Slack MCP Server

Integrate the Slack Web API into agentic workflows via MCP.

Tools

1. search_messages
2. get_message_thread

Setup

Access Token

Create a Slack app and obtain a User OAuth Token (starts with xoxp-). Ensure the authorized user is a member of the channels you want to search.

Required environment variables (can be set in your shell or a .env file):

• SLACK_AUTH_USER_TOKEN (starts with xoxp-)
• SLACK_SEARCH_CHANNELS (comma-separated channel names without '#' with no leading or trailing spaces)

Example .env:

SLACK_AUTH_USER_TOKEN=xoxp-...
SLACK_SEARCH_CHANNELS=general,random

Slack Scopes

Grant the following user token scopes to your Slack app (choose public and/or private based on your needs):

• search:read
• channels:history (public) and/or groups:history (private) (read messages and other content in a user’s public channels)
• channels:read / groups:read (view basic information about public channels in a workspace)
• channels:history (read messages and other content in a user’s public channels)
• links:read (view URLs in messages)
• search:read (search a workspace’s content)
• search:read.private (search a workspace's content in private channels)
• search:read.public (search a workspace's content in public channels)
• search:read.users (search a workspace's users)
• users.profile:read (view a user’s profile information)

Usage with Claude Desktop

To use this with Claude Desktop, add the following to your claude_desktop_config.json:

{
  "mcpServers": {
    "slack": {
      "command": "npx",
      "args": [
        "-y",
        "@tomgutt/slack-mcp"
      ],
      "env": {
        "SLACK_AUTH_USER_TOKEN": "xoxp-...",
        "SLACK_SEARCH_CHANNELS": "general,random"
      }
    }
  }
}

NPX

If published, you can run it directly via NPX (example shown in the Claude configuration above).

Run locally

Build:

npm run build

Use the mcp inspector:

npm run inspector

Test a tool without inspector

./run-test.sh

Tool Inputs

• search_messages: { query: string, messageCount?: number, includeThreads?: boolean, threadCount?: number, sortMessages?: "mostRelevant" | "latest" | "oldest" }
• get_message_thread: { channelId: string, ts: string, threadCount?: number }

All tools restrict results to SLACK_SEARCH_CHANNELS. sortMessages is only used for search_messages.

Changes to original

• Implements Slack message search with optional thread inclusion and paging
• Adds lightweight response shaping to reduce token usage
• Provides a channel allow-list via SLACK_SEARCH_CHANNELS

License

This MCP server is licensed under the MIT License. See LICENSE for details.