diff --git a/.github/workflows/pr_detector_labels.yaml b/.github/workflows/pr_detector_labels.yaml
index 18fc718ee..7da9068cf 100644
--- a/.github/workflows/pr_detector_labels.yaml
+++ b/.github/workflows/pr_detector_labels.yaml
@@ -25,7 +25,7 @@ jobs:
         uses: actions/github-script@v8
         with:
           script: |
-            const prNumber = ${{ inputs.pr_number }};
+            const prNumber = ${{ inputs.pr_number || github.event.pull_request.number }};
 
             const { data: pr } =
               await github.rest.pulls.get({