Robotic surgical tool with drop in instrumentation core

A robotic surgical tool comprises a stage assembly and a core assembly removably mountable to the stage assembly. The stage assembly may comprise a lead screw and at least one spline extendable between first and second ends of the stage assembly, and a nut rotatably mounted to the lead screw to translate between the first and second ends upon rotation of the lead screw. The core assembly may comprise a drive housing that is movably mountable to the stage assembly to translate, with the nut, between the first and second ends of the stage assembly. The surgical tool may also comprise a shroud assembly having a primary shroud and a secondary shroud, the primary shroud at least partially enclosing the core assembly when installed on the stage assembly, and the secondary shroud being movable between a first position, where the secondary shroud occludes an opening in the primary shroud, and a second position, where the opening in the primary shroud is exposed. The secondary shroud may be pivotally attached to the primary shroud at a hinge. The secondary shroud may be slidingly attached to the primary shroud, such that the secondary shroud is circumferentially revolvable relative to the primary shroud between the first and second positions. The secondary shroud may be slidingly attached to the primary shroud, such that the secondary shroud is axially slidable relative to the primary shroud between the first and second positions.