By combining neutron scattering data and DFT calculations we determine the gas adsorption sites and fully characterize the adsorption mechanism of CO and CO2 in the Fe(pz)[Pt(CN)4] Hofmann-type clathrate. When the MOF adsorbs 2 CO molecules per f.u. these orient parallel with each other and parallel to the Fe[Pt(CN)4]∞ but perpendicular with respect to the pyrazine rings. In contrast, when the uptake is 1.5 CO2 per f.u., the molecules adsorbed on top of the open-metal cation (site A) orient perpendicular to the pyrazines, while the molecule in the center of the pore (site B) are pseudo-parallel resulting in 'T'-shape configuration of neighbouring CO2. In both cases the guest molecules are parallel to Fe[Pt(CN)4]∞ planes. The main signatures of the INS spectra upon adsorption of 2 CO and 1.5 CO2 per f.u. occur in the peaks located at ca. 100 cm -1 and 400 cm -1 . The first blue-shifts upon CO and CO2 adsorption, with a larger shift for CO, while the second red-shifts only in the presence of CO. DFT calculations confirm these signatures and allow us to characterize the blue-shift as due to a hindered libration of the pyrazine and the out-of-plane movement of cyanide ligands when the gas is adsorbed. The red-shift of the peak at 400 cm -1 is caused by the steric effect of the guest when the pyrazines display a torsion movement. The DFT-predicted energy of the modes yielding the most intense INS features is studied with respect to the pore volume occupied upon adsorption by different amounts and types of gas. The predicted shift of these modes shows that those at ca. 107.9 and 403.6 cm -1 are the most sensitive upon volume and the nature of the gas. Consistent with a fully occupied d z 2 orbital of the Pt(II) that prevents a molecule/metal σ-donor/-acceptor interaction, the adsorption mechanism in both cases is of electrostatic and van der Waals nature (physisorption) with the latter dominating the binding. A weak backbonding metal-to-ligand charge transfer is predicted for the CO located on site A while no charge transfer was predicted for CO2. In conclusion, this work reports the gas adsorption mechanism of CO and CO2 in the Hofmann-like clathrate Fe(pz)[Pt(CN)4] for which large adsorption capacities were previously reported when compared to other MOFs with larger surface areas. We have made use of the information obtained from neutron diffraction, inelastic neutron scattering and density-functional theory calculations in a complementary way. The results suggest that only a few modes depend on the nature of the adsorbed gas and, although the use of these modes as a reference to selectively detect one gas over the other seems complicated, the experimental signatures are clearly different when the saturation points are reached.