Systems, devices and methods are provided for endoscopic procedures involving tissue manipulations beyond the capabilities of traditional endoscopic instruments. Embodiments of the systems include an elongated main body having a scope therethrough and at least one steerable tool arm which extends from the distal end of the main body. In preferred embodiments, the system includes two tool arms, each arm steerable to form a curve laterally outward which then bends laterally inward so that the arms form an angular shape. In addition, end effectors extend from the distal ends of each tool arm for use in manipulation of tissue. The angular shape brings the end effectors together in view of the scope for cooperative movements which are continuously visible by the surgeon. In addition, the tool arms may be steerable in any additional direction and may be rotateable to allow grasping, elevation and more complex manipulation of tissue.