New elements that are introduced by the nature of living and interacting within an Ambient Intelligence (AmI) environment lead to new HCI paradigms. While AmI User Interfaces are moving off the desktop and the GUI paradigm, and become augmented and diffused within the ubiquitous environments, a new generation of User Interface Design Tools to facilitate the design and realization of AmI applications, is emerging. Issues and specific shifts related to Human Computer Interaction in AmI environments, which affect the design of these tools, is outlined in this paper. The high level characteristics of End User Tools that facilitate users to reason as well as manipulate the behavior of the AmI environment are outlined.