PROJECT SUMMARY Substance use disorder (SUD) is a significant public health challenge, and it has been estimated that its effects on healthcare, work productivity, and criminal justice costs the US over $600 billion annually. Engagement with the clinical care team is critical to an individual’s path to SUD recovery; however, limited capacity of and access to addiction treatment providers and trained staff presents an even greater challenge when faced with an increasing demand for care. Our proposed innovation, Suzy, is a novel and intelligent chatbot designed to provide usable, engaging, on-demand follow-up support for individuals in long-term SUD recovery guided by their clinical care team. In this Phase II work, we will evaluate effectiveness and implementation of Suzy with primary care patients working closely with recovery coaches who play a critical role in following up with and engaging patients in care. We will use a mixed methods approach to evaluate effectiveness and implementation of Suzy following three specific aims: In Aim 1, we will follow a human-centered design approach to build a fully functional enhanced HIPAA-compliant chatbot. In Aim 2, we will conduct a single-group mixed methods interventional study (Study 1) with patients to evaluate Suzy’s effectiveness and implementation. In this aim, primary care patients will be enrolled with Suzy and complete baseline, weekly, and endline assessments over the course of a 12-week intervention period. A purposive sample of patients and their recovery coaches will participate in qualitative interviews to collect perspectives on Suzy user experience and patient care. In Aim 3, we will assess sustainability and conduct cost analyses (Study 2) for the system. Results of this Phase II project will inform further development and adoption of a cost-effective, scalable solution built on a community-based model of care to support continuing care for individuals beyond SUD treatment and in pursuit of long-term health and wellbeing.