diff --git a/.github/workflows/sync-fork.yml b/.github/workflows/sync-fork.yml
new file mode 100644
index 0000000..32b4c25
--- /dev/null
+++ b/.github/workflows/sync-fork.yml
@@ -0,0 +1,27 @@
+name: Sync fork
+
+on:
+  workflow_dispatch:
+  schedule:
+    # 10:00 Asia/Shanghai every day (GitHub Actions cron uses UTC).
+    - cron: "0 2 * * *"
+
+permissions:
+  contents: write
+
+concurrency:
+  group: sync-fork-main
+  cancel-in-progress: false
+
+jobs:
+  sync-main:
+    if: github.repository == 'codychen123/PolyHermes'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Sync fork main from upstream
+        run: |
+          gh repo sync "$GITHUB_REPOSITORY" \
+            --source WrBug/PolyHermes \
+            --branch main
+        env:
+          GH_TOKEN: ${{ github.token }}