An insert for a tool for assembling a bone anchoring device including a bone anchoring element with a head and a shaft to be anchored in bone and a receiving part, the insert configured for insertion into a holder of the tool, the insert including an elongate body with a longitudinal axis, wherein a first recess configured to receive a shaft of a bone anchoring element extends on a surface of the elongate body along the longitudinal axis, has a first diameter, and is oriented towards a first radial direction relative to the longitudinal axis, wherein a second recess configured to receive a shaft of a bone anchoring element extends on a surface of the elongate body along the longitudinal axis, has a second diameter greater than the first diameter, and is oriented towards a second radial direction relative to the longitudinal axis different than the first radial direction.