It is not implemented primarily as an application-managed graphics library (as most systems, following Xerox's design, have done), but rather as a separate task that maintains the state of all the standard UI elements independently from the application.
Like most GUIs of the day, Amiga's Intuition followed Xerox's lead anteceding solutions, but pragmatically, a command line interface was also included and it extended the functionality of the platform.
This was intentional – in a time before cheap high-quality video monitors, Commodore tested output on the worst televisions they could find, with the goal of obtaining the best possible contrast under these worst-case conditions.
Due to the limitations of Intuition's basic widget set, developers adopted other third-party GUI toolkits, such as Magic User Interface (MUI), and ReAction.
There is a brief article on Ambient and descriptions of MUI icons, menus and gadgets here Archived 2005-09-07 at the Wayback Machine (aps.fr) and images of Zune stay at main AROS site.
A new object-oriented toolkit for all Amiga-like platforms (AmigaOS, MorphOS, AROS), Feelin, was introduced in 2005, and makes extensive use of XML guidelines.