Config seem to be smart enough
```
from IPython.core.magic import Magics, magics_class, line_magic, cell_magic
from IPython.config import Configurable
from IPython.utils.traitlets import Unicode

@magics_class
class CWithTraits(Magics):
    
    hello = Unicode('hello', config=True, help='no help')
    
    @cell_magic('foob')
    def foob(self, line, cell):
        print self.hello, "Monde"

@magics_class
class CWithoutTraits(Magics):
    
    @cell_magic('fooq')
    def foob(self, line, cell):
        print "Immutable"

ip = get_ipython()
ip.register_magics(CWithTraits)
ip.register_magics(CWithoutTraits)
```
`%config`
```
Available objects for config:
     ZMQInteractiveShell
     HistoryManager
     PrefilterManager
     IPCompleter
     PromptManager
     DisplayFormatter
     LaTeXTool
     MagicsManager
     ScriptMagics
     AliasManager
     IPKernelApp
     InlineBackend
     StoreMagics
     StoreMagics
     CWithTraits  #<--- Alone
```