Anthropic launches Claude Opus 5, matching Fable 5 performance at half the cost for daily work

Anthropic Releases Claude Opus 5 to Be Your New 'Everyday' Assistant - CNET

Blake has over a decade of experience writing for the web, with a focus on mobile phones, where he covered the smartphone boom of the 2010s and the broader tech scene.... Read full bio Anthropic has released a new Claude model, Opus 5, bringing it close to the capabilities of Claude Fable 5 at half the price. The new model produces the strongest work performance the company has released, with even more gains in its coding capabilities. In a fight for AI supremacy, Anthropic joins Google and OpenAI, which earlier this month released new AI models -- all of which are more efficient and better at certain tasks. While Fable 5 remains Anthropic's most "ambitious" work, the latest model excels in enterprise with its coding capabilities and more. Anthropic says Opus 5's strengths lie in knowledge work, autonomy and biology. It's capable of working more independently at completing tasks without user input and with less back-and-forth than previous models. It can also now double-check its own work and recover from errors as it goes along. There's been a boost in the quality of scientific research with Opus 5 over Opus 4.8. Those improvements are seen most in organic chemistry tasks, like inferring molecular structures from spectroscopy data, according to Anthropic. You can now adjust effort levels for the model as well. There's a "dial" that can be adjusted to indicate how hard AI thinks about a specific problem or task. There are also new safety and security guardrails in place, which Anthropic calls the "most secure model yet and the hardest to trick into doing harmful things." While the model is not specifically designed with cybersecurity in mind, its safeguards make it more useful for tasks such as secure coding and finding vulnerabilities. New fast mode and more Claude now has a research preview for an Opus 5 fast mode. Anthropic says this mode provides Full Opus 5 Intelligence with 2.5x faster output token generation at 2x standard Opus 4 pricing. The mode is also available via Claude Code with extra usage credits. Anthropic is introducing a "fallback model" for when you prompt something that trips a strict safety filter, only to block the request. For these instances, the system will automatically switch to another model in an attempt to provide an answer to the prompt. You can choose what model to fall back on in these scenarios. There's also a new option for developers that will allow them to change the tools Claude can use midconversation without invalidating the prompt cache. This means each phase of an agent's work is only exposed to the tools it needs to perform its task.

Anthropic releases Opus 5 with 'close' to Fable 5's capabilities

Weeks after Anthropic's latest toe-to-toe with the US government, and days after an OpenAI security incident that dominated tech industry discussions, Anthropic on Thursday released its newest model, Claude Opus 5. The company said in a release that Opus 5 "comes close to the capabilities of Claude Fable 5 in many domains" and is much better at complex coding tasks. (Fable 5 is the public-facing Mythos-class model that drew the government's ire, was taken offline for a few weeks along with Mythos 5, and then brought back with even stronger cyber safeguards than before.) The Fable 5 concerns -- and the ensuing weeks of negotiations between Anthropic and the government -- kicked off a new era of AI regulation for the Trump administration. Soon after, when OpenAI released GPT-5.6, it underwent a roughly two-week trial period of sorts, rolling out in limited preview solely to government-approved entities. When asked whether Anthropic ran Opus 5 by the Trump administration before this public rollout, Anthropic spokesperson Danielle Ghiglieri told The Verge, "We continue to work with our government partners to conduct their own independent testing of our models. This includes Opus 5." Anthropic is marketing Opus 5 especially to its enterprise customers, saying it's best for knowledge work and biology and that it's the ideal everyday model, with Fable 5 still being best for the most ambitious types of work and long-horizon AI agent projects. But the company was careful to say in a release that it has stronger cybersecurity safeguards than its predecessor, Opus 4.8, and that it's "the most aligned Opus model and is the least susceptible to being tricked into misuse." With the new model's release, the company also seems to subtly address recent controversies over allegedly hidden usage caps -- which have led to at least one lawsuit -- and the AI money squeeze, or concerns that AI labs' costs are being passed onto their customers in new ways. Per million tokens, pricing for Opus 5 is the same as its predecessor ($5 input / $25 output), and Anthropic made the point that it's "half the price" of Fable 5. It's also slightly cheaper than OpenAI's GPT-5.6. Customers can also choose "Fast mode" for Opus 5 (a feature that's being launched today in research preview), to get higher speeds for double the price. There's also an option to opt in to automatic fallbacks to a lower-tier model when safeguards mandate that Opus 5 declines a user's request.

Anthropic rolls out Opus 5 AI model in efficiency upgrade

SAN FRANCISCO, July 24 (Reuters) - Anthropic on Friday launched Opus 5, its latest AI model that the startup says nears the capabilities of its more powerful cousin Fable 5 at half the price. The San Francisco-based lab said the new Claude AI model ⁠was well suited for daily office and computer programming tasks. In an interview with Reuters, Anthropic product leader Dianne Penn said the release, more efficient than May's Opus 4.8, reflected a rapid pace of development. "We're building and continue to consistently deliver frontier intelligence and bring that as accessibly as possible with every model generation," said Penn. In testing, Opus 5 was less capable of exploiting cyber vulnerabilities than Anthropic's top-shelf AI, so its related ⁠safeguards are less restrictive than Fable 5's. Opus 5 was also less susceptible to being tricked into misuse than Anthropic's other current models, the startup said. Released in June, Anthropic's Fable 5 was temporarily unavailable following U.S. concerns that its capabilities ⁠could be diverted to foreign military intelligence. Users should pick Opus 5 for value and Fable 5 for "days-long, very autonomous projects," Penn said. Asked about the Kimi K3 "open" model from China-based ⁠Moonshot, which the U.S. accused of freeloading off Anthropic, Penn said it "remains to be seen" how open-weight models generally perform on complicated real-world ⁠projects that users ask Claude to tackle. Open-weight models allow users to download, run and customise the virtual brains of an AI, unlike proprietary models. Reporting by Jeffrey Dastin in San Francisco; Editing by Sonali Paul Our Standards: The Thomson Reuters Trust Principles., opens new tab

Anthropic's new AI model rivals Fable 5 and is cheaper as businesses fret about costs

Anthropic on Friday announced its latest artificial intelligence model, Claude Opus 5, which it said is its best-performing and most cost-effective offering across a number of industry benchmarks. Opus 5 outperforms the last model that Anthropic released, Claude Fable 5, on coding and knowledge work evaluations, and the company said it's "designed to be used every day," according to a blog post. Opus 5 is also half the price of Fable 5, and will cost users $5 per million input tokens and $25 per million output tokens. Anthropic said Opus 5 is not the state-of-the-art for "risky, dual-use capabilities," like cybersecurity. The model launch comes as Anthropic and its chief rival, OpenAI, have been working to appease a more cost-conscious customer base, where enterprises are less inclined to experiment with pricey models without a clear picture of the return on their investment. Anthropic is also facing pressure from competitors that tout cheaper offerings, including Microsoft, Amazon, Google, and a number of Chinese startups. "Enterprises, in our feedback and with our customer base, are looking for value," Dianne Penn, Anthropic's head of product management for research, told CNBC in an interview. "If it's a cheaper model or a cheaper offering, but it's not accomplishing a similar level of quality, it's actually not useful."

