An endoscope including an insertion tube, a working, channel located within the insertion tube, and a protecting feature disposed within at least a portion, of the working channel The protecting feature may be adapted to protect the working-channel from thermal damage and/or from mechanical damage caused by a medical instrument located in the working channel. The protecting feature may be adapted to determine presence or absence of a medical instrument within the working channel, arid/or a location of the medical instrument within the working channel.