As an ... I want to ... in order to ...

Problem: Some tools, bots or even users accidentally add duplicate claims to Wikidata entities. We consider that claims are duplicate on an entity if they have identical content (same main snak and set of qualifiers). Duplicate claims should be fixed and prevented, but without disturbing the process of adding new correct, unique claims. Since edits are fine-grained, two claims that aren't intended to be identical may be identical for a few seconds while they are being edited. The Wikidata Query Service doesn't seem to be useful to find duplicate claims because of the long execution times of SPARQL queries.

Example:

Screenshots/mockups:

BDD
GIVEN
AND
WHEN
AND
THEN
AND

Acceptance criteria:

Open questions: