A downhole tool actuation system has a fluid path defined by a bore formed within a tubular body of a tool. A reciprocating sleeve is located within the bore and the sleeve has a segmented seat with a fluid by-pass. At least one seat segment is positioned by an outer diameter of the sleeve to complete the seat, and a relief is formed in a wall adjacent the outer diameter of the sleeve. When the seat is occupied by an obstruction, only a portion of the fluid path is obstructed and fluid impinging the obstruction causes the sleeve to move in the direction of flow until the at least one segment is relieved by the relief thereby releasing the obstruction.