This disclosure relates to a working tool of a laparoscopic trainer having the form of a sleeve provided with a handle with a fixed arm and a movable arm with a rigid tie rod for manipulating the jaws of the working tip. The working tool includes a sensor unit detecting the opening of jaws of the working tip, housed within the handle of the working tool which comprises the first reflection sensor and the first reflector, wherein one of these elements of the opening sensor is attached to the handle of the working tool, and the other is mounted on the tie rod. This disclosure relates also to a manipulation and measurement set of a laparoscopic trainer, including a working tool according to the disclosure and a trocar, wherein the trocar has a guide channel for the slidable placement of the working tool therein.