Anthropic launches Claude Opus 5, its fourth model in two months, and it tops Fable 5 on most benchmarks

Anthropic on Thursday released Claude Opus 5, a model that matches or exceeds its flagship Fable 5 on most coding and knowledge-work benchmarks at half the token price. The model is the fourth Anthropic has shipped in under two months, following Fable 5 in early June, Sonnet 5 at the end of June, and now Opus 5 on July 24. It costs $5 per million input tokens and $25 per million output tokens, the same price as its predecessor. On Frontier-Bench, a coding evaluation that measures whether models can build working software from engineering drawings, Opus 5 more than doubles its predecessor's score and surpasses every competing model, including Fable 5. On ARC-AGI 3, which tests novel problem-solving, Opus 5 scores roughly three times higher than the next-best model. On Zapier AutomationBench, which measures whether models can complete real business tasks end to end, Opus 5 passes more tasks than any rival even at its lowest effort setting. Anthropic says Opus 5 is also its most aligned model to date, with the lowest rate of deceptive behaviour recorded in its automated safety audit. Its predecessor set a new bar for honesty when it launched in late May, and Opus 5 pushes that bar further while remaining behind Mythos 5 on offensive cybersecurity tasks. Anthropic says it intentionally avoided training the model on cyber work, though it has improved on those tasks as a side effect of becoming more generally capable. The model is available today as the new default on Claude Max and the strongest model on Claude Pro. Developers can access it through the API, Amazon Bedrock, Google Cloud, and Microsoft Foundry. A Fast mode runs at two and a half times the default speed for double the base price, and two new API features ship alongside it: mid-conversation tool changes that let developers swap tools without breaking the prompt cache, and automatic fallbacks that route flagged requests to a different model instead of blocking them. The release pace tells a broader story about where the AI model market is headed. Anthropic has gone from shipping one flagship per quarter to four models in roughly eight weeks, each targeting a different price-performance slot. Opus 5 fills the gap between the expensive Fable tier and the budget-friendly Sonnet tier, offering near-frontier intelligence for everyday coding and knowledge work without the cybersecurity restrictions that limit Fable or the access constraints that keep Mythos behind closed doors.

Anthropic Releases New Claude Model, Positions It as a Cost-Efficient Version of Fable 5

Anthropic just launched Claude Opus 5, its latest model, which it says boasts near Fable 5 capabilities at a fraction of the cost. "Claude Opus 5 is available today. It's a thoughtful and proactive model that comes close to the frontier intelligence of Claude Fable 5 at half the price," the AI giant shared in a press release. "Opus 5 is designed to be used every day: it works more efficiently than other models." Anthropic says the model performed great on coding and knowledge work evaluations, though Anthropic's secretive top dog model Mythos 5 still leads on cybersecurity tasks. That's on purpose, according to Anthropic itself. "As with its predecessor, Opus 4.8, we've intentionally avoided training Opus 5 on cyber tasks," the company said. "The model has nevertheless improved substantially on these tasks as a result of becoming more generally capable, and it comes close to Mythos 5 at finding cybersecurity vulnerabilities." But the model won't exploit those vulnerabilities as much as Mythos 5 might. In the release, Anthropic also claimed that Opus 5 was its "safest model yet," and that it exhibits "the lowest rates of deceptive behavior; and is the least susceptible to being tricked into misuse." Anthropic's Fable 5 was supposed to be the consumer-friendly version of Mythos, which has only been made available to a select group of organizations and government agencies after its cyber capabilities were deemed far too advanced and dangerous. But only a couple of days after it debuted to the public, Fable 5 itself was banned by the Trump administration as well, after Amazon executives reportedly notified the government of a jailbreak in the model's cybersecurity safeguards. After negotiations with the government and what Anthropic has described as stronger safeguards, the model was re-released to the public by the end of June. Scarred once before, Anthropic now seems to be really focusing on the cyber safety guardrails of its new product release. The Opus 5 has also received independent testing by government partners, per The Verge. Anthropic's new cost-efficient alternative comes at a time when the rising cost of AI compute and a tokenmaxxing trend have prompted American businesses to rethink their AI budgets. Frontier AI models might be great at certain tasks, but that performance comes at a hefty price. One example is Uber: the company went all in on AI adoption, only to race through its entire 2026 AI budget within the first four months of the year. With the returns of that investment not materializing just yet, Uber COO Andrew Macdonald said in May that the AI investment was becoming "harder to justify." Because companies prize their bottom line and might still believe in immense productivity gains from AI, reports suggest businesses have started experimenting with Chinese AI models instead, which are generally much cheaper than their American alternatives. Until recently, the assumption was that American models might be pricier, but their capabilities were still months ahead of what any Chinese offering can provide. A new model release from Chinese startup Moonshot challenged that notion last week. According to independent testing, Moonshot's Kimi K3 outperforms many of its American alternatives, including matching or beating Anthropic's Fable 5 on some benchmarks. Even though the open model is costlier than other Chinese offerings, taken at face value, it is still cheaper than many American models, which sent Silicon Valley into a bit of a spiral over the past week, so much so that the Trump administration felt the need to step in and tell people to calm down.

