diff --git a/sdbusplus/message/types.hpp b/sdbusplus/message/types.hpp
index fd4a294..5200772 100644
--- a/sdbusplus/message/types.hpp
+++ b/sdbusplus/message/types.hpp
@@ -123,7 +123,7 @@
  *  @tparam T - C++ type.
  *
  *  Struct must have a 'value' tuple containing the dbus type.  The default
- *  value is an empty tuple, which can be used to indicate
+ *  value is an empty tuple, which is used to indicate an unsupported type.
  */
 template <typename T> struct type_id : public undefined_type_id {};
     // Specializations for built-in types.