As the title says, @Commit (Diff of Working State) can only see changes to existing files. It can’t detect any new files that are being created/added to the repository. I tried several different ways of asking Cursor (agent and chat/ask) to list all files that were created and modified in the @Commit and it could only see the ones that were modified.
@PR (Diff with Main Branch) on the other hand can see everything, including added files.