diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 9af4f2a..434cfce 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -1,6 +1,10 @@
 name: CI
 
-on: [push, workflow_dispatch]
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches: [ main ]
 
 jobs:
   build: