Anthropic says Claude Opus 4 is its most powerful model and the best coding model in the world, while Sonnet 4 is replacing Sonnet 3.7 in the chatbot.

Anthropic has rolled out Claude 4 Sonnet and Claude 4 Opus to its users, bringing a host of upgrades to the AI models running its chatbot.

Claude 4 Sonnet is a leaner model, with improvements built on Anthropic's Claude 3.7 Sonnet model. The 3.7 model often had problems with overeagerness and sometimes did more than the person asked it to do, Amodei said. While it's a less resource-intensive model, it still performs well, he said.