@cordoval the problem is that adding the DescriptorHelper to the helperset does not make you able to change the behaviour of the help command. That command always uses [his own instance](https://github.com/symfony/Console/blob/master/Command/HelpCommand.php#L83) of the DescriptorHelper.

So then the question is what you want to do with this descriptor if you can't use it to customize the help command.

Then if you look at the FrameworkBundle, you can see a [descriptor for routes and services](https://github.com/symfony/FrameworkBundle/blob/master/Console/Descriptor/Descriptor.php). That's a very good use-case and also the only use-case I can think of. The DescriptorHelper can be usefull to use when you want to print objects in various formats.

And then we come to @weaverryan's point, the current example is not correct. In that case, you don't want to override the `Descriptor`, but the `DescriptorInterface`. You also don't want to add a new format to the help descriptor, that's not possible, you want to create your own type of descriptors for your own classes.

For instance, I can see a use-case for this in the FosUserBundle which prints out information about the current users. Or in the DoctrinePhpcrBundle, which prints out information about a PHPCR node.

That's the things that should be covered in this article imo.

 > So, (2) is the only use-case I see. Are there others? And for (2), I don't really see any value in extending the default Descriptor class: https://github.com/symfony/symfony/blob/2.3/src/Symfony/Component/Console/Descriptor/Descriptor.php. That's because that concrete implementation is all about printing InputOptions, Applications, etc - which I don't think is helpful. You'll instead implement the interface (https://github.com/symfony/symfony/blob/2.3/src/Symfony/Component/Console/Descriptor/DescriptorInterface.php), which means creating a describe class where you have a switch-case statement for the different type of objects that you'll want to print. And then you'll create maybe 2 concrete classes that implement the interface to dump in, say, Json and YAML.