IK error tolerance settings in Bongo document properties adjust how accurately IK constraints are held up. Higher number means less accuracy and more wobble. Smaller number means more accuracy and less wobble.
Translation, rotation and scaling have their own tolerance, translation and rotation tolerance are absolute and scaling tolerance is relative. Tolerances are used per axis – each component can have that much error. Setting the translation error to 0.1 means that the constraint object is allowed to be 0.1 units away from the goal along any axis. So it should stay inside a cube centered at the goal and whose sides are 0.2 units.