Riak CS does not ship with a default configuration because it needs at least access_id and access_secret to work. Add the riakcs entry in your dragent.yaml with those unique parameters:

  - name: riakcs
    pattern:
      comm: beam.smp
      port: 8080
    conf:
      access_id: "my_access_id"
      access_secret: "my_access_secret"
      #is_secure: false 
      s3_root: s3.amazonaws.dev

To get statistics, app_checks also needs permissions to read the riak-cs bucket.