An bipolar electrosurgical tool (10) for cauterizing or ablating tissue. The tool has a nose cone (12) which serves as a handle. A conductive shaft (14) extends from the nose cone. A tip assembly (18) with an active electrode (20) is mounted to the shaft. A circuit board (78) is mounted in the nose cone. Conductive traces that forming contact pads (96, 102) are formed on the circuit board. A web (108) formed from a single piece of elastomeric material is seated over the opening in which the printed circuit board is mounted to seal the opening shut. Integrally formed with the web are buttons (116, 118) that are in registration over the contact pads. The buttons can be depressed downwardly towards the contact pads. When a button is so depressed, a conductive landing pad (120) integral with the button closes the connection between the traces that form the contact pad. Thus, the tool of this invention is provided with switches. The circuit board also has two conductive traces (92, 104a) that run in parallel. If there is a leak into the nose cone, a connection is established across these traces and shorts out a resistor (105). The shorting out of this resistor provides a control console (22) with an indication that there is a leak. The electrode is formed from a single piece of tantalum. The electrode has a head formed with a hole (172) trough which fluid flows. The electrode is seated in a sleeve (136b) provided with a through bore (177) in registration with the electrode hole.