Extending retarget

Plugin-style extension points keep the core small. Pick the guide that matches what you are adding:

Guide	When to use it
Add a Robot	New RobotSpec, kinematics layout, joint limits
Add a Kinematics Backend	MuJoCo-style FK, Jacobians, integration
Add a Motion Format	Loaders for new motion file layouts
Add an Objective or Constraint	Custom optimization terms

Protocols and registries are documented in the API and Registries sections.

Every registry requires a member of its extensible enum-key base. Define a project enum such as LabRobot(RobotKind) or LabObjective(ObjectiveKind), then pass that member to register() and get(). Raw strings are accepted only at config and CLI deserialization boundaries.

Spec and factory registries (robots, motion_formats, kinematics_backends, solver_factories) accept direct values or factories. Protocol registries (motion_loaders, objective_terms, constraint_terms, exporters, and visualizers) validate decorated implementations at registration time.