# Slack Notifier MCP
[](https://www.python.org/downloads/)
[](https://modelcontextprotocol.io/)
[](https://opensource.org/licenses/MIT)
[](https://github.com/astral-sh/uv)
MCP server for **bidirectional Slack communication** with Claude Code. Get notified when tasks complete, and respond to Claude's questions directly from Slack.
## Quick Start
```bash
# Add to Claude Code (one command)
claude mcp add slack-notifier -s user \
-e SLACK_BOT_TOKEN=xoxb-your-token \
-e SLACK_DEFAULT_CHANNEL=YOUR-CHANNEL-ID \
-- uvx slack-notifier-mcp@latest
```
## Features
- **Send Messages** - Send messages with optional urgency levels and thread support
- **Ask & Wait** - Ask questions and wait for replies via Slack threads
- **Bidirectional** - Reply to Claude from Slack, get responses back in your terminal
- **Urgency Levels** - Normal, important, and critical notifications with appropriate formatting
## Slack App Setup
Before using this server, you need to create a Slack app:
1. Go to [api.slack.com/apps](https://api.slack.com/apps) and click **Create New App**
2. Choose **From scratch**, name it (e.g., "Claude Code"), and select your workspace
3. Go to **OAuth & Permissions** in the sidebar
4. Under **Scopes > Bot Token Scopes**, add:
- `chat:write` - Send messages
- `channels:history` - Read public channel messages
- `groups:history` - Read private channel messages
- `im:history` - Read DM messages
- `users:read` - Get user display names
5. Click **Install to Workspace** at the top
6. Copy the **Bot User OAuth Token** (starts with `xoxb-`)
To get your default channel ID:
- Open Slack, right-click the channel, and select **View channel details**
- At the bottom, copy the **Channel ID** (starts with `C`)
## Installation
### Claude Code (Recommended)
```bash
claude mcp add slack-notifier -s user \
-e SLACK_BOT_TOKEN=xoxb-your-token \
-e SLACK_DEFAULT_CHANNEL=YOUR-CHANNEL-ID \
-- uvx slack-notifier-mcp@latest
```
### VS Code
```bash
code --add-mcp '{"name":"slack-notifier","command":"uvx","args":["slack-notifier-mcp@latest"],"env":{"SLACK_BOT_TOKEN":"xoxb-your-token","SLACK_DEFAULT_CHANNEL":"YOUR-CHANNEL-ID"}}'
```
### Other MCP Clients
<details>
<summary><strong>Claude Desktop</strong></summary>
Add to your Claude Desktop config:
- **macOS**: `~/Library/Application Support/Claude/claude_desktop_config.json`
- **Windows**: `%APPDATA%\Claude\claude_desktop_config.json`
- **Linux**: `~/.config/Claude/claude_desktop_config.json`
```json
{
"mcpServers": {
"slack-notifier": {
"command": "uvx",
"args": ["slack-notifier-mcp@latest"],
"env": {
"SLACK_BOT_TOKEN": "xoxb-your-token",
"SLACK_DEFAULT_CHANNEL": "YOUR-CHANNEL-ID"
}
}
}
}
```
</details>
<details>
<summary><strong>Cursor</strong></summary>
1. Go to **Settings → MCP → Add new MCP Server**
2. Select `command` type
3. Enter command: `uvx slack-notifier-mcp@latest`
4. Add environment variables for `SLACK_BOT_TOKEN` and `SLACK_DEFAULT_CHANNEL`
Or add to `~/.cursor/mcp.json`:
```json
{
"mcpServers": {
"slack-notifier": {
"command": "uvx",
"args": ["slack-notifier-mcp@latest"],
"env": {
"SLACK_BOT_TOKEN": "xoxb-your-token",
"SLACK_DEFAULT_CHANNEL": "YOUR-CHANNEL-ID"
}
}
}
}
```
</details>
<details>
<summary><strong>Windsurf / Other MCP Clients</strong></summary>
Any MCP-compatible client can use slack-notifier:
```json
{
"mcpServers": {
"slack-notifier": {
"command": "uvx",
"args": ["slack-notifier-mcp@latest"],
"env": {
"SLACK_BOT_TOKEN": "xoxb-your-token",
"SLACK_DEFAULT_CHANNEL": "YOUR-CHANNEL-ID"
}
}
}
}
```
</details>
### Local Development
```bash
git clone https://github.com/strand-ai/slack-notifier-mcp.git
cd slack-notifier-mcp
uv sync
uv run slack-notifier-mcp
```
## MCP Tools
### `send`
Send a message to Slack with optional urgency and thread support.
```python
# Simple message
send(message="Build completed successfully")
# With urgency (adds formatting and @here for critical)
send(
message="Server is down!",
urgency="critical" # or "normal", "important"
)
# Reply in a thread
send(
message="Done with the first step, moving on...",
thread_ts="1234567890.123456"
)
# Mention user
send(
message="Need your attention",
mention_user=True
)
```
**Parameters:**
- `message` (required): Message text (supports Slack mrkdwn)
- `channel` (optional): Channel ID or name (uses default if not set)
- `thread_ts` (optional): Thread timestamp to reply in a thread
- `urgency` (optional): `normal`, `important`, or `critical`
- `mention_user` (optional): If true, @mentions the configured user
### `ask_user`
Send a question and wait for the user's reply.
```python
ask_user(
question="Should I use PostgreSQL or SQLite for the database?",
context="Setting up the backend for the new API",
timeout_minutes=10
)
# Returns: {"success": True, "reply": "Use PostgreSQL", ...}
```
**Parameters:**
- `question` (required): The question to ask
- `channel` (optional): Channel ID or name
- `context` (optional): Additional context about what you're working on
- `timeout_minutes` (optional): How long to wait (default 5, max 30)
### `get_thread_replies`
Check for new replies in a thread.
```python
get_thread_replies(
channel="YOUR-CHANNEL-ID",
thread_ts="1234567890.123456",
since_ts="1234567891.000000" # Only newer messages
)
```
## Environment Variables
| Variable | Required | Description |
|----------|----------|-------------|
| `SLACK_BOT_TOKEN` | Yes | Bot token from Slack app (xoxb-...) |
| `SLACK_DEFAULT_CHANNEL` | No | Default channel for notifications |
## Example Usage
Tell Claude Code:
> "Notify me on Slack when the tests finish running"
> "Ask me on Slack whether to proceed with the database migration"
> "Send a Slack notification if any errors occur while I'm away"
## Debugging
Run the MCP inspector to test tools:
```bash
npx @anthropics/mcp-inspector uvx slack-notifier-mcp@latest
```
Check if your token works:
```bash
curl -H "Authorization: Bearer xoxb-your-token" \
https://slack.com/api/auth.test
```
## Development
```bash
# Install with dev dependencies
uv sync --extra dev
# Run tests
uv run pytest
# Format code
uv run black slack_mcp
uv run ruff check slack_mcp --fix
```
## License
MIT
