Adding ROLE_ASSISTANT capability to your app

I just read that we can now add the assistant feature to our own app. I've added this intent in my manifest:

<action android:name="android.intent.action.ASSIST" />

And then trying to capture the audio input (using the MediaRecorder APIs) when I speak into my Bluetooth voice remote, but just getting silence. It seems like I need to add this role, RoleManager.ROLE_ASSISTANT to my app. Any ideas how this can be done? Thanks in advance