Our version of RAG, illustrated in (1) in Fig. , uses a database of two documents that we considered useful context: the ORCA manual and the ORCA Input Library website . Such a documentation-based version of RAG has previously been shown to be effective for code synthesis . The manual is the main documentation for ORCA. It provides extensive and authoritative information on the available functionalities, commands, and parameters. We used all pages except for the parts where keyword and option definitions were provided. We excluded these because they were already used to construct our user prompts. Hence, including them could inflate model performance artificially if the model learned to rely on direct overlaps between the prompts and documentation. By omitting this data, we ensure a more realistic performance evaluation. In addition, the ORCA Input Library offers a comprehensive overview of the possible calculations in ORCA. It contains many practical examples and input file templates as guidance for users. To be able to use it as a document, we saved all its pages as PDF.