diff --git a/.github/workflows/mirroring.yml b/.github/workflows/mirroring.yml
index d96d2aa6..2c5fd0d0 100644
--- a/.github/workflows/mirroring.yml
+++ b/.github/workflows/mirroring.yml
@@ -1,15 +1,19 @@
 name: Mirroring
 
-on: [push, delete]
+on:
+  push:
+    branches:
+      - master
+  delete:
+    branches:
+      - master
 
 jobs:
   mirroring:
     runs-on: ubuntu-18.04
     steps:
-    - uses: actions/checkout@v1
-    - uses: pixta-dev/repository-mirroring-action@v1
-      with:
-        target_repo_url:
-          git@gitlab.com:hodgef/simple-keyboard.git
-        ssh_private_key:
-          ${{ secrets.GL_KEY }}
+      - uses: actions/checkout@v1
+      - uses: pixta-dev/repository-mirroring-action@v1
+        with:
+          target_repo_url: git@gitlab.com:hodgef/simple-keyboard.git
+          ssh_private_key: ${{ secrets.GL_KEY }}