diff --git a/lib/telebugs/wrapped_error.rb b/lib/telebugs/wrapped_error.rb
index fa01c46..8f254f1 100644
--- a/lib/telebugs/wrapped_error.rb
+++ b/lib/telebugs/wrapped_error.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telebugs
   # WrappedError unwraps an error and its causes up to a certain depth.
   class WrappedError