This pilot study evaluated the feasibility, usability, and validity of mCAPP, a mobile, app-based cognitive assessment platform designed for at-home monitoring of patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) undergoing anti-amyloid therapies (AATs). Twenty-four older adults with MCI or AD completed mCAPP sessions featuring gamified tasks measuring memory, attention, processing speed, and executive function. Results showed that impaired participants demonstrated significantly slower response times and fewer correct responses than unimpaired participants across multiple conditions. Notably, impaired participants with higher prior digital engagement performed better on select tasks compared to impaired low-usage peers, suggesting that technology familiarity may impact performance. Overall, these findings support the initial reliability and validity of mCAPP as a remote tool for monitoring cognition in populations undergoing AAT.