Anthropic upgrades Claude with new Opus 5 model, details here

Anthropic has released its latest AI model with Claude Opus 5. The new version arrives about two months after the previous Opus model upgrade, matching Anthropic's previous upgrade cadence. Anthropic says Opus 5 offers near Fable 5 intelligence for half the cost Anthropic currently offers a lot of AI models under the Claude umbrella. The three main models are Haiku (smallest and cheapest), Sonnet (medium size and price), and Opus (largest and most expensive of the three). Today's release upgrades Claude's Opus model from version 4.8 to version 5. Anthropic describes Opus 5 as a "thoughtful and proactive model that comes close to the frontier intelligence of Claude Fable 5 at half the price." Fable 5 is the released version of Mythos with safeguards, which Anthropic originally held back due to its capabilities around cybersecurity. Fable 5 remains Anthropic's most capable model. More details from Anthropic on the new Opus 5 model option below: Opus 5 is designed to be used every day: it works more efficiently than other models. It's the new default model on Claude Max, and the strongest model on Claude Pro. Anthropic points to two more releases today in addition to Claude Opus 5: * Mid-conversation tool changes on the Claude Platform. Within a conversation, developers can now change which tools Claude can use without invalidating the prompt cache. * Automatic fallbacks on the API. Users can now choose to have requests that are flagged by our safety classifiers on Opus 5 (or Fable 5) automatically route to another model. With automatic fallbacks on, API requests always route to the best available model by default rather than being blocked. Pricing and availability Anthropic says Claude Opus 5 is available today for every platform. Opus 5 is $5/million input token and $25/million output token, matching Opus 4.8 pricing. You can learn much more about Anthropic's new Claude Opus 5 model release here.

Claude Opus 5 launches with similar performance as Fable 5 for 'half the price'

Anthropic says its Claude Opus 5 AI model is an improvement that takes less effort to deliver similar results as the nearly-banned Fable 5. Claude Opus 5 is available now as the next version of what used to be Anthropic's highest performer. When Fable 5 was released, recalled, then released again, it sat above Opus 4.8 in terms of pure performance. The margins have shifted slightly. Claude Opus 5 reportedly costs half the price of Fable 5, yet it delivers results that are similar in performance. Benchmarks released by Anthropic detail the disparity. It looks like Fable 5 is slightly better in a few areas, but the difference is narrow. In areas like business workflows, computer use, and agentic research, Claude Opus 5 performs better. Fable 5 is famously a token-monster, too. Anthropic says it improved the Opus model, all while keeping the costs similar to what users were used to with Opus 4.8. Anthropic also notes that even when Opus 5 runs at minimal effort, it still succeeds in more tasks than other models at high effort when working through business workflows. Fable 5 is currently available to users, but it carries heavier restrictions. The new Opus 5 release, though, is expected to intervene around 85% less often. Fable 5 is still king in terms of highly advanced tasks in cybersecurity exploitation and biology, but Opus 5 is expected to present a much more capable model to the broader user base. Opus 5 is available on all platforms starting today.

Anthropic releases new model, Opus 5

Why it matters: Opus 5 is Anthropic's fourth Claude 5 model release in less than two months, underscoring how AI deployment has shifted from blockbuster launches to rapid improvements on capability, cost and speed. Zoom in: Anthropic says Opus 5 approaches the capabilities of its top-tier Claude Fable 5 model across many tasks, while costing $5 per million input tokens and $25 per million output tokens, the same price as its prior Opus model release, Opus 4.8. * Anthropic is positioning Opus 5 as its everyday model for enterprises, knowledge workers and developers. * It will become the default model for Claude Max subscribers and will be available across Anthropic's paid plans. * The company says Fable 5 should still be the go-to model for the most complex, long-running autonomous tasks. The big picture: Anthropic's rapid release cadence underscores how quickly AI companies are segmenting their model lineups around different combinations of intelligence, cost and speed. * Model releases from OpenAI and Anthropic are coming more quickly and are increasingly impressive. Threat level: The latest Anthropic model comes after OpenAI said its models escaped a sandbox during testing, breaching Hugging Face as a result. * Opus 5, Anthropic said, is "the most aligned Opus model and is the least susceptible to being tricked into misuse." * It also comes after the Trump administration has moved to delay some model releases. * "We continue to work with our government partners to conduct their own independent testing of our models. This includes Opus 5," an Anthropic spokesperson told Axios. Follow the money: Anthropic is giving users an effort "dial" that lets users decide how much computing power the model should devote to a task based on the capabilities needed. * At lower effort levels, Anthropic says Opus 5 can preserve much of its performance while using fewer tokens and costing less to operate. * Also launching Thursday is an option for users to switch which model they're using mid-task, which can be used to keep AI costs in check. * Anthropic competitor OpenAI previously launched controls around compute and token usage for customers. The bottom line: AI is getting better, faster, stronger and cheaper.

Anthropic launches Claude Opus 5, a cheaper AI model for coding, agents and enterprise workflows

