diff --git a/module.nix b/module.nix
index 1c418a1..241c118 100644
--- a/module.nix
+++ b/module.nix
@@ -41,7 +41,7 @@ in
       };
       challengePath = mkOption {
         type = types.str;
-        description = "The location for ACME challenges";
+        description = "The location for ACME challenges.";
       };
     };