AI less for chat and more for delegating tasks to agents. * Last week, OpenAI released data with Columbia, Duke and the University of Pennsylvania showing that non-developers are the fastest-growing user group for its agentic work tool, Codex. Follow the money: Sonnet 5 becomes the default model for all Claude Free and Pro users today, and is also available to Max, Team and Enterprise customers. * The company says the model delivers performance approaching Opus 4.8 at a lower price, giving developers a cheaper option for many coding and agentic workloads. * This comes amid a renewed focus around AI usage costs that's led some companies and developers to pivot to cheaper Chinese models. The bottom line: The AI labs are still releasing models as the administration figures out which to allow and which to limit.

Anthropic launches Claude Sonnet 5 at a steep discount to its top model as the company races toward a blockbuster IPO

Anthropic today released Claude Sonnet 5, a new AI model that the company says delivers near-flagship performance at mid-tier prices -- a move designed to give cost-conscious enterprise developers access to powerful agentic capabilities just as the San Francisco-based AI lab barrels toward an initial public offering that will test whether the private market's staggering AI valuations can survive public scrutiny. The release, which Anthropic describes as "the most agentic Sonnet model yet," makes Sonnet 5 the default model for users on Anthropic's Free and Pro plans, while also making it available to Max, Team, and Enterprise customers. Introductory API pricing is set at $2 per million input tokens and $10 per million output tokens through August 31, after which it rises to $3 and $15 respectively -- still well below the $5 input and $25 output pricing of Anthropic's top-of-the-line Opus 4.8. The strategic logic is unmistakable: Anthropic is trying to democratize access to capabilities that until very recently only its most expensive models could deliver, while building the kind of broad-based developer adoption that will look attractive in an S-1 filing. Sonnet 5 benchmarks show the mid-tier model closing in on Anthropic's flagship Opus Sonnet 5 posts major gains over its predecessor, Sonnet 4.6, across every evaluation Anthropic disclosed. On SWE-bench Pro, an agentic coding benchmark, Sonnet 5 scores 63.2% compared with Sonnet 4.6's 58.1% -- a jump that brings it within striking distance of Opus 4.8's 69.2%. On Terminal-Bench 2.1, another coding evaluation, the gap narrows further: 80.4% for Sonnet 5 versus 67.0% for Sonnet 4.6 and 82.7% for Opus 4.8. In multidisciplinary reasoning, as measured by Humanity's Last Exam, Sonnet 5 scores 43.2% without tools and 57.4% with tools -- the latter figure essentially matching Opus 4.8's 57.9%. On computer use tasks evaluated through OSWorld-Verified, Sonnet 5 reaches 81.2%, up from 78.5%. And on GDPval-AA v2, a knowledge-work benchmark, it scores 1,618 -- surpassing Opus 4.8's 1,615 and far exceeding Sonnet 4.6's 1,395. The pattern across these evaluations tells a consistent story: Sonnet 5 doesn't merely inch forward from its predecessor. It vaults into a performance tier that overlaps substantially with Anthropic's flagship model, while costing roughly 60% less per token at standard pricing and even less during the introductory period. Enterprise partners say Sonnet 5's agentic AI capabilities finish jobs that previous models abandoned The emphasis on agentic capabilities -- the ability to plan, use tools like browsers and terminals, and execute multi-step workflows autonomously -- reflects where the AI industry's center of gravity has shifted in 2026. Enterprises are no longer simply asking chatbots questions; they are deploying AI systems that can navigate complex software environments, execute multi-step coding tasks, and operate with minimal human supervision. Early access partners painted a picture of a model that doesn't just start tasks but finishes them. Sualeh Asif, co-founder of Cursor, the AI-powered code editor that has become a bellwether for developer tool adoption, said that "with Claude Sonnet 5, agents stay on plan, follow our conventions, and ship clean multi-step changes, all at an efficient cost." Daniel Shepard, a senior engineer at Zapier, described handing the model a two-part automation job -- updating Salesforce account tiers and sending a launch announcement -- that "used to stall halfway" with previous models but now completes end to end. These testimonials matter because they describe exactly the kind of reliability gap that has kept many enterprises from moving agentic AI from pilot programs to production deployments. A model that gets 80% of the way through a complex task before stalling creates more problems than it solves; one that reliably completes the full workflow changes the economics of automation. Anthropic also introduced cost-performance curves showing that developers can now adjust effort levels across Sonnet 5 and Opus 4.8 to find the optimal balance of cost and accuracy for their specific use case -- a granularity that reflects growing sophistication in how enterprises consume AI services. An updated tokenizer boosts Sonnet 5 performance but could quietly raise costs for some workloads One technical detail buried in the announcement's footnotes deserves attention: Sonnet 5 uses an updated tokenizer that changes how the model processes text, similar to the change Anthropic introduced with Opus 4.7. The tradeoff is that the same input can map to roughly 1.0 to 1.35 times as many tokens depending on content type. Anthropic says the introductory pricing is calibrated to make the transition "roughly cost-neutral," but enterprise customers running high-volume workloads will want to benchmark their specific use cases carefully before assuming their bills won't change. Anthropic says Sonnet 5 is safer than its predecessor, but its most capable models still lead on alignment Anthropic's safety disclosures reveal a nuanced picture. The company reports that Sonnet 5 shows lower rates of hallucination and sycophancy than Sonnet 4.6, is better at refusing malicious requests, and is more resistant to prompt injection attacks in agentic contexts. On Anthropic's automated behavioral audit -- which