diff --git a/lib/rob b/lib/rob
index 4756d493b..27bf79868 100644
--- a/lib/rob
+++ b/lib/rob
@@ -405,3 +405,4 @@ Thanks for reporting it.
 I told this anecdote in an internal talk at Google. You might have seen it then.
 Let me ask, because I'm genuinely curious: Why does it matter?
 I find this situation unsatisfactory.
+Critical code needs static typing.