In my company we use a Git extension which has command-line interface that requires interaction (answering prompt). I would like to extend Magit to be able to deal with our extension. Unlike most of Magit functionality, this has to actually interact with the Git process by collecting users' input (this is company's policy, something to prevent automatic submissions, questionable as it may be, isn't a subject to change).
Ideally, in the future, I'd write a proper extension with a dedicated buffer and, font-faces and key-bindings, but for now, I'd be happy with just the ability to answer yes/no to the prompt.