diff --git a/ci_presubmit.sh b/ci_presubmit.sh
new file mode 100755
index 0000000..5abaf10
--- /dev/null
+++ b/ci_presubmit.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+# This is a presubmit (on-merge) CI script.
+# Currently no CI runs it - so be a good cyborg, and run it before submitting
+# changes to hscloud.
+
+set -e -o pipefail
+
+if [ -z "$hscloud_root" ]; then
+    echo 2>&1 "Please first source env.sh"
+    exit 1
+fi
+
+cd $hscloud_root
+
+# Test critical tools.
+tools/install.sh
+kubectl version --client=true
+kubecfg version
+prodaccess --help 2>/dev/null
+bazel run //cluster/clustercfg smoketest