diff --git a/.github/workflows/check_code_format.yml b/.github/workflows/check_code_format.yml
index fce3fd6..593ce28 100644
--- a/.github/workflows/check_code_format.yml
+++ b/.github/workflows/check_code_format.yml
@@ -31,6 +31,8 @@ jobs:
           if [[ $(git status --porcelain) ]]; then
              echo "please reformat/fprettify these files:"
              git status --porcelain=v1
+             echo "exact diff:"
+             fprettify --indent 4 --recursive --diff . 2>&1
              exit 1
           fi
 ...