Imagine a world where discovering new drugs and materials is not a painstakingly slow process, but one accelerated by the power of artificial intelligence. That's the promise of CACTUS, a cutting-edge AI agent poised to revolutionize chemistry and molecular discovery. Developed by researchers at Pacific Northwest National Laboratory, CACTUS (Chemistry Agent Connecting Tool-Usage to Science) isn't just another large language model (LLM). It's a clever chemist that combines the linguistic prowess of LLMs with the practical tools of cheminformatics. This means CACTUS can understand complex chemical queries, reason through problems, and even predict the properties of molecules, all while using tools like RDKit and SciPy and accessing databases like PubChem and ChEMBL. But what makes CACTUS truly special is its ability to connect these tools in a smart, efficient workflow. Like a seasoned researcher, it knows which tool to use when, streamlining the process of molecular discovery. The team tested CACTUS with a range of open-source LLMs, including Gemma-7b, Falcon-7b, and Mistral-7b, and found that it significantly outperformed baseline LLMs in accurately answering a diverse set of chemistry questions. Interestingly, even smaller, more accessible models like Phi2 and OLMo-1b showed promising results when run on consumer-grade hardware, suggesting that CACTUS's power could be available to a wider range of researchers. While challenges remain, such as optimizing prompt engineering and model deployment for various hardware, the future of CACTUS is bright. The team envisions CACTUS evolving into a comprehensive open-source tool for chemists, integrating advanced AI/ML models, 3D analysis, and even symbolic reasoning. This means CACTUS could not only predict molecular properties but also explain its reasoning, a crucial step towards building trust and understanding in AI-driven science. Beyond drug discovery, CACTUS holds potential for applications in catalysis and materials science, accelerating the design and optimization of new catalysts and materials with desired properties. CACTUS is more than just an AI; it's a collaborative partner for scientists, helping them navigate the complexities of chemical research and unlock new possibilities in molecular discovery.