A Klingon scout ship was a starship utilized by the Klingons for scout missions. Klingon B'rel-class bird of prey's were classified as scout ships. (Star Trek III: The Search for Spock)
In 2369, a Klingon scout ship visited Deep Space 9, where it was placed at docking bay eleven. The presence of the ship, and her crew, had Odo on edge. Following her departure Benjamin Sisko looked forward to telling Odo the news so that the security chief could relax. (DS9: "Q-Less")
In 2374, General Martok sent several scout ships to the Cardassian border. They found no sign of Dominion activity. (DS9: "Resurrection")