Solar Pro 2 (Preview) (Reasoning) is a large language model developed by Upstage AI, featuring a 31-billion parameter architecture. As the successor to the original 22B Solar Pro, it is designed to bridge the gap between compact models and frontier-scale performance. It introduces a hybrid architecture that allows users to switch between a standard "Chat Mode" for rapid interaction and a specialized "Reasoning Mode" for structured, multi-step problem solving.
The model utilizes Chain-of-Thought (CoT) reasoning to enhance its performance in complex logical domains such as advanced mathematics, software engineering, and multi-hop queries. By leveraging Upstage's proprietary Depth-Up-Scaling (DUS) methodology, Solar Pro 2 achieves benchmark results competitive with models more than twice its size, while remaining optimized for resource-efficient deployment.
In addition to its reasoning capabilities, the model provides strong multilingual support, with specific optimizations for Korean, English, and Japanese. It is capable of executing agentic tasks through tool integration and features an expanded context window of 65,536 tokens, facilitating the processing of long-form documents and extended conversations.