diff --git a/.github/workflows/ci-serialisation.yml b/.github/workflows/ci-serialisation.yml
new file mode 100644
index 00000000..efc4fa78
--- /dev/null
+++ b/.github/workflows/ci-serialisation.yml
@@ -0,0 +1,19 @@
+# Sandbox validation of CI_Toolkit item 4 (baseline dependency refs). Not for merge.
+name: CI
+on:
+  pull_request:
+    branches: [develop]
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+jobs:
+  ci-serialisation:
+    runs-on: windows-2025-vs2026
+    timeout-minutes: 90
+    steps:
+      - name: Run serialisation
+        uses: BuroHappoldEngineeringSandbox/CI_Toolkit/.github/actions/ci-serialisation@validate/item4-integration
+        with:
+          app_id: ${{ secrets.BHOM_APP_ID }}
+          private_key: ${{ secrets.BHOM_APP_PRIVATE_KEY }}
+          base_ref: ${{ github.base_ref }}
diff --git a/XML_Adapter/AdapterActions/Pull.cs b/XML_Adapter/AdapterActions/Pull.cs
index 1cbfd1e7..b1630af5 100644
--- a/XML_Adapter/AdapterActions/Pull.cs
+++ b/XML_Adapter/AdapterActions/Pull.cs
@@ -62,3 +62,5 @@ public override IEnumerable<object> Pull(IRequest request, PullType pullType = P
 
 
 
+
+// validate: item 4 integration re-run, no functional change