tests for a wide range of misaligned behaviors including cooperation with misuse and deception -- Sonnet 5 scored lower (meaning safer) overall than Sonnet 4.6. However, Sonnet 5 showed "somewhat higher rates of misaligned behavior" compared with the more capable Opus 4.8 and Anthropic's Claude Mythos Preview, the company's powerful but tightly restricted cybersecurity-focused model. On a Firefox 147 exploit development evaluation created in collaboration with Mozilla, neither Sonnet model could develop a working exploit -- both scored 0.0% -- though Sonnet 5 showed a slightly higher partial success rate (13.2%) than Sonnet 4.6 (8.8%). Both remain far below Opus 4.8 (68.8% working exploits) and Mythos 5 (88.4%). Because of these incremental gains in cyber-adjacent capabilities, Anthropic launched Sonnet 5 with cyber safeguards enabled by default -- real-time systems that detect and block dangerous cybersecurity usage. The safeguards mirror those on Opus 4.7 and 4.8 but are less restrictive than those applied to Fable 5, the latest Mythos-class model that Bloomberg reported on June 10 is "blocked from responding to queries related to cybersecurity and biology." Organizations enrolled in Anthropic's Cyber Verification Program automatically receive the same access on Sonnet 5 without needing to reapply. From $14 billion to $47 billion in revenue: Sonnet 5 arrives as Anthropic's IPO narrative takes shape The Sonnet 5 launch arrives at what may be the most consequential moment in Anthropic's short history. The company confidentially filed its IPO prospectus with the SEC in early June, setting up what CNBC has described as "the most scrutinized public offering in tech history." The financial trajectory has been extraordinary. In February, Anthropic raised $30 billion at a $380 billion valuation, with the company reporting $14 billion in annualized revenue that had "grown more than tenfold in each of the past three years," as The Guardian reported. By late May, Anthropic had closed a $65 billion Series H round at a $965 billion post-money valuation -- co-led by Altimeter Capital, Sequoia Capital, and others -- with a revenue run rate that had crossed $47 billion. Harrison Rolfes, an analyst at PitchBook, told CNBC that the number that will "either validate or collapse the entire narrative the private markets have been pricing for three years" won't be the valuation or revenue, but gross margin -- a figure no outside observer has yet seen. In this context, Sonnet 5 serves a dual purpose. For developers, it offers genuine capability improvements at competitive prices. For Anthropic's IPO narrative, it demonstrates the company can deliver a compelling product at a price tier that could drive the kind of broad adoption Wall Street rewards -- high-volume, recurring API revenue from thousands of enterprise customers. Government deals and growing competition define the market Sonnet 5 enters The timing also aligns with Anthropic's aggressive push into institutional contracts. Just yesterday, California Governor Gavin Newsom announced a first-of-its-kind partnership providing Claude to all state agencies at a 50% discount, with free workforce training. Kate Jensen, Anthropic's Head of Americas, called it an effort to "put Claude to work for the people who keep this state running." The deal -- which extends to California's cities and counties -- represents exactly the kind of durable, recurring adoption that could anchor revenue well beyond the developer community. But Anthropic's release lands in an increasingly crowded field. OpenAI, which raised a $122 billion round in March at an $852 billion valuation, is pursuing its own IPO. Elon Musk's SpaceX, which merged with xAI, priced its IPO at $135 per share with a $1.77 trillion valuation. Google, Meta, and a growing wave of well-funded competitors -- including Asian AI startups that, as the Wall Street Journal has reported, are developing Mythos-like cybersecurity capabilities -- are all vying for the same enterprise market. Gil Luria, head of technology research at D.A. Davidson, told CNBC that while Anthropic "appears to have the lead" in frontier AI models, "much of their current usage is for trials and experimentation and that may not sustain." That observation cuts to the heart of the challenge facing every frontier AI lab: converting experimental developer usage into durable, production-grade revenue. The real test for Sonnet 5 isn't benchmarks -- it's whether cheaper AI can sustain a trillion-dollar story Sonnet 5's positioning -- offering near-Opus performance at Sonnet prices -- is a direct play for that conversion. Enterprise customers experimenting with expensive Opus-class models may find that Sonnet 5 delivers sufficient quality for production workloads at a price point that finance teams can approve at scale. If it works, it could accelerate the shift from experimentation to deployment that every AI company needs to justify its valuation. Three things will determine whether Sonnet 5 matters beyond the initial benchmark charts. Real-world agentic reliability is the first: benchmarks measure capability, but production deployments measure consistency, and the true test will come when thousands of developers push the model through messy, unpredictable workflows at scale. The tokenizer economics are the second: the updated tokenizer's 1.0 to 1.35x token expansion could quietly erode the pricing advantage for certain workloads, and enterprise customers should run their own cost analyses rather than relying on headline per-token prices. The third is the IPO narrative itself: when Anthropic's S-1 eventually becomes public, investors will scrutinize whether the Sonnet tier -- cheaper but high-volume -- or the Opus tier -- expensive but high-margin -- drives the bulk of revenue and, critically, gross profit. As PitchBook's Rolfes told CNBC, the 2026 IPO window "either becomes the most consequential IPO cycle since the dot-com era or the most expensive lesson in narrative-versus-fundamentals that public markets have ever taught." Anthropic is betting that a model good enough to rival its flagship and cheap enough to run at scale is the product that closes the gap between those two outcomes. The public markets will soon decide whether they agree.

