diff --git a/.github/workflows/build-debug.yml b/.github/workflows/build-debug.yml
index 6f99440..d3cb807 100644
--- a/.github/workflows/build-debug.yml
+++ b/.github/workflows/build-debug.yml
@@ -7,9 +7,8 @@ on:
     tags:
       - "!*" # not a tag push
   pull_request:
-    types:
-      - opened
-      - synchronize
+    branches:
+      - "master"
 
 jobs:
   build-dotnet: