Your Hook Says "Blocking Error" But the File Still Changed? PostToolUse and PreToolUse Don't Actually Block the Same Way

You wrote a hook on the PostToolUse event that returns exit 2 whenever it detects a file that shouldn't have been touched. The terminal prints a red line: "blocking error." You breathe a sigh of relief, assuming the edit just got blocked — then you open the file and the content is already changed. This isn't a misconfiguration on your part. It's that the PostToolUse event type was never...