The Discord client is difficult to use, so I am thinking of creating a simple client for myself.
I was able to register the app with Discord and do OAuth2 authentication to get a list of the guilds I am a member of.

curl -H "Authorization: Bearer xxxxxxxx" https://discordapp.com/api/users/@me/guilds

However, I am unable to get a list of channels within each guild.
Is this possible in terms of authorization?
Or do I need to ask the administrator of each guild to add a bot user?

$ curl -H "Authorization: Bearer xxxxx" https://discordapp.com/api/guilds/10234567890
{"message": "401: Unauthorized", "code": 0}