Anthropic releases Claude Sonnet 4.5, a model it says can build software and accomplish business tasks autonomously

Dario Amodei, sitting in a white chair in front of a pink background on stage, puts both hands out in front of him, gesturing. (Credit: Chance Yeh—Getty Images for HubSpot)

Anthropic has launched Claude Sonnet 4.5, its newest AI model, claiming significant advancements in autonomous work and coding.

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 improvement over the company’s previous Opus 4 model, released four months ago, which could operate autonomously for only seven hours.