Slack MCP Server

Model Context Protocol (MCP) server for Slack Workspaces. This integration supports both Stdio and SSE transports, proxy settings and does not require any permissions or bots being created or approved by Workspace admins 😏.

Feature Demo

Tools

conversationsHistory

Get messages from the channel by channelID
Required inputs:
- channel_id (string): ID of the channel in format Cxxxxxxxxxx
- limit (number, default: 28): Limit of messages to fetch
Returns: List of messages with timestamps, user IDs, and text content

channelsList

Get list of channels
Required inputs:
- channelTypes (array): Possible channel types. Allowed values: 'mpim', 'im', 'public_channel', 'private_channel'.
- sort (string): Type of sorting. Allowed values: 'popularity' - sort by number of members/participants in each channel.
Returns: List of channels

Setup Guide

1. Authentication Setup

Open up your Slack in your browser and login.

Lookup `SLACK_MCP_XOXC_TOKEN`

Open your browser's Developer Console.
In Firefox, under Tools -> Browser Tools -> Web Developer tools in the menu bar
In Chrome, click the "three dots" button to the right of the URL Bar, then select More Tools -> Developer Tools
Switch to the console tab.
Type "allow pasting" and press ENTER.
Paste the following snippet and press ENTER to execute: JSON.parse(localStorage.localConfig_v2).teams[document.location.pathname.match(/^\/client\/([A-Z0-9]+)/)[1]].token

Token value is printed right after the executed command (it starts with xoxc-), save it somewhere for now.

Lookup `SLACK_MCP_XOXD_TOKEN`

Switch to "Application" tab and select "Cookies" in the left navigation pane.
Find the cookie with the name d. That's right, just the letter d.
Double-click the Value of this cookie.
Press Ctrl+C or Cmd+C to copy it's value to clipboard.
Save it for later.

2. Installation

Choose one of these installation methods:

2.1. Docker

For detailed information about all environment variables, see Environment Variables.

export SLACK_MCP_XOXC_TOKEN=xoxc-...
export SLACK_MCP_XOXD_TOKEN=xoxd-...

docker pull ghcr.io/korotovsky/slack-mcp-server:latest
docker run -i --rm \
  -e SLACK_MCP_XOXC_TOKEN \
  -e SLACK_MCP_XOXD_TOKEN \
  slack-mcp-server --transport stdio

2.2. Docker Compose

wget -O docker-compose.yml https://github.com/korotovsky/slack-mcp-server/releases/latest/download/docker-compose.yml
wget -O .env https://github.com/korotovsky/slack-mcp-server/releases/latest/download/.env.dist
nano .env # Edit .env file with your tokens from step 1 of the setup guide
docker-compose up -d

2.2.1 TLS and Exposing to the Internet

There are several reasons why you might need to setup HTTPS for your SSE.

mcp-remote is capable to handle only https schemes;
it is generally a good practice to use TLS for any service exposed to the internet;

You could use ngrok:

ngrok http 3001

and then use the endpoint https://903d-xxx-xxxx-xxxx-10b4.ngrok-free.app for your mcp-remote argument.

3. Configuration and Usage

You can configure the MCP server using command line arguments and environment variables.

Add the following to your claude_desktop_config.json:

Option 1 with `stdio` transport:

{
  "mcpServers": {
    "slack": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "SLACK_MCP_XOXC_TOKEN=$SLACK_MCP_XOXC_TOKEN",
        "-e",
        "SLACK_MCP_XOXD_TOKEN=$SLACK_MCP_XOXD_TOKEN",
        "ghcr.io/korotovsky/slack-mcp-server",
        "mcp-server",
        "--transport",
        "stdio"
      ],
      "env": {
        "SLACK_MCP_XOXC_TOKEN": "xoxc-...",
        "SLACK_MCP_XOXD_TOKEN": "xoxd-..."
      }
    }
  }
}

Option 2 with `sse` transport:

Complete steps from 2.2 and run docker compose up -d to launch MCP server or with your preferred method and then configure it:

{
  "mcpServers": {
    "slack": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://x.y.z.q:3001/sse",
        "--header",
        "Authorization: Bearer ${SLACK_MCP_SSE_API_KEY}"
      ],
      "env": {
        "SLACK_MCP_SSE_API_KEY": "my-$$e-$ecret"
      }
    }
  }
}

Option 3 with `sse` transport on Windows:

Complete steps from 2.2 and run docker compose up -d to launch MCP server or with your preferred method and then configure it:

{
  "mcpServers": {
    "slack": {
      "command": "C:\\Progra~1\\nodejs\\npx.cmd",
      "args": [
        "-y",
        "mcp-remote",
        "https://x.y.z.q:3001/sse",
        "--header",
        "Authorization: Bearer ${SLACK_MCP_SSE_API_KEY}"
      ],
      "env": {
        "SLACK_MCP_SSE_API_KEY": "my-$$e-$ecret"
      }
    }
  }
}

Console Arguments

Argument	Required ?	Description
`--transport` or `-t`	Yes	Select transport for the MCP Server, possible values are: `stdio`, `sse`

Environment Variables

Variable	Required ?	Default	Description
`SLACK_MCP_XOXC_TOKEN`	Yes	`nil`	Authentication data token field `token` from POST data field-set (`xoxc-...`)
`SLACK_MCP_XOXD_TOKEN`	Yes	`nil`	Authentication data token from cookie `d` (`xoxd-...`)
`SLACK_MCP_SERVER_PORT`	No	`3001`	Port for the MCP server to listen on
`SLACK_MCP_SERVER_HOST`	No	`127.0.0.1`	Host for the MCP server to listen on
`SLACK_MCP_SSE_API_KEY`	No	`nil`	Authorization Bearer token when `transport` is `sse`
`SLACK_MCP_PROXY`	No	`nil`	Proxy URL for the MCP server to use
`SLACK_MCP_SERVER_CA`	No	`nil`	Path to the CA certificate of the trust store
`SLACK_MCP_SERVER_CA_INSECURE`	No	`false`	Trust all insecure requests (NOT RECOMMENDED)

Debugging Tools

# Run the inspector with stdio transport
npx @modelcontextprotocol/inspector go run mcp/mcp-server.go --transport stdio

# View logs
tail -n 20 -f ~/Library/Logs/Claude/mcp*.log

Security

Never share API tokens
Keep .env files secure and private

License

Licensed under MIT - see LICENSE file. This is not an official Slack product.

Integrations