Slack User MCP Server

MCP Server for the Slack API, enabling Claude to interact with Slack workspaces as a user.

Tools

slack_list_channels
- List public channels in the workspace
- Optional inputs:
  - limit (number, default: 100, max: 200): Maximum number of channels to return
  - cursor (string): Pagination cursor for next page
- Returns: List of channels with their IDs and information
slack_post_message
- Post a new message to a Slack channel
- Required inputs:
  - channel_id (string): The ID of the channel to post to
  - text (string): The message text to post
- Returns: Message posting confirmation and timestamp
slack_reply_to_thread
- Reply to a specific message thread
- Required inputs:
  - channel_id (string): The channel containing the thread
  - thread_ts (string): Timestamp of the parent message
  - text (string): The reply text
- Returns: Reply confirmation and timestamp
slack_add_reaction
- Add an emoji reaction to a message
- Required inputs:
  - channel_id (string): The channel containing the message
  - timestamp (string): Message timestamp to react to
  - reaction (string): Emoji name without colons
- Returns: Reaction confirmation
slack_get_channel_history
- Get recent messages from a channel
- Required inputs:
  - channel_id (string): The channel ID
- Optional inputs:
  - limit (number, default: 10): Number of messages to retrieve
- Returns: List of messages with their content and metadata
slack_get_thread_replies
- Get all replies in a message thread
- Required inputs:
  - channel_id (string): The channel containing the thread
  - thread_ts (string): Timestamp of the parent message
- Returns: List of replies with their content and metadata
slack_get_users
- Get list of workspace users with basic profile information
- Optional inputs:
  - cursor (string): Pagination cursor for next page
  - limit (number, default: 100, max: 200): Maximum users to return
- Returns: List of users with their basic profiles
slack_get_user_profile
- Get detailed profile information for a specific user
- Required inputs:
  - user_id (string): The user's ID
- Returns: Detailed user profile information

Setup

Create a Slack App:
- Visit the Slack Apps page
- Click "Create New App"
- Choose "From scratch"
- Name your app and select your workspace
Configure User Token Scopes: Navigate to "OAuth & Permissions" and add these scopes:
- channels:history - View messages and other content in public channels
- channels:read - View basic channel information
- chat:write - Send messages as yourself
- reactions:write - Add emoji reactions to messages
- users:read - View users and their basic information
Install App to Workspace:
- Click "Install to Workspace" and authorize the app
- Save the "User OAuth Token" that starts with xoxp-
Get your Team ID (starts with a T) by following this guidance

Usage with Claude Desktop

Add the following to your claude_desktop_config.json:

Local Installation

First install and build the server:

git clone https://github.com/lars-hagen/slack-user-mcp.git
cd slack-user-mcp
npm install
npm run build

Then configure Claude Desktop:

{
  "mcpServers": {
    "slack": {
      "command": "npm",
      "args": [
        "run",
        "--prefix",
        "/path/to/slack-user-mcp",
        "start"
      ],
      "env": {
        "SLACK_TOKEN": "xoxp-your-user-token",
        "SLACK_TEAM_ID": "T01234567"
      }
    }
  }
}

NPX

{
  "mcpServers": {
    "slack": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-slack-user"
      ],
      "env": {
        "SLACK_TOKEN": "xoxp-your-user-token",
        "SLACK_TEAM_ID": "T01234567"
      }
    }
  }
}

Docker

{
  "mcpServers": {
    "slack": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "SLACK_TOKEN",
        "-e",
        "SLACK_TEAM_ID",
        "mcp/slack-user"
      ],
      "env": {
        "SLACK_TOKEN": "xoxp-your-user-token",
        "SLACK_TEAM_ID": "T01234567"
      }
    }
  }
}

Installing via Smithery

To install Slack User Server for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @lars-hagen/slack-user-mcp2 --client claude

Troubleshooting

If you encounter permission errors, verify that:

All required scopes are added to your Slack app
The app is properly installed to your workspace
The tokens and workspace ID are correctly copied to your configuration
The app has been added to the channels it needs to access
You're using a User OAuth Token (starts with xoxp-) not a Bot Token

Build

Docker build:

docker build -t mcp/slack-user -f src/slack/Dockerfile .

License

This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.