jsondiffs are too broad

These diffs feel a bit too broad to me. All I did was add two identifiers and it replaced the entire item.

Start by reproducing the JSON diff shown in the issue after adding two identifiers and compare the generated diff with the intended item-level change. Identify the diff entry point and existing tests, then define the narrower expected output before changing behavior; done means identifier-only edits no longer replace the entire item.

Written by the indexing model from the issue text.