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

1. conversations_history
- Get messages from the channel by channelID
- Required inputs:
- channel_id (string): ID of the channel in format Cxxxxxxxxxx.
- cursor (string): Cursor for pagination. Use the value of the last row and column in the response as next_cursor field returned from the previous request.
- limit (number, default: 28): Limit of messages to fetch.
- Returns: List of messages with timestamps, user IDs, and text content

2. channels_list
- Get list of channels
- Required inputs:
- channel_types (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:

- npx
- Docker

3. Configuration and Usage

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

Using npx

If you have npm installed, this is the fastest way to get started with slack-mcp-server on Claude Desktop.

Open your claude_desktop_config.json and add the mcp server to the list of mcpServers:
`` json
{
"mcpServers": {
"slack": {
"command": "npx",
"args": [
"-y",
"slack-mcp-server@latest",
"--transport",
"stdio"
],
"env": {
"SLACK_MCP_XOXC_TOKEN": "xoxc-...",
"SLACK_MCP_XOXD_TOKEN": "xoxd-..."
}
}
}
}


<details>

<summary>Or, stdio transport with docker.</summary>

Please see Docker for more information.

</details>

Using npx with sse transport:

In case you would like to run it in sse mode, then you  should use mcp-remote wrapper for Claude Desktop and deploy/expose MCP server somewhere e.g. with ngrok or docker-compose.

<details>

<summary>Or, sse transport for Windows.</summary>

</details>

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:

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

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

Or, the docker-compose way:

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