Upstage unveils Solar Open 2, open-weight AI model built for autonomous tasks

Upstage, a Korean artificial intelligence (AI) company, said Thursday it has released Solar Open 2, an open-weight large language model designed to complete multistep tasks rather than simply answer questions.

The company published the model's weights, the underlying parameters that determine how the AI processes information, on Hugging Face, a global open-source platform, along with a technical report detailing its architecture and training methods.

The model was developed under a government-backed project to build Korea's own foundation AI models, in which Upstage serves as the lead organization.

Solar Open 2 has 250 billion parameters but activates only 15 billion at a time, using a "mixture of experts" structure that Upstage said makes it more efficient for token-heavy agent tasks.

It can process up to 1 million tokens of context and, when compressed through quantization, can run on two Nvidia H200 chips.

The company said the model outperformed DeepSeek's V4 Flash, Mistral's Medium 3.5 and Cohere's Command A+ on benchmarks measuring instruction-following, tool use and overall agent p ...