diff --git a/.github/workflows/flake-update.yml b/.github/workflows/flake-update.yml
index fc64204..84bcbf7 100644
--- a/.github/workflows/flake-update.yml
+++ b/.github/workflows/flake-update.yml
@@ -85,6 +85,9 @@ jobs:
               with:
                 files: "pr_body.template"
                 output-filename: "pr_body.md"
+            - name: template diff into PR body
+              run: |
+                nix utils/inject-diff.py
             - name: Save PR body
               id: pr_body
               uses: juliangruber/read-file-action@v1