Maybe I'm missing something really obvious, but I don't understand where Flask fits into the picture. The article seems to introduce the first few steps of how you can debug <i>any</i> Python with pdb, not just Flask applications.
Try "pudb" instead of "pdb" if you want a fullscreen debugger.<p><a href="http://pypi.python.org/pypi/pudb" rel="nofollow">http://pypi.python.org/pypi/pudb</a><p>Also, agreed with tomlu -- this will work for any python app (as long as it doesn't do strange things to stdout -- nose and daemons are probably the most common examples of things that do change stdout).
I tend to use pdb like this a lot. I write about as much of a piece of code as is obvious and then have it drop into pdb. I can then look around and play around with what I could do next.