The company confirmed that Opus 4.5 provides leading results in software engineering tests, becoming the first model to clear the 80% mark on the SWE-Bench Verified assessment. 

It also recorded success in problem-solving tasks and computer-based performance, areas Anthropic has pushed aggressively in recent months.

Alongside the launch, the company is enhancing access to several products built around the model’s capabilities. Claude for Chrome will now be open to all Max users, while Claude for Excel is expanding to Max, Team and Enterprise customers. These tools were previously restricted to pilot testing.

Opus 4.5 introduces a redesigned memory system intended to improve long-running tasks and reduce disruptions during extended conversations. Users with paid plans will now be able to continue chats without being cut off when the system reaches its context limit, as the model compresses earlier exchanges quietly in the background.

Dianne Na Penn, Anthropic’s head of product management for research, noted the change in how the system handles information, saying: “There are improvements we made on general long context quality in training with Opus 4.5, but context windows are not going to be sufficient by themselves. Knowing the right details to remember is really important in complement to just having a longer context window.”

Anthropic has also framed the update as preparation for more advanced agent-style tasks, where Opus directs smaller models to complete complex work across documents and codebases. 

Penn noted the need for stability in those scenarios, adding: “This is where fundamentals like memory become really important, because Claude needs to be able to explore code bases and large documents, and also know when to backtrack and recheck something.”

The release arrives during a crowded period in the sector, coming less than two weeks after OpenAI launched GPT 5.1 and shortly after Google rolled out Gemini 3 on November 18. All three companies are competing for enterprise customers seeking systems capable of specialised technical work.

Opus 4.5 is available through Anthropic’s apps, API and major cloud platforms. The company has also increased usage allowances for Max and Team Premium customers to support daily adoption.

Anthropic says more details on performance and safety testing are outlined in its system documentation, which states that Opus 4.5 is the most secure model the firm has produced so far.

The company announced the research preview on Tuesday, saying that 1,000 subscribers on its Max plan, priced between $100 and $200 per month, will be the first to gain access. A waitlist is also open for others.

Through a Chrome extension, selected users can summon Claude in a sidebar window that stays in sync with their browsing activity. The agent can summarise pages, interact with content, and, when granted permission, even perform tasks inside the browser.

The browser is quickly becoming a focal point in the competition among AI developers. Perplexity recently released its own AI-powered browser, Comet, while Google has integrated Gemini into Chrome, and OpenAI is reportedly working on its own AI-driven browser. 

These reveal browsing has gone beyond search to handing over routine actions to automated systems.

For Anthropic, the launch is also about safety. The company admitted that browser-based agents carry real risks, including prompt injection attacks, where hidden instructions in a web page could trick the AI into carrying out harmful commands. 

Internal testing showed such attacks succeeded 23.6% of the time before mitigations. Anthropic now claims it has cut that rate to 11.2% by introducing several layers of defence.

Among them are site-level restrictions, default blocks on financial services, adult, and pirated content, and mandatory confirmations for sensitive actions such as publishing, payments, or sharing personal data. “Claude will always ask for explicit permission before taking high-risk actions,” Anthropic said in its blog post.

Google’s Chrome browser, which tops global market share, is at the centre of an antitrust case that could force the company to sell the product. If that happens, ownership of Chrome could reshape the competitive landscape. 

Perplexity has already placed an unsolicited $34.5 billion bid for Chrome, while OpenAI’s Sam Altman has said his company would also be willing to buy it.

This isn’t Anthropic’s first attempt to give its models control over a user’s screen. Last year, the firm tested a desktop-based agent that could operate a PC, but the early version was criticised for being sluggish and inconsistent. 

Since then, the “agentic AI” has advanced considerably, with systems like Comet and ChatGPT’s Agent showing more reliability in handling everyday digital tasks, even if they continue to struggle with more complex scenarios.

Analysts see Anthropic’s decision to limit Claude for Chrome to premium subscribers as a sign of where the industry is heading: towards new business models built around productivity tools, enterprise automation, and personalised web experiences. 

Gartner has projected that the AI security market could reach $15 billion by 2027, driven largely by demand for safe, agentic systems.