I still can't find a way to query only some item properties (e.g. claims) from the Wikibase API using pywikibot.
I've tried all of them:

.get('claims')
.get(True, 'claims')
.get(force=True, 'claims')
.get('claims', force=True)
.get('claims', True)

but without success.
Bots often don't need all of the items' data, so such feature should be implemented (or, if present, documented better!)
PS: is it worth to implement the 'wbgetclaims' action in our framework?