We evaluated the consistency and accuracy of state-of-the-art LLMs for forward reaction prediction. The models assessed include GPT-4 13 , GPT-4o 16 , o1-preview, o1-mini 17 , Claude To guide the models, we provided explicit instructions tailored to the input and output molecular representations. For instance, when both the input and output were in SMILES format, the instruction read: "Based on the SMILES strings of reactants and reagents, predict the SMILES string of the product. Please output the product directly."