diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 46c3ba8..39ff14e 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -3953,6 +3953,13 @@
 		The optional argument {opts} is a Dict and supports the
 		following items:
 
+			cursor		A String specifying cursor behavior
+					when waiting for a character.
+					"hide": hide the cursor.
+					"keep": keep current cursor unchanged.
+					"msg": move cursor to message area.
+					(default: "msg")
+
 			number		If |TRUE|, return a Number when getting
 					a single character.
 					If |FALSE|, the return value is always