diff --git a/collects/setup/option-sig.rkt b/collects/setup/option-sig.rkt
index f545cca0b4..d97ad6a660 100644
--- a/collects/setup/option-sig.rkt
+++ b/collects/setup/option-sig.rkt
@@ -20,6 +20,7 @@
      make-planet
      avoid-main-installation
      make-tidy
+     make-doc-index
      call-install
      call-post-install
      pause-on-errors