diff --git a/ci/cmake.yml b/ci/cmake.yml
index 79686c4..eb57306 100644
--- a/ci/cmake.yml
+++ b/ci/cmake.yml
@@ -1,6 +1,10 @@
 name: CMake
 
-on: [push]
+on:
+  push:
+    branches: [ $default-branch ]
+  pull_request:
+    branches: [ $default-branch ]
 
 env:
   # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)