Supports environment variable configuration through .env files for storing Slack tokens and other configuration settings.

Integrated for code linting during development to maintain code quality and consistency.

Hosts the package in GitHub Registry, requiring a Personal Access Token (PAT) for installation and access to the MCP server package.

Used as the package manager for installing and running the MCP server package.

Used for code formatting to ensure consistent code style across the project.

Provides tools for interacting with Slack API, including listing channels, posting messages, replying to threads, adding reactions, retrieving channel history, getting thread replies, retrieving user information, and searching messages in a Slack workspace.

Used for defining and validating request/response schemas, ensuring proper data structure for API interactions and limiting response fields to necessary data.

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

Related MCP server: MCP Toolkit

Quick Start

Installation

npm install @ubie-oss/slack-mcp-server

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:

SLACK_BOT_TOKEN=xoxb-your-bot-token SLACK_USER_TOKEN=xoxp-your-user-token

Usage

Start the MCP server

Directly:

npx @ubie-oss/slack-mcp-server

Or, run the installed module with node:

node node_modules/.bin/slack-mcp-server

Edit MCP configuration json for your client:

{ "slack": { "command": "npx", "args": [ "-y", "@ubie-oss/slack-mcp-server" ], "env": { "NPM_CONFIG_//npm.pkg.github.com/:_authToken": "<your-github-pat>", "SLACK_BOT_TOKEN": "<your-bot-token>", "SLACK_USER_TOKEN": "<your-user-token>" } } }

Implementation Pattern

This server adopts the following implementation pattern:

Define request/response using Zod schemas
- Request schema: Define input parameters
- Response schema: Define responses limited to necessary fields
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

Fork the repository
Create your feature branch
Run tests and linting: npm run lint
Commit your changes
Push to the branch
Create a Pull Request

Slack MCP Server