MedDr medical copilot is an AI system that supports medical education and real-world clinical consultation through a generalist–specialist collaboration (GSCo) framework. At its core, MedDr serves as a strong generalist medical foundation model capable of instruction-following and in-context reasoning, and it can be deployed in multiple roles: (1) as a virtual patient for consultation skills training and OSCE-style practice; (2) as a patient-facing intake agent in the waiting room to collect structured histories and symptoms; (3) as a triage assistant that helps route cases and prioritize urgency; and (4) as an in-consultation copilot that helps understand doctor – patient dialogue and generate clinical documentation. The system is enhanced by Mixture-of-Expert Diagnosis (MoED) to integrate specialist model insights and Retrieval-Augmented Diagnosis (RAD) to surface similar cases and relevant context for more grounded decision support.