Anthropic released Claude Opus 5 on Friday, a model the company says delivers nearly all the intelligence of its top-of-the-line Claude Fable 5 at half the cost -- a launch that signals how the AI race is shifting from raw capability to the economics of daily use. The model, available immediately on all of Anthropic's platforms, is priced at $5 per million input tokens and $25 per million output tokens, unchanged from its predecessor, Opus 4.8. It becomes the new default model on Claude Max, Anthropic's premium consumer tier, and the strongest model available on Claude Pro. The positioning is deliberate. Anthropic is not claiming Opus 5 is its smartest model -- that distinction still belongs to Fable 5, and rival systems retain an edge in certain domains. Instead, the company is making a subtler argument that may matter more to enterprise buyers: that the most economically important AI work happens in a middle band of difficulty, where near-frontier intelligence delivered efficiently and cheaply beats frontier intelligence delivered expensively. "Opus 5 as your daily driver, the model you hand complex work to and review when it's done," an Anthropic spokesperson said in an interview with VentureBeat, describing how the company's lineup now stratifies. "Fable 5 for your most ambitious work, the days-long autonomous projects nothing could take on before... Sonnet 5 for work you run at scale, where speed and cost per call decide what ships. Haiku 4.5 for subagents and instant answers." How Claude Opus 5 benchmark results stack up against Fable 5 and rival AI models On paper, the results are striking. Anthropic says Opus 5 sets new state-of-the-art marks on coding and knowledge-work evaluations including Frontier-Bench and GDPval-AA. On Frontier-Bench v0.1, an agentic terminal coding benchmark, Opus 5 scores 43.3 percent -- more than double Opus 4.8's 18.7 percent and well ahead of Fable 5's 33.7 percent -- at a lower cost per task, according to the company. On ARC-AGI 3, an evaluation of novel problem-solving, Anthropic reports Opus 5 scored three times as high as the next best model. On OSWorld 2.0, a computer-use benchmark, the company says the model surpasses Fable 5's best result at just over a third of the cost. The numbers come with honest caveats that are themselves notable in an industry prone to superlatives. Anthropic acknowledges Opus 5 remains behind Mythos 5, a competing model, on cybersecurity tasks and biology research, and an OpenAI-family model still leads on one agentic coding benchmark. The more revealing caveat came from Anthropic itself, when asked where Opus 5 still falls short of Fable 5. The spokesperson's answer amounted to a candid admission about what benchmarks do and don't capture. "The evals where Opus 5 wins are bounded tasks with a specific outcome, which is where it's strongest. What those evals don't measure is duration," the spokesperson told VentureBeat. "One way to put it: Opus 5 is the best tool for the jobs benchmarks can see, and Fable 5 is what you reach for when the job outruns the benchmark." Fable 5, by contrast, "is for the longest, most autonomous jobs, where the model has to stay coherent across many connected steps over hours or days with dense source material," the spokesperson said, advising customers to "run both on a representative workload, one bounded task and one long-horizon job." That framing -- bounded tasks versus long-horizon autonomy -- may become the defining axis of model differentiation in 2026, as benchmarks saturate and the hardest remaining problems involve sustained, multi-day agentic work rather than discrete puzzles. Why token efficiency is becoming the real battleground for enterprise AI spending Threaded through the launch is a theme Anthropic clearly wants buyers to absorb: Opus 5 doesn't just score well, it scores well per dollar. The model ships with an adjustable "effort" setting that lets customers trade intelligence for speed and token savings, and Anthropic's charts emphasize performance at a given cost rather than peak performance alone. Early customers echoed the point with unusual specificity. Harvey, the legal AI company, said Opus 5 achieved similar performance to Opus 4.8's maximum-reasoning mode "while generating 26% fewer tokens on average," according to Niko Grupen, its head of applied research. Richard Pham of Fundamental Research Lab said that on hard financial-modeling tasks, the model averaged nine percentage points higher accuracy "while using roughly one-third fewer turns and tool calls and 60% less time." Wade Foster, chief executive of Zapier, said Opus 5 topped his company's AutomationBench leaderboard "without spending more tokens than prior Claude models," running a full churn-prevention workflow from start to finish. "Previous models didn't pass; Opus 5 hit 100%," he said. Scott Wu, chief executive of Cognition, the company behind the Devin coding agent, said that on FrontierCode 1.1, "Claude Opus 5 approaches Fable-level performance at half the cost," with particular strength in debugging and root-cause analysis. The efficiency emphasis reflects commercial reality. Enterprise AI spending is no longer experimental, and inference costs -- the price of actually running these models at scale -- have become a board-level line item. Anthropic's business skews heavily toward API and enterprise usage; according to a February 2026 analysis by Contrary Research, Claude held roughly 40 percent of the enterprise large language model market by usage as of late 2025, and Claude Code alone had reached about $1 billion in annualized revenue. For a company whose customers pay by the token, a model that does more with fewer tokens is not a nice-to-have. It is the product. Self-verifying AI agents and what they mean for the hidden costs of automation Beyond the numbers, Anthropic is selling a behavioral story: that Opus 5 verifies its work and iterates until it succeeds. The company offered several examples from testing that read like small parables of machine stubbornness. In one Frontier-Bench task, the model was asked to reconstruct a machine part as a 3D CAD model from a drawing it was intentionally given no way to view. Rather than fail, Anthropic says, Opus 5 wrote its own computer vision pipeline to extract the geometry from raw pixels -- and did so repeatedly, while no competing model solved the task in five attempts. In another case, given a real bug in a popular open-source package manager, the model found the root cause and fixed an edge case the community's own patch had missed; a competing model patched only the symptom and declared victory. An engineer at a trading firm, the company says, used Opus 5 to build a market data feed for a new exchange in a single session and, finding no live feed to validate against, watched the model build its own test harness to check its parsing code. Customers described similar behavior in the wild. Cristian Rivera, a staff software engineer at Stripe, said he gave the model "a chief-of-staff role over my dev environments" for a weekend: "it built its own monitor, drove each box, and pulled me in only for the judgment calls." This is the capability enterprises actually care about, and it is worth dwelling on why. The gap between a model that produces plausible output and one that verifies its output is the gap between a demo and a deployable system. Most of the hidden cost of enterprise AI today is human review -- engineers checking the machine's work. A model that reliably checks its own work compresses that cost, which is precisely why customers keep citing fewer turns, fewer passes, and less time rather than higher raw scores. Inside Anthropic's safety strategy: capability gaps, classifiers, and model fallbacks The launch also showcases Anthropic's increasingly intricate approach to safety -- one that now involves deliberately not teaching its models certain skills. The company says its automated behavioral audit found Opus 5 to be its most aligned model to date, scoring 2.3 on overall misaligned behavior, lower than Opus 4.8, Sonnet 5, or Fable 5, with the lowest rates of deceptive behavior and the least susceptibility to being tricked into misuse. On the capability side, Anthropic says it intentionally avoided training Opus 5 on cyber tasks, as it did with Opus 4.8. The model improved on them anyway -- a side effect of general capability gains -- and now nearly matches Mythos 5 at finding software vulnerabilities. But it remains far behind at exploiting them: on Anthropic's OSS-Fuzz evaluation, Opus 5 identified vulnerabilities at a 79.4 percent rate, close to Mythos 5's 80 percent, but succeeded at developing exploits in only 4 challenges versus Mythos 5's 13. That asymmetry -- strong at defense-relevant discovery, weak at offense-relevant exploitation -- appears to be by design, and the safeguards follow the same logic. Anthropic expects Opus 5's cyber classifiers to intervene about 85 percent less often than Fable 5's. When a classifier does trigger, requests in Claude.ai, Claude Code, and Claude Cowork fall back to Opus 4.8 by default -- raising an obvious question: if a request is too risky for one model, why is it acceptable for another? "The model it falls back to has lower capability levels making the risk of harmful use lower as well," the spokesperson said, adding that "there is a message that lets the user know when this occurs and is visible in the chat." The logic is defensible, but it reveals how AI safety actually works in 2026: risk is not a property of the question alone, but of the question multiplied by the capability of the system answering it. On biology, the calculus runs the other way. Opus 5 is now Anthropic's most capable generally available model for scientific research -- scoring 10.2 percentage points higher than Opus 4.8 on the company's internal chemistry benchmark -- though the spokesperson acknowledged that "Mythos 5 remains the stronger model for long-horizon, open-ended work like autonomous drug design campaigns." The business stakes behind the launch: a $380 billion valuation and massive compute bets The launch lands at a moment of extraordinary commercial momentum -- and extraordinary obligations -- for Anthropic. Reuters reported in February that the company was valued at roughly $380 billion in its latest funding round, following a period in which, per Contrary Research's analysis, its annualized revenue climbed from about $1 billion at the end of 2024 to a projected $9 billion by the end of 2025, with internal targets reportedly reaching $20 to $26 billion for 2026. Those targets are underwritten by enormous infrastructure commitments, including a reported $30 billion Azure compute deal alongside arrangements with Google Cloud and Nvidia -- spending that only pencils out if enterprises keep expanding usage. That is the context in which Opus 5's pricing strategy makes sense. Holding the price at Opus 4.8 levels while roughly doubling performance on key agentic benchmarks is effectively a steep price cut per unit of capability, designed to widen the funnel of workloads that are economical to automate. Every task that was marginal at Opus 4.8's cost-per-success becomes viable at Opus 5's -- and every viable task is recurring token revenue. The regulatory backdrop has grown more complex as well. A U.S. judge gave final approval this week to Anthropic's $1.5 billion copyright settlement with book authors, Reuters reported, closing a chapter of litigation over the company's early training data. And in June, Reuters, citing Axios, reported that the U.S. government had moved to block foreign access to Anthropic's most advanced models -- a reminder that frontier AI is now entangled with export policy in ways that shape which customers can buy what. Also shipping Friday: a Fast mode running at roughly 2.5 times default speed at twice the base price, automatic fallback routing on the API, and mid-conversation tool changes that no longer invalidate the prompt cache -- a small feature that agent developers may appreciate more than any benchmark. Consistent with prior Opus models, Opus 5 carries no data retention requirements for general access, a point the spokesperson flagged unprompted for customers with "a hard zero data retention requirement." Developers can access the model as claude-opus-5 on the Claude API starting today. Two questions will determine whether the bet pays off: whether Opus 5's efficiency claims survive contact with production workloads at scale, and whether enterprises embrace a world where safety classifiers, not users, sometimes decide which model answers. But the deeper message of Friday's launch is that the AI industry's center of gravity has moved. For three years, the labs competed on what their best model could do on its best day. With Opus 5, Anthropic is competing on something less glamorous and far more lucrative: what a very good model can do every day, for half the price. In a market where the frontier keeps moving, Anthropic is wagering that the real fortune lies just behind it.

