Abstract: An apparatus and method for indicating the operational status of equipment (“tools”) used in semiconductor fabrication is provided. In one embodiment, the operational status of a tool is indicated by a mechanical sign attached to the tool. The sign contains indications of multiple operational statuses of the tool. The current operational status is indicated by covering the other possible operational statuses. The sign is constructed of materials that are compatible with the semiconductor fabrication environment. In a second embodiment, the operational status of a tool is indicated by illuminating a light. Lights for indicating possible operational statuses of the tool are attached to the tool. The lights may by illuminated by depressing a switch. Alternatively, the illumination of the lights may be controlled by a computer that also controls the operation of the tool. The computer may also cause an indication of the tool's operational status to be indicated on a monitor attached to the tool.