The recent release of Cluster Design Tools, version 0.8.4, is different from previous releases. First, it now incorporates SADDLE, a Python-based scripting language for automated design of cluster supercomputers and data centres, which was announced earlier.
Second, it now includes source code for each tool. Source codes are released under the GNU General Public License (GPL) or, for web services, the GNU Affero GPL license. Yes, even the fat-tree design tool is included, and you might be surprised to find it’s written in Object Pascal!
All in all, version 0.8.4 is a solid new release, and you can try it out by downloading and installing it. Just make sure you follow the guidance about the correct version of Python (as of today, version 3.3.0 works fine).
As usual, if something is not working as expected, you know what to do.