01-authentication-setup.md

1. Authentication Setup

Open up your Slack in your browser and login.

Note: You only need one of the following: an xoxp-* User OAuth token, an xoxb-* Bot token, or both xoxc-* and xoxd-* session tokens. User/Bot tokens are more secure and do not require a browser session. If multiple are provided, priority is xoxp > xoxb > xoxc/xoxd.

Option 1: Using SLACK_MCP_XOXC_TOKEN/SLACK_MCP_XOXD_TOKEN (Browser session)

Lookup SLACK_MCP_XOXC_TOKEN

• Open your browser's Developer Console.
• In Firefox, under Tools -> Browser Tools -> Web Developer tools in the menu bar
• In Chrome, click the "three dots" button to the right of the URL Bar, then select More Tools -> Developer Tools
• Switch to the console tab.
• Type "allow pasting" and press ENTER.
• Paste the following snippet and press ENTER to execute: JSON.parse(localStorage.localConfig_v2).teams[document.location.pathname.match(/^\/client\/([A-Z0-9]+)/)[1]].token

Token value is printed right after the executed command (it starts with xoxc-), save it somewhere for now.

Lookup SLACK_MCP_XOXD_TOKEN

• Switch to "Application" tab and select "Cookies" in the left navigation pane.
• Find the cookie with the name d. That's right, just the letter d.
• Double-click the Value of this cookie.
• Press Ctrl+C or Cmd+C to copy it's value to clipboard.
• Save it for later.

Option 2: Using SLACK_MCP_XOXP_TOKEN (User OAuth)

Instead of using browser-based tokens (xoxc/xoxd), you can use a User OAuth token:

1. Go to api.slack.com/apps and create a new app

2. Under "OAuth & Permissions", add the following to the "User Token Scopes":

   • channels:history - View messages in public channels
   • channels:read - View basic information about public channels
   • groups:history - View messages in private channels
   • groups:read - View basic information about private channels
   • im:history - View messages in direct messages.
   • im:read - View basic information about direct messages
   • im:write - Start direct messages with people on a user’s behalf (new since v1.1.18)
   • mpim:history - View messages in group direct messages
   • mpim:read - View basic information about group direct messages
   • mpim:write - Start group direct messages with people on a user’s behalf (new since v1.1.18)
   • users:read - View people in a workspace.
   • chat:write - Send messages on a user's behalf. (new since v1.1.18)
   • search:read - Search a workspace's content. (new since v1.1.18)
   • usergroups:read - View user groups in a workspace.
   • usergroups:write - Create and manage user groups.
   • channels:write - Join and leave public channels.

3. Install the app to your workspace

4. Copy the "User OAuth Token" (starts with xoxp-)

App manifest (preconfigured scopes)

To create the app from a manifest with permissions preconfigured, use the following code snippet:

{
    "display_information": {
        "name": "Slack MCP"
    },
    "oauth_config": {
        "scopes": {
            "user": [
                "channels:history",
                "channels:read",
                "groups:history",
                "groups:read",
                "im:history",
                "im:read",
                "im:write",
                "mpim:history",
                "mpim:read",
                "mpim:write",
                "users:read",
                "chat:write",
                "search:read",
                "usergroups:read",
                "usergroups:write",
                "channels:write"
            ]
        }
    },
    "settings": {
        "org_deploy_enabled": false,
        "socket_mode_enabled": false,
        "token_rotation_enabled": false
    }
}

Option 3: Using SLACK_MCP_XOXB_TOKEN (Bot Token)

You can also use a Bot token instead of a User token:

1. Go to api.slack.com/apps and create a new app
2. Under "OAuth & Permissions", add Bot Token Scopes (same as User scopes above, except replace search:read with search:read.public and replace channels:write with channels:join + channels:manage)
3. Install the app to your workspace
4. Copy the "Bot User OAuth Token" (starts with xoxb-)
5. Important: Bot must be invited to channels for access

Note: Bot tokens cannot use search.messages API, so conversations_search_messages tool will not be available.

See next: Installation