diff --git a/.github/workflows/ws_tool.yaml b/.github/workflows/ws_tool.yaml
index 94368ee5..d1713202 100644
--- a/.github/workflows/ws_tool.yaml
+++ b/.github/workflows/ws_tool.yaml
@@ -26,4 +26,5 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: recursive
+          ref: ${{ github.event.pull_request.head.ref }}
       - run: ws_tool/test/bats/bin/bats ws_tool/test