We interpret the significant expansion of the plated area at failure as an improved surface defect tolerance attributed to Ag + surface doping (rather than elevated electronic conductivity), enabling a larger current density before failure even in the presence of nanoscale mechanical defects generated by indentation. In-situ nanoindentation (n=69) quantifies a substantial increase in the loading force necessary to fracture the surface of Ag + -LLZO from 5.7 ± 1.5 to 27 ± 3.1 mN compared to the uncoated LLZO, indicating significant surface toughening. This study demonstrates that nanoscale heterogenous doping is a promising strategy for effectively controlling Li electroplating behavior.