diff --git a/Library/Homebrew/dev-cmd/generate-man-completions.rb b/Library/Homebrew/dev-cmd/generate-man-completions.rb
index d5aebe4b77..eaa6a2ad79 100644
--- a/Library/Homebrew/dev-cmd/generate-man-completions.rb
+++ b/Library/Homebrew/dev-cmd/generate-man-completions.rb
@@ -20,7 +20,7 @@ module Homebrew
   def generate_man_completions_args
     Homebrew::CLI::Parser.new do
       description <<~EOS
-        Generate Homebrew's manpages.
+        Generate Homebrew's manpages and shell completions.
       EOS
       switch "--fail-if-not-changed",
              description: "Return a failing status code if no changes are detected in the manpage outputs. "\