The goal of this clinical trial is to compare the efficacy, ergonomics, and safety of robotic versus manual flexible ureteroscopy (fURS) for kidney stone treatment in adult patients undergoing laser lithotripsy. * Does robotic-assisted lithotripsy using the ILY® robot have the same efficacy as the manual fURS in treating kidney stones? * Is robotic flexible ureteroscopy associated with similar or improved safety outcomes, including perioperative and 30-day postoperative complication rates? * Does the robotic system offer improved ergonomics, lower surgeon radiation exposure, and favorable intraoperative metrics compared to manual flexible ureteroscopy? Researchers will compare the ILY robotic system with manual fURS to see if robotic intervention can match or improve clinical and ergonomic outcomes. Participants will: * Be randomly assigned to undergo laser lithotripsy with either the ILY robot or manual flexible ureteroscopy * Complete standard pre- and postoperative assessments * Undergo evaluation for stone-free status using a non-contrast CT scan at 30 days postoperatively * Undergo evaluation for postoperative complications