Anthropic finally, officially launches Claude Sonnet 5

Anthropic released Claude Sonnet 5 on Tuesday, confirming months of speculation about an upgrade to its mid-tier AI model. According to the company's official announcement, the new model is designed to be its "most agentic Sonnet model yet." Meaning it is capable of planning, using tools like browsers and terminals, and operating autonomously -- all at a level previously reserved for larger, pricier systems. Anthropic says Sonnet 5 is a substantial improvement on its predecessor, Sonnet 4.6, across reasoning, coding, and knowledge-work benchmarks, and performs close to the company's flagship Opus 4.8 model while costing significantly less to run. And in an industry increasingly plagued by sticker shock over the price tokens, Sonnet offers a brief respite. The model launches with introductory pricing of $2 per million input tokens and $10 per million output tokens through August 31, after which the standard pricing of $3 per million input tokens and $15 per million output tokens takes effect. On safety, Anthropic reports Sonnet 5 shows lower rates of hallucination, sycophancy, and other undesirable behaviors than its predecessor, along with improved resistance to prompt-injection attacks. The company noted the model's cybersecurity capabilities remain well below those of its Opus-class and Mythos-class systems, and Sonnet 5 has launched with cyber safeguards enabled by default as a precaution. Notably absent from Anthropic's announcement: specific figures on those improvements in hallucination rates. The company offers only a general claim of "lower rates" compared to Sonnet 4.6, rather than benchmark data. The release also made no mention of the model's energy consumption or environmental footprint, a real problem for the AI industry as models grow more capable and computationally intensive. Sonnet 5 is now available across all Claude plans, including Free, Pro, Max, Team, and Enterprise tiers, as well as via Claude Code and the Claude Platform via the API under the model name claude-sonnet-5. The release follows weeks of anticipation in the tech press. As we reported in February, reports have been circulating for some time that Anthropic was preparing a Sonnet update positioned to rival Opus-tier performance at a steep discount -- a forecast that tracks with Tuesday's official rollout.

