diff --git a/.github/workflows/check_mandatory_trailers.yml b/.github/workflows/check_mandatory_trailers.yml
index 8370f3419..ad4d0c673 100644
--- a/.github/workflows/check_mandatory_trailers.yml
+++ b/.github/workflows/check_mandatory_trailers.yml
@@ -1,6 +1,7 @@
 name: Check Mandatory Trailers
 
-on: [push]
+on:
+  - pull_request
 
 jobs:
   check-mandatory-trailers: