Ag/MAX electrical contacts show great potential for low-voltage switching applications. However, the influence of MAX phase structural characteristics on interfacial diffusion, material transfer behavior, and nanomechanical evolution of Ag/MAX composites under arc erosion remains unclear. In this study, Ag/Ti₃AlC₂ and Ag/Ti₂SnC composites were fabricated, and their interfacial evolution, material transfer behavior, and nanomechanical degradation during arc erosion were systematically investigated. The results reveal that the structural differences between Ti₃AlC₂ and Ti₂SnC significantly affect the arc-induced degradation behavior of Ag/MAX composites. Due to the weaker Ti-Sn bonding, Ti₂SnC exhibits higher interfacial reactivity at elevated temperatures, promoting Sn diffusion into the Ag matrix and enhancing interfacial bonding, thereby suppressing molten Ag migration and reducing material loss. In contrast, Ti₃AlC₂ with stronger Ti-Al bonding maintains higher structural stability during arc erosion, resulting in less structural decomposition and superior nanomechanical retention after erosion. This work establishes the relationship between MAX phase bonding characteristics, arc-induced interfacial diffusion, material transfer behavior, and nanomechanical evolution, providing insights into the design and optimization of high-performance Ag/MAX electrical contact materials.