How much work does the tension force do on magnus?

The work done by the tension force on Magnus depends on the direction of the tension relative to Magnus's displacement. If the tension force acts in the same direction as Magnus's movement, it does positive work, increasing his energy. Conversely, if the tension acts against his direction of motion, it does negative work, reducing his energy. To quantify this, one would need specific values for the tension force, the displacement, and the angle between them.