A computer program product for facilitating processing of operator message commands in a computing environment, said computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: obtaining, by a coupling facility of the computing environment from a source separate from, but coupled to the coupling facility, an operator message command and a token associated with the operator message command, the operator message command to specify, by the source, an action to be taken on the coupling facility to test whether the coupling facility is behaving as expected pursuant to the action, and wherein the source comprises a processor image, the processor image comprising one of: a logical partition having central processor resources and capable of executing an operating system and the coupling facility being within another logical partition having central processor resources and executing the coupling facility control code;or a stand-alone machine separate from the coupling facility; selecting, by the coupling facility, a buffer located within the coupling facility to store the token; storing, by the coupling facility, the token associated with the operator message command in the selected buffer located within the coupling facility; performing, by the coupling facility, the operator message command, the performing, comprising performing on the coupling facility the action specified in the operator message command received from the source to test the coupling facility, and placing information regarding the operator message command in the selected buffer; and providing, by the coupling facility, a response to processing the operator message command, the response to be available to the source of the operator message command, and characterised in that the obtaining comprises receiving the operator message command via a start operator message command initiated by the source, wherein the receiving comprises receiving the start operator message command at a multiplexor of the coupling facility, and in that the method further comprises selecting by the multiplexor the operator message command from one or more operator message commands to be processed and to forward the selected operator message command to an operator message processor of the coupling facility to process the selected operator message command. obtaining, by a coupling facility of the computing environment from a source separate from, but coupled to the coupling facility, an operator message command and a token associated with the operator message command, the operator message command to specify, by the source, an action to be taken on the coupling facility to test whether the coupling facility is behaving as expected pursuant to the action, and wherein the source comprises a processor image, the processor image comprising one of: a logical partition having central processor resources and capable of executing an operating system and the coupling facility being within another logical partition having central processor resources and executing the coupling facility control code;or a stand-alone machine separate from the coupling facility; selecting, by the coupling facility, a buffer located within the coupling facility to store the token; storing, by the coupling facility, the token associated with the operator message command in the selected buffer located within the coupling facility; performing, by the coupling facility, the operator message command, the performing, comprising performing on the coupling facility the action specified in the operator message command received from the source to test the coupling facility, and placing information regarding the operator message command in the selected buffer; and providing, by the coupling facility, a response to processing the operator message command, the response to be available to the source of the operator message command, and characterised in that the obtaining comprises receiving the operator message command via a start operator message command initiated by the source, wherein the receiving comprises receiving the start operator message command at a multiplexor of the coupling facility, and in that the method further comprises selecting by the multiplexor the operator message command from one or more operator message commands to be processed and to forward the selected operator message command to an operator message processor of the coupling facility to process the selected operator message command.