diff --git a/.github/workflows/assign-milestone-on-close.yml b/.github/workflows/assign-milestone-on-close.yml
index beabf5c9846..6cb1dae8c34 100644
--- a/.github/workflows/assign-milestone-on-close.yml
+++ b/.github/workflows/assign-milestone-on-close.yml
@@ -21,7 +21,7 @@ jobs:
         id: payload-content
         uses: actions/github-script@v7
         with:
-          script: return json.stringify(context.payload);
+          script: return JSON.stringify(context.payload);
           result-encoding: string
       - name: Print payload content
         id: print-payload