diff --git a/.github/workflows/proto.yml b/.github/workflows/proto.yml
index 1c997e8a65..14db6d8b62 100644
--- a/.github/workflows/proto.yml
+++ b/.github/workflows/proto.yml
@@ -28,4 +28,4 @@ jobs:
       - uses: bufbuild/buf-breaking-action@v1
         with:
           input: "proto"
-          against: "https://github.com/${{ github.repository }}.git#branch=${{ github.event.pull_request.base.ref }},ref=HEAD~1,subdir=proto"
+          against: "https://github.com/${{ github.repository }}.git#branch=${{ github.event.pull_request.base.ref }},subdir=proto"