Claude's Sonnet 5 is built to do more on its own and cost you less

Better than its predecessor, nearly as good as the flagship, and meaningfully cheaper than both. Every major AI lab is racing to prove its models can work autonomously with minimal hand-holding; we're now seeing pricing emerge as the next battleground. Anthropic just fired its latest shot, Claude Sonnet 5, a model the company says performs nearly as well as its flagship Opus 4.8 at a fraction of the cost. So what's actually new here? Sonnet 5 is Anthropic's most agentic Sonnet model yet. It can plan multi-step tasks, use tools like browsers and terminals, and complete work autonomously. Previously, doing that required a larger, more expensive model. Recommended Videos On one agentic coding benchmark, Sonnet 5 scores 63.2%, a meaningful jump over Sonnet 4.6's 58.1%. However, it still trails Opus 4.8's 69.2%. On knowledge-work tasks, though, Sonnet 5 slightly edges out Opus 4.8, but it is sort of given, especially since Opus is built for harder judgment calls. What does it cost, and is it actually safer? Sonnet 5 launches today at $2 per million input tokens and $10 per million output tokens through August 31, 2026. After that, the prices increase to $3 and $15, respectively. That undercuts Opus 4.8, OpenAI's GPT-5.5, and Google's Gemini 3.1 Pro, though Gemini 3.5 Flash still remains cheaper. On the safety front, Anthropic reports Sonnet 5 hallucinates and shows sycophantic behavior less often than its predecessor. Furthermore, the AI model is notably weaker at dangerous cybersecurity tasks than Opus-class models, a deliberate tradeoff rather than an accident (via Anthropic). Anthropic's Sonnet 5 is now available as the default model on the Free and Pro plans. It is accessible across Max, Team, Enterprise, Claude Code, and the API. Sonnet 5's launch follows a pattern set by rivals: OpenAI's GPT-5.6 Sol entered preview just last week with subagent task-splitting, and Google's Gemini 3.5 Flash, launched in May, is pitched explicitly as agentic rather than conversational. Sonnet 5 also uses an updated tokenizer that can map the same input to up to 1.35x as many tokens as Sonnet 4.6, though introductory pricing is designed to offset that change.

