CogTool is a general purpose UI prototyping tool with a difference-- it automatically evaluates your design with a predictive human performance model (a "cognitive crash dummy"). Simply create a storyboard of your design idea with sketches, images or on a canvas with CogTool's widgets, demonstrate tasks on that storyboard, then press a button to produce a valid cognitive model predicting how long it will take a skilled user to complete those tasks. CogTool can be used today to baseline your current interface, or compare competitors' interfaces, and predict how much better your new designs will be. CogTool is free software, released under the FSF Lesser Gnu Public License. See LGPL.txt for details. The source code for CogTool is now (as of 9 December 2013) stored on GitHub. To access it clone: https://github.com/cogtool/cogtool.git There is a separate repository of documentation, both for end users and for developers: https://github.com/cogtool/documentation.git For building CogTool from source, see in particular Processes/configuring-development-machines.txt