diff --git a/deploy/prod.tag b/deploy/prod.tag
new file mode 100644
index 0000000..e0594d0
--- /dev/null
+++ b/deploy/prod.tag
@@ -0,0 +1,5 @@
+# Desired deployment state for the homelab, consumed by
+# ~/containers/car-tracker/reconcile.sh. The value must be a full 40-character
+# commit SHA of a revision whose image has been pushed to the Gitea registry as
+# tonio/car-tracker:<sha>. To roll back, revert the commit that changed this file.
+2c58234fd9f360f262fde255fae5273ec8f57f6c