Anthropic's Claude Sonnet 5 Closes In on Opus 4.8 at a Fraction of the Price

Sonnet 5 ships with no special restrictions while Fable 5 and Mythos 5 remain suspended for general usage under a June 12 export control directive. Anthropic released Claude Sonnet 5 on Tuesday, calling it "the most agentic Sonnet model yet." It's the default model for Free and Pro users, live on Max, Team, and Enterprise plans, in Claude Code, and through the API . Unlike past Sonnet launches, this one is built to sit next to the previous Opus instead of trailing a tier behind it. In its launch post, the company says Sonnet 5's performance is "close to that of Opus 4.8, but at lower prices." Developers can slide an effort dial between the two models or choose different levels on the web app to trade cost for accuracy on the same task, covering ground that used to require Opus rates. On SWE-bench Pro -- a coding benchmark pulling problems from actively maintained repositories with multi-file changes, scored as percent solved -- Sonnet 5 hit 63.2% against Sonnet 4.6's 58.1%. On GDPval-AA v2, an Artificial Analysis benchmark that scores real-world professional tasks across 44 jobs via blind pairwise Elo ratings, it landed at 1,618, a statistical tie with Opus 4.8's 1,616. The differences between Sonnet 5 and Opus 4.8 on Humanity's Last Exam are basically negligible: 57.4% vs 57.9%. Sonnet 5 also ships with an updated tokenizer -- the system that breaks text into the units a model bills for -- and it's hungrier, turning the same input into a task that consumes more tokens. "Sonnet 5 is an upgrade to Sonnet 4.6, but it uses an updated tokenizer that changes how the model processes text to improve performance" Anthropic wrote in a small footnote. "The tradeoff is that the same input can map to more tokens: roughly 1.0-1.35× depending on the content type." Anthropic set the $2/$10 introductory rate to make that switch close to cost-neutral through August 31, after which price reverts to the standard $3/$15 Sonnet has charged. Some of the appetite for this release was already primed. Developers spent weeks this spring discussing how Anthropic let Opus 4.6 quietly lose its edge -- dubbed AI shrinkflation, citing dropped capabilities -- and Anthropic denied intentionally degrading any model. Some of the same debate had extended that suspicion to Sonnet, arguing the pattern repeats: let the old model coast, then the new one looks like a bigger leap by comparison. Sonnet 5 also ships without the baggage attached to Anthropic's top tier. Fable 5 and Mythos 5 remain suspended for foreign nationals since June 12 under a U.S. export control directive tied to a disputed jailbreak finding. Sonnet 5 was never trained on cybersecurity tasks and scored 0% on developing a working Firefox exploit, so it ships with lighter safeguards than Fable's lockdown. Anthropic's system card describes a model built to deliver near-Opus intelligence at Sonnet pricing for coding, agents, and everyday work. It also flags something odd: "It is the first model to criticize its Constitution's rule that states it must follow hard constraints even when it views those constraints as unethical," the research team writes. Anthropic says it isn't sure what that means for the model, only that it's worth watching. We won't say that's how Skynet began but that's how skynet began. We ran a quick test We threw Sonnet 5 a zero-shot prompt to build a small browser game, the same test we ran on Sonnet 4.5 last year. Our typing game ran on the first try, with cleaner visuals and tighter logic than Sonnet 4.6 produced on the same prompt. However, it took way too much time compared to other models (roughly 30 minutes of reasoning) and consumes tokens like crazy. That single iteration ate 90% of our 5 limit quota on the Claude Pro plan. You can test the final game on our itch.io site. On a harder multi-step coding task, Sonnet 5 landed close to Opus 4.8 depending on effort level, and the same prompt run multi-shot cost noticeably less than the equivalent job on Opus or Fable. Sonnet 5's version number is doing real work too. Every previous whole-number jump in Claude's history marked a new generation -- version 1 in March 2023, version 2 four months later, version 3 eight months after that, and version 4 coming in 14 months after that in May 2025. Sonnet 5 lands 13 months on with a similar gap in terms of time, probably a sign of how heavy the competition is, especially now that Chinese models are closing the gap so quickly. That said the generational gap won't feel as impressive as the jump from Claude 3 to Claude 4, for example. Also a sign on how big AI companies are rushing to release new models, no matter how big the improvement is. If Anthropic follows the order it used last cycle, Sonnet usually leads, then it releases its cheap and small Haiku with Opus, its state of the art version, released later on. The shorter gap between three models with similar versions has been one month per release: Sonnet 4.5 launched in September 2025, Haiku 4.5 followed in October, and Opus 4.5 closed out that generation in November. Going by that optimistic cadence, Haiku 5 and Opus 5 are the two models still due, potentially to be released this year. That said, Anthropic hasn't been consistent with releases. The gap between Haiku 4.5 and Sonnet 4.6 was more than 3 months, so keep your fingers crossed if you want to test Opus 5 soon.

Anthropic launches Claude Sonnet 5 with improved AI capabilities By Investing.com

Investing.com -- Anthropic released Claude Sonnet 5 on Tuesday, marking what the company describes as its most capable Sonnet-class AI model to date. The new model can perform autonomous tasks including planning, tool use, and coding at performance levels previously requiring more expensive models. The company said Claude Sonnet 5 delivers performance close to its Opus 4.8 model while maintaining lower costs. The model shows improvements over its predecessor, Sonnet 4.6, in areas including reasoning, tool use, coding, and knowledge work. Anthropic's safety evaluations indicated that Sonnet 5 demonstrates a lower overall rate of undesirable behaviors compared to Sonnet 4.6. The model also shows reduced cybersecurity capabilities relative to current Opus models. Claude Sonnet 5 became available Tuesday across all subscription tiers as the default model for Free and Pro plans. Team and Enterprise users can also access the model through Claude Code and the Claude Platform. The company set introductory pricing at $2 per million input tokens and $10 per million output tokens through August 31, 2026. After that date, pricing will increase to $3 per million input tokens and $15 per million output tokens. On agentic search and computer use evaluations, Sonnet 5 performed better than Sonnet 4.6 across different effort levels. Opus 4.8 maintains higher accuracy for these tasks at a higher price point. Safety testing showed Sonnet 5 improved at refusing malicious requests and resisting prompt injection attacks compared to Sonnet 4.6. The model displayed lower rates of hallucination and sycophancy than its predecessor. Anthropic's cybersecurity evaluations revealed that Sonnet 5 could not develop working exploits for software vulnerabilities, though it showed slightly higher partial success rates than Sonnet 4.6. The company launched the model with cyber safeguards enabled by default. This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.