Abstract
<jats:p>Initial structure generation is the universal first step in computational chemistry but remains a bottleneck as each class of structures requires a different structure preparation workflow. We present an open-source UniversalStructure Generator(USG) based on artificial intelligence (AI) that converts natural-language prompts into molecular structures for both molecular and matter simulations, enabling rapid workflow development and seamless agentic AI integration. Computational and theoretical chemistry have recently transitioned into essential parts of modern chemical research. They serve multiple purposes such as supporting experimentally observed behaviour, enabling high-throughput screening before selecting top candidates for synthesis, and revealing underlying mechanisms. Regardless of the research direction or the problem being addressed, the first step in any simulation always remains the same: constructing the initial structure of the system.</jats:p>