Implementations described and claimed herein provide systems and methods for delivering and retrieving a leadless pacemaker. In one implementation, a leadless pacemaker has a docking end, and the docking end having a docking projection extending from a surface. A docking cap has a body defining a chamber. The docking cap has a proximal opening into the chamber. The proximal opening is coaxial with a longitudinal axis of a lumen of a catheter. A retriever has a flexible grasper with a first arm disposed opposite a second arm. Each of the first arm and the second arm form a hinge biased radially outwards from the longitudinal axis. The docking cap locks the first arm and the second arm on the docking projection when the body is sheathed over the retriever until the flexible grasper is disposed within the chamber.