Upgraded Retractable Baby Gates for Stairs & Banister, Mesh Dog Gate Indoor, Extends to 55" Wide 33" Tall, Child Safety Gate for Stairway, Banister & Wall Mount (Black)

They make these retractable baby gates that have flat boards that you can strap to the posts… we had one at the bottom of our stairs, worked great (ours was white) I would not do it at the TOP of the stairs though, for that I got a heavy duty metal gate that I screwed in to the posts…that was way safer.