A method's description doesn't show up in another class
I recently just went through adding descriptions to DLL's for use in other programs, and I'm pretty sure if you're using the DLL in another solution you need to have the accompanying XML file in the same folder(as the DLL) to get the descriptions working.
Visual Studio built-in “XML Doc” features or free addons
visual-studio-2013,documentation,visual-studio-extensions,xmldoc
You can also use SubMain GhostDoc - I do not believe in 'auto-documenters', and also believe that excessive, unnecessary documentation simply adds noise.. but in my experience GhostDoc has worked well enough to save time for mismanaged projects whose leadership required "everything" to be documented. Great for generating API docs,...
Xml doc - tag on parameter
To reference a parameter you need to use <paramref>: /// <summary> /// Method with parameter <paramref name="foo"/>. /// </summary> ...