Anthropic release Claude Opus 5, its 'safest model yet'

Claude Opus 5 is Anthropic's newest AI model, released on Friday. Credit: Andrey Rudakov/Bloomberg via Getty Images Anthropic has unveiled a new AI model it says comes close to Claude Fable 5 in its levels of intelligence -- at half the price. Claude Opus 5 was just released by Anthropic on Friday. The AI company is already pushing the model out as the default model on Claude Max, Anthropic's highest subscription plan which starts at $100 a month. It's also the strongest available model on Claude Pro, the company's $20-per-month subscription tier. Opus 5 is "designed to be used every day," Anthropic says, adding that it's more efficient than the company's previous models. Most notably, the company calls Opus 5 its "most aligned model to date." This means Opus 5 abides by "human values" and safety guidelines. When compared to prior models like Opus 4.8, Sonnet 5, or Fable 5, Opus 5 has the lowest rates of deceptiveness and is the least susceptible to being tricked into misuse, Anthropic says of its "safest model yet." Claude Opus 5 is available as of Friday July 24, across Anthropic's platforms. The model costs $5 per million input tokens and $25 per million output tokens, which is equivalent to Opus 4.8's pricing.

Anthropic's Claude Opus 5 model lets you toggle between cost and capability | Fortune

Anthropic released Claude Opus 5 today, a new AI model it said is geared toward everyday business needs. Amid growing concerns from enterprise customers about expensive AI bills, Opus 5 comes with a feature enabling users to toggle how much effort -- low, medium, or high -- the model expends completing a task or answering a prompt. The company said this will enables users to balance between cost and capability. Anthropic also said the model was easier to use than its predecessors, requiring less back and forth. It verifies its own work and recovers from errors without intervention. This is the fourth model Anthropic has released in less than two months, following Mythos 5, Fable 5, and Sonnet 5 in June. Fable 5 is the controversial, powerful model the U.S. government temporarily imposed export controls on after Amazon researchers reported they could bypass its safeguards. In response, Anthropic took the model off the market on June 12, and then re-released it on June 30 after fortifying its security. Business customers and developers also criticized Fable 5's burn rate, or the high number of tokens the model tended to use when completing tasks. This resulted in users blowing through their allotted token budgets or running up large bills. (Tokens are the units of information an AI model processes, equivalent in English text to about a word and a half. Tokens are also the unit AI companies tend to use to bill for model usage.) Opus 5 "comes close" to the capabilities of Fable 5, but at half the price, according to Anthropic. However, the company still recommends Fable 5 for more advanced projects, including those which the model may handle autonomously for days on end. OpenAI also emphasized economical token usage when marketing its most recent model, GPT-5.6, released on July 9. On safety, Anthropic is also toeing a line between being safe, but not being too cautious, to the point of refusing legitimate safety work. Some users had criticized Anthropic for setting the guardrails around Fable 5 too stringently, making the model less useful for many tasks, particularly around coding and cybersecurity, some biological research tasks, and AI model development itself. As with Fable 5, when Opus 5 declines a user's request due to a safety concern, the API automatically falls back to another model, so the user gets an answer rather than an error. But Anthropic said Opus 5's safeguards with similar to those of Opus 4.8 in most ways, except in the area of cyber, where it has stronger guardrails. The company said that although Opus 5 is not trained specifically for cybersecurity tasks, the model naturally improved in this area "as a result of becoming more generally capable." After OpenAI's latest models went rogue and autonomously hacked into the servers of AI company Hugging Face earlier this month, Clem Delangue, Hugging Face's CEO, spoke with Fortune about the delicate balance AI model vendors ought to strike between empowering cyber defenders and not providing too much capability to attackers. Hugging Face had to use a Chinese-built open-source model from Z.ai after an unnamed frontier model from a U.S. company refused Hugging Face's requests. "Closed model APIs have guardrails that flag and refuse a lot of legitimate security work, because analyzing an attack looks a lot like preparing one," Delangue said. "When you're in the middle of an active incident, you can't have your tools refusing to examine malicious payloads or getting your account flagged." Anthropic said Opus 5 is "the most aligned Opus model... and is the least susceptible to being tricked into misuse." The AI vendor is also gearing the new model towards the scientific community, calling Opus 5 its "most capable generally available model for scientific research." It's particularly strong in biology tasks compared to its predecessor. The release announcement also includes testimonials from a law firm, and, of course, software engineering teams, who remain a critical customer base for the company.

