How can I tell for sure if a device connected to my C-7 Hub is a repeater or not? I'm not looking for rules of thumb (e.g. if the device is powered from an AC outlet it's probably a repeater), nor is any definitive manufacturer documentation available.
I'm not sure you can see this information on Hubitat anywhere, but Z-Wave PC Controller with a secondary controller (assuming you aren't using a C-5 or earlier with an external stick already; then you could just use that) would show you. You can tell if a device is "listening" or not (with some work) from the hub, but that includes some non-repeating devices like battery-powered locks and motors, so it's not quite the same.
You can also look for the Z-Wave conformance document on products.z-wavealliance.org to see what the specs for it say. The trick is finding the one that matches your device (and trusting it).
In either case, what you're looking for is "node type." Anything as "always on slave" (this is what you're most likely to see) or "network aware slave" is a repeater. These may be abbreivated AOS or NAS. Anything with "portable" or "sleeping" in the name, which should cover the rest, is not (ignoring controllers, though portable controllers also don't repeat).
Oh, and of course, if you have a C-7 and can see routing tables, anything as an intermediary node in the route column under Z-Wave Details not only is a repeater but is repeating. But of course, that doesn't tell you what's possible, only what's happening.
There might be better ways or something I'm just missing entirely, so I look foward to input others might have here.
(But as you know, the rule is generally that mains-powered devices are and battery powered devices aren't. I'm not aware of any exceptions, aside from if you pair a device that can do either when in the "wrong" state, things like the Zooz outdoor sensor where USB still acts like a battery, and the Ring extender that still repeats on battery but is intended to be on AC.)
Someone correct me if I'm missing something, but I don't think the Z-Wave Mesh Details app (as great as it is--and I do find its visualizations easier to work with than anything I can find on-hub) that has been mentioned a couple times now can tell you if a device is a repeater, only if it is repeating -- basically the issue I alluded to above.
I guess this depends on what the OP really wants, but my assumption was the former. (Or again, maybe I'm missing something.)
I came here to post essentially the same thing. A device capable of being a repeater and a device that is acting as a repeater in the mesh are not the same thing.
That being said, I am working on some enhancements to try to find and expose capabilities like this as well.
As Bill Clinton famously said, it all depends on what the definition of “is” is. I understood the OP to ask whether a device is currently acting as a repeater, but I can see how his question can be taken as asking whether a device is capable of being a repeater.
Thanks to everyone for your high quality answers to my question. My intent was to determine if device is supposed to be a repeater, not if it was actually repeating. Until the responses to my query it never occured to me there could be a repeater that was not repeating, though now that I think about it, a repeating device at the far edge of the network many not be repeating.
In anycase, Tony Fleisher's Hubitat Z-Wave Mesh Details tool answers both questions. Thanks again all, especially Mr Fleisher!