Slack Scopes Overview

Scopes give the app permission to carry out actions, e.g. post messages, in the development workspace.

Open the development workspace, either in a web page or in the Slack desktop app.

Sidebar > OAuth & Permissions > Scopes > Add an OAuth Scope

• chat:write scope to the Bot Token to allow the app to post messages
• channels:read scope too so your app can gain knowledge about public Slack channels
• commands scope to build a Slash command.
• incoming-webhook scope to use Incoming Webhooks.
• chat:write.public scope to gain the ability to post in all public channels, without joining. Otherwise, you'll need to use conversations.join, or have your app invited by a user into a channel, before you can post.
• chat:write.customize scope to adjust the app's message authorship to make use of the username, icon_url, and icon_emoji parameters in chat.postMessage.

Add scopes to the Bot Token.

Only add scopes to the User Token when the app needs to act as a specific user (e.g. post message as user, set user status, etc.)

If the scopes applied to a Slack App are changed, the Slack App must be redeployed to the workspace (and Slack App Directory) for the changes to take effect.