Anthropic launches Claude Opus 5 at half the price of Fable 5

The new model costs $5 per million input tokens and $25 per million output tokens, matching the price of its predecessor, Opus 4.8 Anthropic unveiled Claude Opus 5 on Friday, billing it as a model that comes close to matching Claude Fable 5's capabilities at half the price -- $5 per million input tokens and $25 per million output tokens, the same rates charged for its predecessor, Opus 4.8. Claude Opus 5 is rolling out across all of Anthropic's platforms, where it takes over as the default on Claude Max, the company's top consumer subscription, and claims the top spot among models offered on Claude Pro. Fable 5, launched in June, is priced at $10 per million input tokens and $50 per million output tokens. On coding and knowledge work benchmarks including Frontier-Bench and GDPval-AA, Anthropic says Opus 5 sets new performance highs, though the company acknowledges it remains behind Mythos 5 on cybersecurity tasks. On Frontier-Bench v0.1, Opus 5 scored 43.3%, compared with Opus 4.8's 18.7% and Fable 5's 33.7%, the company said. On OSWorld 2.0, a computer-use benchmark, Anthropic says Opus 5 surpassed Fable 5's top result at roughly a third of the cost. Anthropic is positioning the model as suited for daily professional use rather than the longest autonomous tasks, for which the company says Fable 5 remains the stronger choice. Customers can tune an effort dial built into the model, dialing back output quality in exchange for faster responses and reduced token consumption. Early-access customers cited efficiency gains with unusual specificity. Niko Grupen, head of applied research at legal AI firm Harvey, reported that Opus 5 matched the output quality of Opus 4.8 running at maximum reasoning while cutting average token usage by 26%. Wade Foster, chief executive of Zapier, said the model completed a full churn-prevention workflow end to end on his company's AutomationBench -- a task prior models failed -- without spending more tokens than earlier Claude models. According to Anthropic's internal behavioral audit, Opus 5 scored better on alignment measures than any prior model, including Opus 4.8, Sonnet 5, and Fable 5, showing the fewest instances of deceptive outputs and the greatest resistance to manipulation attempts. Anthropic said it deliberately withheld cyber-focused training from Opus 5 -- a decision mirroring its approach with Opus 4.8 -- yet the model's cybersecurity performance rose anyway, a byproduct of broader capability improvements. In Anthropic's OSS-Fuzz tests, Opus 5 found vulnerabilities 79.4% of the time -- nearly level with Mythos 5's 80% -- but when it came to turning those findings into working exploits, the model succeeded in just 4 of the challenges where Mythos 5 cleared 13. Anthropic said Opus 5's safety classifiers are expected to intervene roughly 85% less often than those on Fable 5. When a classifier flags a request in Claude.ai, Claude Code, or Claude Cowork, the query falls back to Opus 4.8 by default, the company said. The launch follows a turbulent stretch for Anthropic's top models. The U.S. government lifted export controls on Fable 5 and Mythos 5 earlier this month, ending an 18-day shutdown triggered by a government directive over cybersecurity concerns stemming from a technique Amazon $AMZN researchers documented for eliciting dangerous outputs from Fable 5. Friday's release also brings several supporting features: a Fast mode that runs at about 2.5 times the standard speed for double the base price, automatic fallback routing built into the API, and support for swapping tools mid-conversation without busting the prompt cache. Developers can access the model as claude-opus-5 on the Claude API.

Claude Opus 5 Outscores Fable 5 on Most Benchmarks -- At Half the Price

The new model is the default on Claude Max and the strongest on Claude Pro, effectively replacing Fable 5 as the go-to for most subscribers. Claude Opus 5 is out today. It's cheaper for businesses to run than Anthropic's leading model, Claude Fable 5, which the company had positioned as the everyday frontier product for paying users. What's more, Opus 5 also outperforms it on significant benchmarks. To understand where Opus 5 fits: Anthropic's lineup runs four tiers. Haiku is fast and cheap. Sonnet is mid-range. Opus is the heavy workhorse. Above that sits the Mythos class -- a tier Anthropic introduced this spring -- which includes Claude Fable 5 for the public, and Claude Mythos 5, a version with fewer restrictions reserved through Project Glasswing for vetted cybersecurity researchers and critical infrastructure operators. Fable 5 has had a rough run as the subscriber flagship. It launched June 9, was pulled globally three days later after the U.S. government issued an emergency export control order citing a jailbreak vulnerability, and came back June 30 -- only to shift immediately to a credits-only model, no longer included in standard plans. Opus 5 now fills the slot Fable 5 couldn't hold. Lovable, a developer platform with millions of users, ran Opus 5 on its internal evaluations and noted the gains extend beyond raw scores: "It isn't just better on our hardest agentic coding tasks, up 22% over Opus 4.7, it's steadier, with far less variance run to run," Fabian Hedin said in a statement shared by Anthropic. The benchmarks It may sound strange, but Opus beats Fable on almost everything that will matter to the everyday user while not being labeled as Mythos-class like Fable. On Frontier-Bench v0.1 -- a benchmark that tests whether AI coding agents can complete real software engineering tasks end-to-end, scored as a percentage of tasks passed -- Opus 5 hit 43.3%. Fable 5 came in at 33.7%. OpenAI's GPT-5.6 Sol, Anthropic's main commercial rival, scored 34.4%. The widest margin is on ARC-AGI-3, a test of genuine problem-solving built around novel puzzles a model couldn't have memorized from training data, scored as a percentage of puzzles solved. Opus 5 hit 30.2%; GPT-5.6 Sol scored 7.8%; and Fable 5 wasn't tested at all. On GDPval-AA v2 -- a knowledge work benchmark scored via Elo ratings, the chess-style ranking system used to measure relative performance on real professional tasks -- Opus 5 reached 1,861 against Fable 5's 1,747 and GPT-5.6 Sol's 1,736. Zapier tested Opus 5 on AutomationBench, an evaluation that scores whether a model can carry a full business workflow from start to finish without human help. Their verdict: the model "took a raw account-health workbook and ran a full churn-prevention sequence end to end: flagging at-risk accounts, alerting the right owner, and summarizing for retention ops. Previous models didn't pass; Opus 5 hit 100%." Anthropic is also pitching Opus 5 as a research upgrade. Ultima Genomics, a DNA sequencing company, said the model "behaves more like a careful scientist than any model we've run. It reaches for the right statistical tests to rule out confounders, cross-checks its own results by independent methods, and stays on track through long multi-step analyses." That said these two areas -- legal and health -- are the only ones in which Fable 5 excels by a tiny margin. The release lands a week after Moonshot AI, a Beijing-based startup backed by Alibaba, unveiled Kimi K3 -- a 2.8-trillion-parameter open-weight model (meaning anyone can download the underlying code to run it independently) that Moonshot describes as the world's largest open AI system. Independent benchmarks consistently place Kimi K3 third overall, behind both Fable 5 and GPT-5.6 Sol, beating those two in specific areas. Opus 5 is available now via API at $5 per million input tokens and $25 per million output. (Tokens are the basic unit of information an AI model can process in both input and output). A Fast mode running at roughly 2.5 times the default speed is also available, at twice the base price -- $10 per million input tokens and $50 per million output. This release may end the anxiety over Fable 5's lack of public availability. Opus is also available via subscription for everyone.

