Are you sure cooking with a tagine pot doesn't need any liquid? I mean, maybe I just haven't seen enough recipes for using a tagine, but the one I did see does require at least some broth or water to be used. They just need less than regular pot simmering recipes.
Like, did the author maybe confuse tagine with the Yunnan qiguo pot? That's the kind of pot that I've heard can "magically produce water", but it's more because the pot draws freshwater from seawater that is put under the pot.