Ben,
I have tackled this kind of requirement in the past using DeepLink and URL Redirector. To provide Oauth authentication into third party tools (Microsoft Dynamics in one case), I:
I realize this may not be the requirement you have, but thought this may give you some ideas about how to proceed.
Hope that helps,
Mike
**EDIT**
I think some additional pictures might help.
Here is my DeepLink configuration:
and here is the microflow that this deeplink is mapped to:
I was able configure the deep link as well as URL Redirector as per the documentation. Here is the flow
But, I am not sure how to access the response body within the microflow that deep link maps to. Any help would be appreciated.