diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index a4ece033..d33ee940 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -1,13 +1,9 @@
 name: CI
 
 on:
-  push:
+  pull_request:
     branches:
       - main
-      - release-*
-    tags:
-      - '*.*.*'
-  pull_request:
 
 jobs:
   check:
@@ -20,7 +16,14 @@ jobs:
     name: check - (${{ matrix.platform }})
     runs-on: ${{ matrix.platform }}
     steps:
-      - uses: actions/checkout@v3
+      - name: 'PR commits + 1'
+        run: echo "PR_FETCH_DEPTH=$(( ${{ github.event.pull_request.commits }} + 1 ))" >> "${GITHUB_ENV}"
+
+      - name: 'Checkout PR branch and PR commits'
+        uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          fetch-depth: ${{ env.PR_FETCH_DEPTH }}
 
       # Ruby rules use host install still: https://github.com/bazelruby/rules_ruby/issues/112
       - name: Setup Ruby