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https://github.com/duolingo/slack-mcp

OAuth-based multi-user Slack MCP server with HTTP transport
https://github.com/duolingo/slack-mcp

http mcp model-context-protocol oauth python slack

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OAuth-based multi-user Slack MCP server with HTTP transport

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# Slack MCP Server

A read-only MCP (Model Context Protocol) server for Slack with OAuth 2.1 authentication.

[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
[![Python 3.10+](https://img.shields.io/badge/python-3.10+-blue.svg)](https://www.python.org/downloads/)

## Demo

https://github.com/user-attachments/assets/211bd428-209f-461a-b9a1-9cc85fd7c438

### Available Tools

- `slack_get_channel_messages` - Retrieve messages from channels
- `slack_get_thread_replies` - Get conversation thread replies
- `slack_search_messages` - Advanced message search with filters
- `slack_get_users` - List workspace users or get specific profiles
- `slack_get_channels` - List channels or get detailed info

## Quick Start

### 1. Create Slack App

1. Visit [Slack API Apps](https://api.slack.com/apps) and create a new app
2. Under **App Credentials**, copy your `Client ID` and `Client Secret`
3. Navigate to **OAuth & Permissions** and add these [**User Token Scopes**](https://docs.slack.dev/reference/scopes/): `channels:history` `groups:history` `im:history` `mpim:history` `channels:read` `groups:read` `im:read` `mpim:read` `users:read` `users:read.email` `search:read`
4. Add **Redirect URL** under **OAuth & Permissions**:
- For local testing: Use an HTTPS proxy like ngrok (E.g: `https://abc123.ngrok.io/oauth2callback`). See local development setup below.
- For production: `https://your-domain.com/oauth2callback`

### 2. Installation

```bash
uv sync
```

### 3. Local Development Setup (HTTPS Proxy)

Slack requires HTTPS for OAuth callbacks. For local development, use ngrok or a similar HTTPS proxy:

```bash
# Visit https://ngrok.com/ to download ngrok and start the proxy
ngrok http 8001
```

Copy the HTTPS forwarding URL (e.g., `https://abc123.ngrok.io/oauth2callback`) and add it as a Redirect URL in your Slack app settings.

### 4. Configuration

Set required environment variables:

```bash
export SLACK_CLIENT_ID="your_client_id"
export SLACK_CLIENT_SECRET="your_client_secret"
# Use https://your-domain.com for production.
export SLACK_MCP_BASE_URI="http://localhost"
# Use https://your-domain.com for production.
export SLACK_EXTERNAL_URL="https://abc123.ngrok.io"
# Optional, if you want to run the MCP server on a different port.
export SLACK_MCP_PORT=8001
```

### 5. Run the Server

```bash
uv run python main.py
```

The server will start on `http://localhost:8001` by default. Make sure your ngrok proxy is running alongside it for OAuth to work.

### 6. Configure Your MCP Client

Add to your MCP client configuration (e.g. ~/.cursor/mcp.json for Cursor):

```json
{
"mcpServers": {
"slack": { "url": "http://localhost:8001/mcp", "transport": "http" }
}
}
```

### 7. Authenticate

Authentication happens automatically via OAuth 2.1 when your MCP client first connects. Your client will open a browser window for Slack authorization — approve access and you're ready to go.

## Deployment

For production deployment, you can run it inside docker:

```bash
docker build -t slack-mcp .
docker run -p 8001:8001 \
-e SLACK_CLIENT_ID="your_client_id" \
-e SLACK_CLIENT_SECRET="your_client_secret" \
-e SLACK_MCP_BASE_URI="https://your-domain.com" \
-e SLACK_EXTERNAL_URL="https://your-domain.com" \
slack-mcp
```

## Development

Run tests with `uv run pytest`.

## License

This project is licensed under the Apache License 2.0 - see the [LICENSE](LICENSE) file for details.

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