diff --git a/action.yml b/action.yml
index 282fca43dea..0d8c172af67 100644
--- a/action.yml
+++ b/action.yml
@@ -36,10 +36,14 @@ runs:
     - name: black
       run: |
         if [ "$RUNNER_OS" == "Windows" ]; then
-          python $GITHUB_ACTION_PATH/action/main.py | tee -a $GITHUB_STEP_SUMMARY
+          out=$(python $GITHUB_ACTION_PATH/action/main.py)
         else
-          python3 $GITHUB_ACTION_PATH/action/main.py | tee -a $GITHUB_STEP_SUMMARY
+          out=$(python3 $GITHUB_ACTION_PATH/action/main.py)
         fi
+
+        echo "\`\`\`python" >> $GITHUB_STEP_SUMMARY
+        echo "${out}" >> $GITHUB_STEP_SUMMARY
+        echo "\`\`\`" >> $GITHUB_STEP_SUMMARY
       env:
         # TODO: Remove once https://github.com/actions/runner/issues/665 is fixed.
         INPUT_OPTIONS: ${{ inputs.options }}