diff --git a/pen-core.el b/pen-core.el
index b86b4d89e..fcd199b6f 100644
--- a/pen-core.el
+++ b/pen-core.el
@@ -6,7 +6,9 @@
 (defun pen-preceding-text ()
   (str (buffer-substring (point) (max 1 (- (point) 1000)))))
 
-(defun pen-surrounding-text ()
+(defun pen-surrounding-text (&optional window-line-size)
+  (if (not window-line-size)
+      (setq window-line-size 20))
   (str (buffer-substring (point) (max 1 (- (point) 1000)))))