In summary, we report a chemo-mechanical approach to decrease failure probability in brittle garnet solid electrolytes by annealing 3-nm Ag coating. Depth profiling indicates the complete incorporation of Ag + into the LLZO subsurface via Ag-Li ion exchange, consistent with thermotical predictions. The Ag + -LLZO surface exhibits enhanced tolerance against Li intrusion compared to the uncoated LLZO, as evidenced by improved local current density and expanded electroplating area. Nanoindentation experiments reveal a substantial surface toughening that accompanies Ag + doping into LLZO, taking place both in the bulk and along grain boundaries.