1. 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: executing a send message instruction by a processor image of the computing environment, the executing comprising: selecting a subchannel for determining a path to a coupling facility coupled to the processor image; and sending a send message command block to the coupling facility, the send message command block comprising a start operator message command block for a start operator message command, the start operator message command block including an operator message token uniquely associating an operator message command with a buffer of the coupling facility, the buffer including a plurality of fields to be populated responsive to executing the start operator message command, the plurality of fields including a timer field, an operator message request length field, an operator message response length field, an operator message command field, an operator message token field to include the operator message token and a response field; and wherein the sending of the send message command block comprises sending the start operator message command to the coupling facility for processing at the coupling facility.