diff --git a/src/libstore/include/nix/store/http-binary-cache-store.hh b/src/libstore/include/nix/store/http-binary-cache-store.hh
index e0f6ce42f..4102c858f 100644
--- a/src/libstore/include/nix/store/http-binary-cache-store.hh
+++ b/src/libstore/include/nix/store/http-binary-cache-store.hh
@@ -1,3 +1,6 @@
+#pragma once
+///@file
+
 #include "nix/util/url.hh"
 #include "nix/store/binary-cache-store.hh"