AI·ModelsAnthropic releases Claude Sonnet 4.5, a model it says can build software and accomplish tasks autonomouslyBy Beatrice NolanBy Beatrice Nolan ReporterBeatrice Nolan ReporterBeatrice Nolan is a reporter on Fortune’s AI team, covering artificial intelligence and emerging nologies and their impact on work, industry, and culture.
She's based in Fortune's London office and holds a bachelor’s degree in English from the University of York.
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The company said that the model was able to run autonomously for 30 hours, maintaining sustained focus with minimal oversight while building an entire software application.
It’s a significant imvement over the company’s previous Opus 4 model, released four months ago, which could operate autonomously for only seven hours.
Anthropic said Claude Sonnet 4.5 also outperformed Opus on key benchmarks and was more effective in meeting customers’ practical needs.
The company said the model was even better at coding than previous frontier models, and state-of-the-art on SWE-Bench Verified, a key benchmark that tests how models perform at software development tasks.
Anthropic said that Claude Sonnet 4.5 was better than its predecessors at ing instructions, identifying code imvements, and generating more duction-ready code.
When tested on tasks from the financial services industry, the company said the new model outperformed earlier Claude models in tasks such as reing, building financial models, and forecasting.
Anthropic appears to be pushing further ahead of its competitors in coding assistance and autonomous task completion, positioning its models toward corporate and workplace use.
The company’s previous Claude Opus 4.1 model already bested competitors on OpenAI’s new benchmark of fessional task completion, GDPval, which tested how models performed compared with human fessionals across a range of industries and jobs.
Last week, OpenAI said its GPT-5 model and Anthropic’s Claude Opus 4.1 were “already apaching the quality of work duced by industry experts.” Dueling usage studies released earlier this month also suggested that Anthropic’s Claude models were emerging as more fessionally oriented AI models, especially in comparison with OpenAI’s ChatGPT, which is increasingly being used as a consumer duct.
According to the study, most Claude users were turning to the models for workplace or ductivity tasks, with mathematical tasks and coding cited as the dominant activities globally for Claude.ai, and making up 36% of all use cases.
use of Claude leaned heavily toward task automation.
According to the study, apximately 77% of mpts that the model receives through its API—the application gramming interface that is primarily used by enterprise customers—involves users requesting the system to perform tasks on their behalf, rather than just viding advice or suggestions.
These -focused interactions are also concentrated in coding, which accounts for 44% of API use. A further 5% of API usage was dedicated to or evaluating AI systems.
The tasks that users automate also tend to be the most expensive ones to run. The findings indicate a shift in how es apach these tools.
Rather than using them mainly for decision support or re, many teams are relying on them to take work off their plates entirely.
If models Claude are able to become more capable of autonomous work, especially in complex, time-intensive domains software engineering, the implications for es and employees could be significant.
Autonomous agents can reduce the need for constant human oversight and lower costs on repetitive workflows, speeding up a company’s operations and potentially reducing the need for headcount.Fortune Global Forum returns Oct.
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