diff --git a/action.yml b/action.yml
index ffca41c..e46e07c 100644
--- a/action.yml
+++ b/action.yml
@@ -20,5 +20,6 @@ runs:
       env:
         GITHUB_ACTION_PATH: ${{ github.action_path }}
 
-    - run: bin/diff-check >> $GITHUB_STEP_SUMMARY
+    - run: >
+        { GITHUB_STEP_SUMMARY=$(bin/diff-check | tee /dev/fd/3); } 3>&1
       shell: bash