With recent advances in AI, many technology firms and developers are exploring whether Generative AI (GenAI) tools can help improve productivity, code quality and the overall developer experience. Current evaluations primarily depend on subjective questionnaire data or code quality metrics. A supplementary objective, continuous, real-time, developer-centered measure is missing. Wearables with body sensors that measure the physiological activity of a person have the aforementioned benefits. Impeding factors from the GenAI tool on a developer’s well-being and cognitive load could be detected with the help of wearables. This research aims to use body sensor data to evaluate developer experience, productivity and GenAI interactions in real-life work environments. A holistic mixed-method approach by combining subjective and objective measures in a developer-centered manner is taken.