BACKGROUND: Ventriculostomy is a widely performed neurosurgical procedure; some risk factors can be mitigated by computer/robot-assisted approaches. Platforms fostering synergistic robot–surgeon integration are pursued, for which lightweight robots with compliant controlled joints must be assessed (because compliance hampers accuracy). METHODS: We developed a platform encompassing, in particular, a lightweight robot and an optical tracker also used to enhance robot accuracy. Based on specifications by neurosurgeons, we designed a neuroendoscope-handling interface and assessed targeting accuracy in a model ventriculostomy where the robot was operated both autonomously and in hands-on (i.e. co-operative) mode. RESULTS: Targeting errors were systematically below the procedure accuracy threshold (1 mm); the rms targeting errors were 0.51 and 0.54 mm for autonomous and hands-on control, respectively. No significant difference was observed between the considered control modes. Very positive feedback was gathered from neurosurgeons. CONCLUSIONS: Accurate tool targeting under both autonomous and hands-on control was achieved. Copyright © 2015 John Wiley & Sons, Ltd.