When the ToolTalk service determines that a message needs to be delivered to a specific process, it creates a copy of the message and notifies the process that a message is waiting. If a receiving application is not running, the ToolTalk service looks for instructions (provided by the application at installation time) on how to start the application.
The process retrieves the message and examines its contents.
If the message contains a notice that an operation has been performed, the process reads the information and then discards the message.
If the message contains a request to perform an operation, the process performs the operation and returns the result of the operation in a reply to the original message. Once the reply has been sent, the process discards the original message.