We evaluated mbGDML, mbGAP, and mbSchNet on tetramers (4mers), pentamers (5mers), and hexamers (6mers) from the literature. These test structures have minimal higher-order (> 3-body) contributions that increase with the number of monomers. Furthermore, many-body ML (mbML) potentials considered here implement a distance-based cutoff for 2-and 3-body contributions (see the ESI for more details). Small clusters allow us to determine whether errors are from the underlying MBE framework or ML predictions.