CAF is also designed for extensibility. The list of properties used for calculating features can be further enhanced by incorporating novel size or electronegativity scales defined by the user. For instance, the size scale is sensitive to the class of materials and the presence of other elements, making it advisable for users to calculate their own scale for effective modeling. For example, to define a new size scale, one could use the shortest homoatomic distance from CIF reports, divided by 2, to determine the CIF radius. We recommend generating the output with the mean value, standard deviation, and a histogram for visual inspection. The CIF radius scale can then be used as a property for feature definition, comparable to other metrics such as covalent radius, ionic radius, and others.