Slack MCP Server

slack-mcp-server

A MCP(Model Context Protocol) server for accessing Slack API. This server allows AI assistants to interact with the Slack API through a standardized interface.

Features

Available tools:

• slack_list_channels - List public channels in the workspace with pagination
• slack_post_message - Post a new message to a Slack channel
• slack_reply_to_thread - Reply to a specific message thread in Slack
• slack_add_reaction - Add a reaction emoji to a message
• slack_get_channel_history - Get recent messages from a channel
• slack_get_thread_replies - Get all replies in a message thread
• slack_get_users - Retrieve basic profile information of all users in the workspace
• slack_get_user_profile - Get a user's profile information
• slack_search_messages - Search for messages in the workspace

Quick Start

Installation

NOTE: Its now hosted in GitHub Registry so you need your PAT.

Configuration

You need to set the following environment variables:

• SLACK_BOT_TOKEN: Slack Bot User OAuth Token
• SLACK_USER_TOKEN: Slack User OAuth Token (required for some features like message search)

You can also create a .env file to set these environment variables:

Usage

Start the MCP server

Directly:

Or, run the installed module with node:

Edit MCP configuration json for your client:

Implementation Pattern

This server adopts the following implementation pattern:

1. Define request/response using Zod schemas
   • Request schema: Define input parameters
   • Response schema: Define responses limited to necessary fields
2. Implementation flow:
   • Validate request with Zod schema
   • Call Slack WebAPI
   • Parse response with Zod schema to limit to necessary fields
   • Return as JSON

For example, the slack_list_channels implementation parses the request with ListChannelsRequestSchema, calls slackClient.conversations.list, and returns the response parsed with ListChannelsResponseSchema.

Development

Available Scripts

• npm run dev - Start the server in development mode with hot reloading
• npm run build - Build the project for production
• npm run start - Start the production server
• npm run lint - Run linting checks (ESLint and Prettier)
• npm run fix - Automatically fix linting issues

Contributing

1. Fork the repository
2. Create your feature branch
3. Run tests and linting: npm run lint
4. Commit your changes
5. Push to the branch
6. Create a Pull Request