README - Slack MCP Server with SSE Transport by dvelopment

Slack MCP Server with SSE Transport

A Model Context Protocol (MCP) server that provides Slack API integration using Server-Sent Events (SSE) transport. This server allows AI assistants to interact with Slack workspaces through a simple HTTP-based interface.

Features

SSE Transport: Uses Server-Sent Events (SSE) instead of stdio, enabling communication over HTTP/HTTPS
Slack API Integration: Provides access to essential Slack API functionality
Simple Web Interface: Includes a basic web UI and health check endpoint
Docker Support: Fully containerized with Docker for easy deployment
TypeScript Implementation: Built with TypeScript for type safety and better developer experience
Cross-Platform Compatibility: Works with any MCP client that supports SSE transport

Prerequisites

Node.js 18 or higher
Slack Bot Token with appropriate permissions
Slack Team ID
Docker (optional, for containerized deployment)

Environment Variables

Variable	Description	Default
`SLACK_BOT_TOKEN`	Your Slack Bot User OAuth Token (starts with `xoxb-`)	Required
`SLACK_TEAM_ID`	Your Slack Workspace/Team ID	Required
`PORT`	Port on which the server will run	`3000`

Setup Instructions

Obtaining Slack Bot Token and Team ID

Create a Slack App:
- Visit the Slack Apps page
- Click "Create New App"
- Choose "From scratch"
- Name your app and select your workspace
Configure Bot Token Scopes:
- Navigate to "OAuth & Permissions" in your app settings
- Add these scopes:
  - channels:history - View messages and other content in public channels
  - channels:read - View basic channel information
  - chat:write - Send messages as the app
  - 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 "Bot User OAuth Token" that starts with xoxb-
Get your Team ID:
- Open Slack in a web browser
- Once logged in, check the URL in your browser
- The URL will be in a format like: https://app.slack.com/client/T01234567/...
- Your Team ID is the string beginning with T (e.g., T01234567)

Local Development

Clone the repository
Install dependencies:
```
npm install
```

Create a .env file based on .env.example:

SLACK_BOT_TOKEN=xoxb-your-slack-bot-token
SLACK_TEAM_ID=your-slack-team-id
PORT=3000

Build the TypeScript code:
```
npm run build
```
Start the server:
```
npm start
```

For development with automatic reloading:

npm run dev

Docker Deployment

Using Docker Compose (Recommended)

Create a .env file with your Slack credentials as shown above
Build and run the container:
```
docker compose up --build
```

Using Pre-built Image

docker run -p 3000:3000 \
  -e SLACK_BOT_TOKEN=xoxb-your-slack-bot-token \
  -e SLACK_TEAM_ID=your-slack-team-id \
  ghcr.io/dvelopment/slack-mcp-server-sse:latest

For more detailed Docker instructions, including publishing to GitHub Container Registry, see .

Server Endpoints

SSE Endpoint: /sse - Connect to this endpoint to receive SSE events
Health Check: /health - Simple health check endpoint (returns {"status":"ok"})
Home Page: / - Simple HTML page with information about the server

Available Slack API Tools

Tool Name	Description	Required Parameters
`slack_list_channels`	List public channels in the workspace with pagination	None (optional: `limit`, `cursor`)
`slack_post_message`	Post a new message to a Slack channel	`channel_id`, `text`
`slack_reply_to_thread`	Reply to a specific message thread in Slack	`channel_id`, `thread_ts`, `text`
`slack_add_reaction`	Add a reaction emoji to a message	`channel_id`, `timestamp`, `reaction`
`slack_get_channel_history`	Get recent messages from a channel	`channel_id` (optional: `limit`)
`slack_get_thread_replies`	Get all replies in a message thread	`channel_id`, `thread_ts`
`slack_get_users`	Get a list of all users in the workspace	None (optional: `cursor`, `limit`)
`slack_get_user_profile`	Get detailed profile information for a specific user	`user_id`

Connecting to the Server

Node.js Client Example

// Replace with your server URL
const SERVER_URL = 'http://localhost:3000/sse';

// Create EventSource to connect to the SSE endpoint
const eventSource = new EventSource(SERVER_URL);

// Handle connection open
eventSource.onopen = () => {
  console.log('Connected to SSE server');
};

// Handle messages
eventSource.onmessage = (event) => {
  console.log('Received message:', event.data);
  try {
    const data = JSON.parse(event.data);
    console.log('Parsed data:', data);
  } catch (error) {
    console.log('Raw message (not JSON):', event.data);
  }
};

// Handle errors
eventSource.onerror = (error) => {
  console.error('SSE connection error:', error);
  eventSource.close();
};

See the examples directory for complete client examples:

examples/client.js - Node.js client example
examples/browser-client.html - Browser client example

Using with Claude MCP Wrapper

To use this server with the Claude MCP wrapper:

claude_mcp_wrapper.sh -y docker run -i --rm -e SLACK_BOT_TOKEN -e SLACK_TEAM_ID mcp/slack

Or for an SSE-based connection:

claude_mcp_wrapper.sh -y http://localhost:3000/sse

License

MIT