Edit and write approvals warn you when a change was too large to preview

When Claude wants to edit or write a file, Claude Code shows a permission dialog, a box asking you to approve the change, with a preview of the differences. If that preview took too long to work out and came back empty, the dialog now shows a warning: "Proposed edit took too long to diff, so it is not shown (deny unless expected)." New file content gets the same warning. Before, an empty preview simply showed nothing.

The edit preview is also built differently. Claude Code reads only the part of the file around the text being replaced, and reads the whole file only if that part turns up nothing.