New Claude 4 AI model refactored code for 7 hours straight
Anthropic says Claude 4 beats Gemini on coding benchmarks; works autonomously for hours.

On Thursday, Anthropic released Claude Opus 4 and Claude Sonnet 4, marking the company's return to larger model releases after primarily focusing on mid-range Sonnet variants since June of last year. The new models represent what the company calls its most capable coding models yet, with Opus 4 designed for complex, long-running tasks that can operate autonomously for hours.
Alex Albert, Anthropic's head of Claude Relations, told Ars Technica that the company chose to revive the Opus line because of growing demand for agentic AI applications. "Across all the companies out there that are building things, there's a really large wave of these agentic applications springing up, and a very high demand and premium being placed on intelligence," Albert said. "I think Opus is going to fit that groove perfectly."
Before we go further, a brief refresher on Claude's three AI model "size" names (introduced in March 2024) is probably warranted. Haiku, Sonnet, and Opus offer a tradeoff between price (in the API), speed, and capability.