Using Reflection and Attributes with CallerMemberName to redirect WebApi calls

For a current client I am building an MVC4.5 HTML5 web front end that performs WebApi calls to a service that is under development.
This is great, except some calls I need to make don’t exist yet, even though I know what they will look like.
So in order to work speculatively I have had to create a dummy WebApi service in a separate project that lives at another url, and this is where I create the non-existing calls. These return dummy info that has the correct shape.

I don’t want to go through the whole code again and change the urls where the dummy calls are. So I am using Attributes and Reflection to detect calls that need to go to the dummy url at present. Then later I can just delete the Attribute, clean up the build errors, and I have a complete service pointing to the correct places!

The Attribute class that decorates calls to point to the dummy service:

BaseHttpClient that detects the Development Attribute using the CallerMemberName feature release in .Net4.5

and the Attribute in use on the class that calls the WebApi

So when all the calls have been finally implemented on the clients api, I can redirect all the dummy redirection.