A method for operating a coring tool includes moving a handling piston of a coring tool from a first position to a second position with respect to the coring tool where the handling piston moving through a coring bit to the second position. The method also includes measuring the distance of the movement of the handling piston between the first position and the second position to determine a core length, comparing the measured distance with a predetermined threshold, and operating a coring bit of the coring tool to obtain a core sample in response to determining that the measured distance is less than the predetermined threshold.