Is there a way to define the side channel names and their values in the mlagents-learn config file so that Environment will pass those channel values while creating/instantiating the env?
To instantiate the environments according to specific parameters settings, you can specify them in the Environment Parameters section in the config file (see this doc). You’ll be able to access them in Academy.Instance.EnvironmentParameters. In this case you don’t need to create your own side channel.
If the data you’re sending is too complex to fit in the built-in Environment Parameters or you need to use custom data structures, you’ll then need to set up a custom side channel (following [this doc](http://Custom Side Channels)) to define and send your own.