Slack

You deploy this Slack MCP Server to enable your MCP clients to interact with Slack. It exposes a clean set of endpoints that let you list channels, post messages, reply to threads, add reactions, and retrieve channel histories, all while handling Slack authentication securely through a bot token.

How to use

Connect your MCP client to the server’s HTTP endpoint to start using Slack features. The server is designed to be accessed via a dedicated MCP URL and requires a Slack Bot Token for authentication. Once connected, you can list channels, post messages, reply to threads, add reactions, and fetch channel history and thread replies. If you pass Slack URLs, the server can parse them to extract thread and message details and fetch related history and replies.

How to install

Ensure you have Node.js and npm installed on your machine.

# Install dependencies
npm install

# Build the project
npm run build

# Start the server
npm start

Configuration

Configure your MCP client to connect to the Slack MCP Server using the provided MCP URL and your Slack Bot Token. The server expects the URL to be reachable at the given path and uses the token to authenticate all Slack API calls.

{
  "slack-mcp": {
    "url": "http://localhost:3001/sse",
    "env": {
      "SLACK_TOKEN": "xoxb-your-bot-token-here"
    }
  }
}

Security and tokens

Protect your Slack Bot Token. Do not expose the token in client-side code or public repositories. Use environment variables to inject the token at runtime, and store it securely in your deployment environment.

Usage examples and available actions

Use the Slack MCP Server to orchestrate common Slack actions from your MCP clients. The server provides dedicated tools to list channels, post messages to a channel, reply to a thread, add reactions, and retrieve recent history or thread replies.

Notes

All interactions with Slack require a valid Bot Token. The server’s HTTP endpoint is the primary method for MCP clients to connect. If you need to run locally, ensure the server is reachable at the configured URL and that the Slack token environment variable is supplied to the runtime.

Troubleshooting

If you cannot connect to the MCP endpoint, verify that the server is running, check the URL, and confirm that the Slack Bot Token is valid and has the required permissions.

Available tools

slack_list_channels

List public Slack channels with optional pagination, returning channel identifiers and names.

slack_post_message

Post a new message to a specified Slack channel using the channel_id and text parameters.

slack_reply_to_thread

Post a reply to an existing Slack message thread identified by channel_id and thread_ts.

slack_add_reaction

Add an emoji reaction to a specific Slack message identified by channel_id and timestamp.

slack_get_channel_history

Retrieve recent messages from a Slack channel, limited by a specified count.

slack_get_thread_replies

Fetch all replies within a specific message thread using channel_id and thread_ts.

slack_parse_url

Parse a Slack URL to extract channel and thread information, then fetch related history and replies.