diff --git a/puppet-strings.gemspec b/puppet-strings.gemspec
index 2e8de0c..eb8be88 100644
--- a/puppet-strings.gemspec
+++ b/puppet-strings.gemspec
@@ -19,5 +19,6 @@ Gem::Specification.new do |s|
   s.files = `git ls-files`.split("\n") - Dir['.*', '*.gemspec']
 
   s.add_runtime_dependency 'yard', '~> 0.9.5'
+  s.add_runtime_dependency 'rgen'
   s.requirements << 'puppet, >= 3.7.0'
 end