## 1 Introduction and Background  
Parkinson's Disease (PD) is a chronic neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons, leading to both motor and non-motor symptoms [1]. Motor symptoms, such as tremors, rigidity, and bradykinesia, significantly impair the mobility and quality of life of those affected, while non-motor symptoms, including cognitive impairment, mood disturbances, and sleep disorders, further complicate disease management. Physical therapy and regular exercise play a crucial role in managing PD by maintaining mobility, improving balance, and enhancing the overall quality of life [1; 2; 3; 4]. Adherence to therapy is crucial for the success of any medical treatment. However, despite the proven benefits of physical activity, adherence to exercise regimens among people with Parkinson's disease (PwPD) remains a major challenge [5; 6]. Multiple barriers, including physical limitations, lack of motivation, and insufficient ongoing support, contribute to inconsistent engagement in prescribed therapeutic exercises. Recent advancements in digital health solutions, particularly mobile health (mHealth) platforms, have shown promise in addressing these barriers [7; 8; 9]. By providing patients with remote, personalized support, mHealth solutions aim to promote sustained engagement in therapeutic activities beyond the clinical setting. One such initiative, the MoveONParkinson project, was designed to enhance long-term exercise engagement among PwPD through the comprehensive digital platform ONParkinson, which includes both mobile and web interfaces for a broad, rich, personalized interaction [10]. The mobile interface (the mHealth app) is the primary interface for users (PwPD and their caregivers) to access exercise programs. The web platform provides healthcare professionals (HCPs) with access to clinical records and individual care plans, enabling them to create new exercises and programs, monitor their patients' performance, and provide feedback. By optimizing therapy outside of the clinical context, the platform aims to provide remote support for HCPs as a complement to the mHealth app. In addition to enhancing and evaluating the interfaces and functionalities of the exercise module, the MoveONParkinson project sought to integrate advanced features into the platform. These enhancements included targeted gamification elements using technologies like Virtual Reality to increase engagement [11], the integration of biometric data-reading devices for more accurate and efficient remote monitoring, and the development of a conversational agent (CA) to support PwPD in maintaining their exercise routines. CAs are software systems designed to simulate human-like conversations, often leveraging artificial intelligence to provide personalized interactions in various domains, including healthcare [12]. These agents are also commonly referred to as chatbots in casual and technical contexts, especially when deployed on mobile or web platforms. For consistency, this paper uses the terms conversational agent and chatbot interchangeably. The use of CAs in healthcare is rapidly expanding, enabling more natural, human-like interactions. CAs serve roles in diagnostics, education/training, and monitoring/data collection [12; 13; 14], while also providing emotional support and motivational coaching, particularly valuable in chronic disease management and mental health [15; 16]. Recent studies illustrate their potential in intervention for managing chronic illness: [PERSON] et al. [17] showed AI chatbots for genetic counseling matched the effectiveness of traditional methods, while [PERSON] et al. [18] found chatbots rated more favorably than physicians for providing information to breast cancer patients, despite needing improved adverse eventcommunication. [PERSON] et al. [19] demonstrated that TensioBot enhanced knowledge of blood pressure self-monitoring. For chronic pain, [PERSON] et al.