See my reply for info

FB16770732 submitted today thanks

By the way on macOS 15.4.1 (24E263) I found @Query does call body when ModelActor saves 🤔 Seems to me @Query watches for the remote store changed notification, then toggles a bool to and performs another SQL query. CoreData: debug: Remote Change Notification - posting for store ContentView: \QueryController<Item>.<computed (Bool)> changed. CoreData: sql: SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCOUNTER, t0.ZTIMESTAMP, t0.ZUNIQUEIDENTIFIER FROM ZITEM t0 ORDER BY t0.ZTIMESTAMP DESC, t0.Z_PK

I had the same problem and lucky I found this forum post! I've suggested this info be added to the documentation for fetchIdentifiers(_:) FB17555489

That just tests the extension though. It doesn't make Spotlight actually use it. Oh sorry you already added a reply about knowing that.

If it is listed in mdimport -e it can run with mdimport -m -y LOWERCASECONTENTTYPE -u PATHTOAFILE however the attributes aren't actually added to Spotlight's database. And even if the Spotlight extension is enabled in Settings->LoginItems->Spotlight Extensions, Spotlight will never actually run the extension itself. And if in the extension code you attempt to open the file with a try, it throws a permission exception so you wouldn't even be able to compute attributes anyway.

Maybe this old bug returned https://developer.apple.com/forums/thread/79734?page=3