The CodeContracts tool chain builds its own "contracts" dll (i.e. filename.contracts.dll) that contains all the contracts information that CCDoc or other contract tools need and it must be present in order for them to work. This contracts dll is automatically built if you check the "Build a Contract Reference Assembly" in your CodeContracts settings in VS (similar to the "Emit contracts into XML doc file" option I talked about in the film).
Yes, it's all done with MEF. You can't currently plug into the IntelliSense bubbles, but hopefully in beta 2 or so you will be able to