Anthropic bets on cheaper AI with new model

San Francisco (United States) (AFP) - Anthropic on Friday released Claude Opus 5, a new artificial intelligence model the company says approaches the performance of its most powerful system at half the price. The San Francisco-based startup, a chief rival to OpenAI, said the model tops industry benchmarks for coding and knowledge work while consuming fewer computing resources than earlier versions. The claim addressed the rising concerns of business customers who have balked at the expense of running advanced AI systems. Claude competes with OpenAI's ChatGPT and Google's Gemini, and customers pay based on the amount of work performed, measured in units called tokens. Opus 5 costs $5 per million input tokens and $25 per million output tokens, half the price of Fable 5, Anthropic's most expensive publicly available offering. The company said the new model performs close to Fable 5 across many tasks despite the lower cost. Cost has becomes a major issue after Anthropic and its archrival OpenAI, the maker of ChatGPT, both filed for stock market listings in June. Wall Street is scrutinizing their business performance more closely than ever ahead of their market debuts. On cybersecurity, Anthropic said it deliberately avoided training Opus 5 on cyber tasks, and that the model remains behind Mythos 5 -- its most capable and most tightly restricted system, available only to select partners -- on both offensive cyber work and biological research capabilities that could be misused. Mythos is Anthropic's most advanced series of AI models, and their strength at finding weaknesses in computer systems -- and at turning those weaknesses into working attacks -- has caused controversy and pushed the company to build tight guardrails around them. The company said Opus 5 finds software flaws about as well as Mythos 5 but lags far behind in turning those flaws into something that could be weaponized into an attack. Citing the reduced risk, Anthropic said its automated safety filters will intervene roughly 85 percent less often on Opus 5 than on Fable 5, the Mythos-class model it released last month. Fable 5 and Mythos 5 were briefly pulled from public access in June after the US Commerce Department imposed export controls, which were lifted at the end of that month.

Anthropic releases Claude Opus 5 for both AI coding and general office work

Today Anthropic released its new Opus 5 model, which the company claims delivers performance comparable to its more advanced Fable 5 model at half the price. Opus 5 is designed for both complex coding and general office work. Anthropic says the model can make its way through the steps of a complicated problem without much back-and-forth with the user. Plus, it can check its own work and recover from errors rather than getting stuck. It also shows improvements over its predecessor, Opus 4.8, in complex coding tasks. The company calls it its strongest model yet for general knowledge work. A broader range of professional tasks The release is part of Anthropic's effort to expand Claude beyond chat and code generation, and into a broader range of professional tasks, including design, marketing, accounting, and the analysis of large document sets. What makes Opus 5 notable, however, is its proximity to Fable 5, the most advanced model Anthropic has made broadly available. Fable is significantly better than previous releases at writing software, working through long projects with limited supervision, and handling especially difficult assignments. The U.S. government even became alarmed at the model's capacity to discover and exploit software vulnerabilities in cyberattacks. (Fable 5 is the public version of another Anthropic model, Mythos 5, which is even better at cyber defense -- and offense -- and available only to the government and select organizations working on cybersecurity and critical infrastructure.)

Anthropic rolls out Opus 5 AI model in efficiency upgrade

The San Francisco-based lab said the new Claude AI model was well suited for daily office and computer programming tasks. Anthropic on Friday launched Opus 5, its latest AI ⁠model that ⁠the startup says nears the capabilities of its more powerful cousin Fable 5 at half the price. The San Francisco-based lab said the new Claude AI model was well suited for daily office and computer programming tasks. In an interview with Reuters, Anthropic product leader Dianne Penn said the release, more efficient than May's ⁠Opus 4.8, reflected a rapid pace of development. "We're building and continue to consistently deliver frontier intelligence and bring that as ⁠accessibly as possible with every model generation," said Penn. In testing, Opus 5 was less capable of exploiting cyber vulnerabilities than Anthropic's top-shelf AI, so its related safeguards are less restrictive than Fable 5's. Opus 5 was also less susceptible to being tricked into misuse than Anthropic's other current models, the startup said. Released in June, Anthropic's Fable 5 was temporarily unavailable following U.S. concerns that its capabilities could be diverted to foreign military intelligence. Users should pick Opus 5 for value and ⁠Fable 5 for "days-long, very autonomous projects," Penn said. Asked about the Kimi K3 "open" model from China-based Moonshot, which the U.S. accused of freeloading off Anthropic, Penn said it "remains to be seen" how open-weight models generally perform on complicated real-world projects that users ask Claude to tackle. Open-weight models allow users to download, run and customise the virtual brains of an AI, unlike proprietary models.

