@mkusaka/mcp-server-slack-notify

MCP server for sending notifications to Slack using OAuth bot tokens.

Features

• Send formatted messages to Slack channels with title and description
• Mention specific users automatically with the mention parameter
• Support for Slack's markdown formatting
• Clean message formatting with optional header
• TypeScript support with full type safety

Installation

npm install @mkusaka/mcp-server-slack-notify
# or
pnpm add @mkusaka/mcp-server-slack-notify

Configuration

Creating a Slack App

1. Create a new Slack app

2. Configure OAuth scopes

3. Install the app to your workspace

4. Get your Bot Token

5. Invite the bot to channels

Environment Variables

Set the following environment variables:

• `SLACK_BOT_TOKEN` (required): Your Bot User OAuth Token from step 4
• `SLACK_DEFAULT_CHANNEL` (optional): Default channel for notifications (e.g., `#general`)
• `SLACK_MENTIONS` (optional): Default user IDs to mention in all messages (e.g., `U1234567890,U0987654321`)

Usage with Claude Desktop

Add to your Claude Desktop configuration:

{
  "mcpServers": {
    "slack-notify": {
      "command": "npx",
      "args": ["-y", "@mkusaka/mcp-server-slack-notify@latest"],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-your-token-here",
        "SLACK_DEFAULT_CHANNEL": "#general",
        "SLACK_MENTIONS": "U1234567890,U0987654321"
      }
    }
  }
}

Usage with Claude Code

You can add this MCP server to Claude Code using the following command:

claude mcp add slack-notify -e SLACK_BOT_TOKEN=xoxb-your-token-here -e SLACK_DEFAULT_CHANNEL=#general -e SLACK_MENTIONS=U1234567890,U0987654321 -- npx -y @mkusaka/mcp-server-slack-notify@latest

Or if you have the package installed globally:

# Install globally first
npm install -g @mkusaka/mcp-server-slack-notify

# Then add to Claude Code
claude mcp add slack-notify -e SLACK_BOT_TOKEN=xoxb-your-token-here -e SLACK_DEFAULT_CHANNEL=#general -e SLACK_MENTIONS=U1234567890,U0987654321 -- mcp-server-slack-notify

To add with user scope (available across all projects):

claude mcp add --scope user slack-notify -e SLACK_BOT_TOKEN=xoxb-your-token-here -e SLACK_DEFAULT_CHANNEL=#general -e SLACK_MENTIONS=U1234567890,U0987654321 -- npx -y @mkusaka/mcp-server-slack-notify@latest

Available Tools

send_slack_notification

Sends a notification to a Slack channel.

Parameters:

• `channel` (optional): The Slack channel (e.g., #general or C1234567890)
• `title` (optional): The notification title (if provided, displays with header formatting)
• `description` (required): The notification body (supports Slack markdown)
• `mention` (optional): User ID(s) to mention. Can be a single user ID (e.g., U1234567890) or multiple IDs separated by commas (e.g., U1234567890,U0987654321)

Formatting Guide

The description field supports Slack's mrkdwn formatting:

• Mentions:
  • User: `` (use the user's ID)
  • Channel: `` (use the channel's ID)
  • @here: ``
  • @channel: ``
  • User groups: `` (use the subteam's ID)
  • Note: When using the `mention` parameter or `SLACK_MENTIONS` environment variable, user mentions are automatically added at the beginning of the message
• Text formatting:
  • Bold: `*bold text*`
  • Italic: `_italic text_`
  • Strikethrough: `~strikethrough text~`
  • Code: `` `inline code` ``
  • Code block: ` ```code block``` `
  • Quote: `> quoted text`
  • Link: ``

Development

# Install dependencies
pnpm install

# Run tests
pnpm test

# Build
pnpm build

# Run in development mode
pnpm start

# Debug with MCP Inspector
pnpm debug

Testing

The project includes comprehensive tests using Vitest with mocked Slack API calls.

# Run tests
pnpm test

# Run tests in watch mode
pnpm test:watch

License

MIT