diff --git a/.repo/nvchecker.toml b/.repo/nvchecker.toml
index a7b40d6..35393ab 100644
--- a/.repo/nvchecker.toml
+++ b/.repo/nvchecker.toml
@@ -728,6 +728,10 @@ use_max_tag = true
 source = "gems"
 gems = "nanoc"
 
+[ruby-nanoc-external]
+source = "gems"
+gems = "nanoc-external"
+
 [ruby-tty-which]
 source = "gems"
 gems = "tty-which"