The accuracy of the MLFF on phonon dispersions and vibrational free energies for a selected set of training structures are shown in Fig. , and for pure Ag and Pd in Fig. . The agreement with DFT values is similar to that of Na 1 -x K x Cl. Again, we note that the error in vibrational free energy is larger for the end-members, although visually the phonon dispersions are in very good agreement. Thus, we will again simulate the phase diagram both with and without end-members constrained to DFT values. A comparison of DFT (+F vib ) and CE energies is shown in Fig. including their cross-validation RMSE. Compared to the Na 1 -x K x Cl case, only a very small stabilisation of the mixed phases from the inclusion of vibrational contributions is observed here.