I really like the exception chaining feature of Python 3. I also like the fact that an exception instance now has access to the traceback, making it the only object you need to start a debugging session from an exception. However, the stock pdb module still does not make it easy to inspect the chained exceptions. So I've recently added that feature to my debugger module. It's contained in the Elicit package. https://pypi.org/project/elicit/ The new commands "switch", and "cause" will switch tracebacks to the "context", or "cause" exceptions, respectively. The elicit framework is a CLI framework that the debugger uses (replaces cmd). It has no other dependencies itself. To get this feature you should enter the debugger from the function "from_exception(exc)". The "post_mortem" function only takes a traceback, so you lose the active exception in some cases.