Haven't personally used Discord so not familiar with their setup but wouldn't the Channel's API be relevant for this? Looks like you can pull a channel ID, using this there are messaging APIs available: Create message, trigger typing indicator etc
Unless this is for another feature and not the 'general chat tab'?
From my fast googling, I believe this is only related to Bot API, so only for stuff connected to the server(discord). So technically you could build something that relays chat to discord, but I don't think it'd go the other way. And everything would be under whatever the bot's name would be.