Example implementations relate to generating instructions for robotic tasks. A method may involve determining task information of a path-based task by an end-effector on an object, where the task information includes (i) at least one task parameter, and (ii) a nominal representation of the object. The method also involves based on the task information, determining one or more parametric instructions for the end-effector to perform the task, where the one or more parametric instructions indicate a toolpath for the end-effector to follow when performing the task. The method also involves generating, based on sensor data, an observed representation of the object, and comparing the observed and the nominal representations. The method further involves based on the comparison, mapping the parametric instructions to the observed representation of the object. The method yet further involves sending the mapped instructions to the end-effector to cause the robotic device to perform the task.