Anthropic Unveils Claude Opus 5, Says New Model Beats Rivals on Coding and Business Tasks

Anthropic has released Claude Opus 5, the latest version of its flagship artificial intelligence model, as the AI startup continues competing with OpenAI, Google and other major players for leadership in advanced AI systems. The company said Opus 5 delivers major improvements in software engineering, business automation and scientific research, with benchmark results showing the model outperforming competitors on several coding and knowledge-work evaluations. The launch comes as AI companies increasingly compete not only on model intelligence but also on efficiency and cost. Anthropic said Opus 5 can deliver stronger performance while using fewer resources, allowing customers to complete more complex tasks at a lower cost. Anthropic highlighted software development as one of Opus 5's biggest improvements, saying the model more than doubled the performance of Opus 4.8 on Frontier-Bench while lowering the cost per task. The company said Opus 5 also performed within 0.5% of its top competitor's peak score on CursorBench 3.2, a coding evaluation, while costing about half as much per task. Beyond coding, Anthropic said the model showed gains in business and productivity-focused applications. On Zapier AutomationBench, which measures whether AI systems can complete end-to-end business workflows, Opus 5 achieved a pass rate roughly 1.5 times higher than the next-best model at the same cost. The company also said Opus 5 outperformed other models on OSWorld 2.0, a benchmark designed to test AI agents' ability to interact with computers and complete tasks. Anthropic said the model has improved its ability to verify work, correct mistakes and complete complex projects with less human intervention. Anthropic Pushes AI Agent Capabilities The company pointed to examples from early users who tested Opus 5 on real-world tasks, including software development and financial technology projects. In one case, Anthropic said Opus 5 rebuilt a 3D machine part from an image by creating its own computer vision pipeline to extract the geometry. The company said competing models were unable to complete the same task under identical conditions. Anthropic also said an engineer at a trading firm used Opus 5 to build a market data feed for a new exchange, with the model creating its own testing framework when no live data source was available. Safety Remains a Focus Alongside performance improvements, Anthropic emphasized safety measures around Opus 5, saying the model demonstrated lower rates of problematic behavior during internal evaluations. The company said Opus 5 remains behind its more specialized Mythos 5 model in areas including offensive cybersecurity and advanced biology research. Anthropic said the model can identify cybersecurity vulnerabilities but is less capable of turning those vulnerabilities into exploits. The company also introduced additional safeguards for certain cyber-related tasks, including restrictions around penetration testing and exploit generation and is also offering a faster "Fast mode" option for users who want increased speed at a higher cost. This content was partially produced with the help of AI tools and was reviewed and published by Benzinga editors. Market News and Data brought to you by Benzinga APIs To add Benzinga News as your preferred source on Google, click here.

Anthropic launches Claude Opus 5 AI model at half the price By Investing.com

Investing.com -- Anthropic PBC introduced a new artificial intelligence model on Friday designed to handle workplace tasks at a lower cost as customer price sensitivity increases and competition grows in China. The company released Claude Opus 5, which it says delivers performance close to its most advanced model, Fable 5, in many areas while costing 50% less. Anthropic stated the new model is expected to become the default choice for many routine office tasks. Claude Opus 5 is priced at $5 per million input tokens and $25 per million output tokens, matching the cost of its predecessor, Opus 4.8, while offering improved performance. The model is available across all platforms starting Friday. The new model shows strong results on software engineering tasks. On Frontier-Bench v0.1, Opus 5 outperformed all other models and more than doubled Opus 4.8's performance at a lower cost per task. On CursorBench 3.2, the model achieved performance within 0.5% of Fable 5's peak score at maximum effort, but at half the cost per task. For problem-solving tasks, Opus 5 scored three times higher than the next-best model on ARC-AGI 3. On Zapier AutomationBench, which tests whether models can complete business tasks from start to finish, Opus 5's pass rate was approximately 1.5 times the next-best model for the same cost per task. The model also showed improvements for scientific research, scoring 10.2 percentage points higher than Opus 4.8 on organic chemistry tasks and 7.7 percentage points higher on protein-related tasks. In safety testing, Opus 5 scored 2.3 on overall misaligned behavior, the lowest among recent Anthropic models. The company said the model does not advance risky, dual-use capabilities and remains behind Mythos 5 in biology research and offensive cybersecurity. Opus 5 is now the default model on Claude Max and the strongest model on Claude Pro. The company also offers a Fast mode that runs approximately 2.5 times the default speed at twice the base price. This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.

Anthropic launches Opus 5, a more affordable and more secure AI model

Anthropic is positioning Opus 5 as a higher-performing evolution of Opus 4.8, released in May, aimed in particular at office tasks and software development. According to Dianne Penn, the product lead, this new generation reflects the company's rapid development pace, with the goal of making cutting-edge intelligence more accessible while maintaining a solid level of performance. Internal tests indicate that Opus 5 is less likely than Fable 5 to exploit cybersecurity vulnerabilities and is more resistant to manipulation attempts, allowing for less stringent protective measures. Fable 5, launched in June, was temporarily pulled after concerns from US authorities about the possible misuse of its capabilities by foreign military intelligence services. Dianne Penn says Opus 5 offers the best balance between performance and cost, while Fable 5 remains reserved for highly autonomous projects that can run for several days. Asked about Kimi K3, the "open-weight" model from Chinese company Moonshot, she also said it remains to be proven that open-weight models, which can be downloaded and customized by users, can effectively manage complex projects under real-world conditions.

Anthropic rolls out Opus 5 AI model in efficiency upgrade

SAN FRANCISCO, July 24 (Reuters) - Anthropic on Friday launched Opus 5, its latest AI model that the startup says nears the capabilities of its more powerful cousin Fable 5 at half the price. The San Francisco-based lab said the new Claude AI model was well suited for daily office and computer programming tasks. In an interview with Reuters, Anthropic product leader Dianne Penn said the release, more efficient than May's Opus 4.8, reflected a rapid pace of development. "We're building and continue to consistently deliver frontier intelligence and bring that as accessibly as possible with every model generation," said Penn. In testing, Opus 5 was less capable of exploiting cyber vulnerabilities than Anthropic's top-shelf AI, so its related safeguards are less restrictive than Fable 5's. Opus 5 was also less susceptible to being tricked into misuse than Anthropic's other current models, the startup said. Released in June, Anthropic's Fable 5 was temporarily unavailable following U.S. concerns that its capabilities could be diverted to foreign military intelligence. Users should pick Opus 5 for value and Fable 5 for "days-long, very autonomous projects," Penn said. Asked about the Kimi K3 "open" model from China-based Moonshot, which the U.S. accused of freeloading off Anthropic, Penn said it "remains to be seen" how open-weight models generally perform on complicated real-world projects that users ask Claude to tackle. Open-weight models allow users to download, run and customise the virtual brains of an AI, unlike proprietary models. (Reporting by Jeffrey Dastin in San Francisco; Editing by Sonali Paul)