I'm pretty sure that nothing like this exists, though I agree that it would be great to have - not as a substitute for Wikibase's editing UI, but as an alternate interface, either on wikidata.org or on some other site that interfaces with Wikidata. (One small correction: you wrote "Page Forms (i.e. Semantic MediaWiki)", but actually there's no direct connection between the two extensions - Page Forms can also work with the Cargo extension, or by itself.) I think that all that's needed, conceptually speaking, to enable this sort of thing is direct storage of the expected "domain" of each property, and to a lesser extent, its "range" - for instance, that the "capital" property applies to countries and states but not TV shows, and that its values are cities but not trains. This sort of information is already stored pretty comprehensively in talk pages; see here, for example: https://www.wikidata.org/wiki/Property_talk:P36 ...but I think it would be better to store it as true data, directly on each page. If that were done, it would be easy, or at least doable, to create a form on the fly for any Wikidata entity: the form would find all properties that have this entity in their domain, then display an input for each one. Property ranges, also known as "allowed values", could then potentially be used to assist with autocompletion. Storing domains and ranges could also enable much easier *querying* interfaces - using a very similar approach, an interface could display just the properties that users are most likely to want to query on for any "class" of entities. I've raised this idea before with Wikidata developers, by the way, and the response I tend to get is that the real world is very complex, so making official rules of that sort will lead to problems because any rule will have exceptions. Examples are sometimes brought up like a city that elected a dog as its mayor or some such. My response is that (a) the exceptions, as far as I can tell, tend to happen much more in the ranges of properties than their domains - and ranges are less important, and (b) as long as rules like these are treated as guidelines only, and users still have a way to add any data they want to, there's no problem. -Yaron On Mon, Mar 13, 2017 at 8:49 PM, Greg S <stuppie(a)gmail.com> wrote: -- WikiWorks · MediaWiki Consulting · http://wikiworks.com