The metallic classification task can be rationalised by an important caveat that this task is based on Materials Project 31 data. This classification is based on the band gap calculated with semi-local density functional theory, so it is possible that some of the compounds in this dataset that are labelled as metals could in fact be semiconductors due to a band gap underestimation at this level of theory . Additionally, it is likely that many known metallic compounds are likely to have been excluded from the construction of the dataset. This occurred due to the need to assign oxidation states to materials, which typically leads to the exclusion of many intermetallic com- pounds.