Abstract: Suicide is a leading cause of death among active-duty military personnel. Although specialty mental health services are readily available, primary care clinics represent the most frequently accessed clinical setting immediately preceding suicide deaths and suicide attempts among service members. Primary care clinics offer a critical and unique opportunity to implement interventions targeting suicide prevention. Effective engagement and response to servicemembers with elevated suicide risk requires scalable alternatives to traditional mental health care. The central focus of this study is to test the efficacy of Aviva, a scalable, digital adaptation of Brief Cognitive Behavioral Therapy for Suicide Prevention in three primary care clinics with active-duty military servicemembers in comparison to treatment as usual. This paper describes the design, methodology, and protocol of an active randomized controlled trial comparing Aviva to treatment as usual. The impact on subsequent suicidal ideation and behaviors during a year-long follow-up period will be evaluated. Clinical Trial Registration: NCT06318962