Well, you're not going to be able to "read" this in an action (or custom command), because custom commands issue commands to a device, not read the state of devices. Like I said, if you "reading" it in the action of a rule, what are you going to do with that? There's no were for you to store it and no way to respond to it. It would have to be in the If part of the rule for you to do anything with it. But the device's status is not exposed to Rule Machine...only that standard set of capabilities.
Check out this post. This app might be what you are looking for.
