Slack MCP

Read and respond to Slack from Claude. Works as an MCP server (for Claude Desktop/Claude Code) and as a standalone CLI (for GitHub Actions).

Features

Multi-workspace support - Configure multiple Slack workspaces
Read tools - Summarize activity, list channels, read messages, search
Write tools - Send messages, reply to threads, add reactions
Standalone CLI - Generate markdown summaries for GitHub Actions

Installation

1. Create Slack App(s)

For each workspace you want to connect:

Go to https://api.slack.com/apps → Create New App → From manifest
Select your workspace
Paste this manifest:

display_information:
  name: Claude Slack Reader
  description: Read and respond to Slack from Claude
oauth_config:
  scopes:
    user:
      # Read
      - channels:history
      - channels:read
      - groups:history
      - groups:read
      - im:history
      - im:read
      - mpim:history
      - mpim:read
      - users:read
      - search:read       # slack_search
      # Write
      - chat:write        # send messages to channels + DMs
      - reactions:write   # add emoji reactions
      - files:write       # upload files / images
      - im:write          # open a NEW DM with someone you've never messaged (existing DMs work without this)
settings:
  org_deploy_enabled: false
  socket_mode_enabled: false
  token_rotation_enabled: false

Click Install to Workspace → Allow
Copy the User OAuth Token (starts with xoxp-)

Note: Slack requires a separate app per workspace (public distribution requires Slack approval).

2. Configure Tokens

Create ~/.mcp-auth/slack/config.json:

{
  "workspaces": {
    "work": {
      "name": "Work Slack",
      "token": "xoxp-your-token-here",
      "priority": 1
    },
    "research": {
      "name": "Research Group",
      "token": "xoxp-your-token-here",
      "priority": 2
    }
  },
  "default_workspace": "work"
}

Or use environment variables:

export SLACK_USER_TOKEN=xoxp-...           # Single workspace
export SLACK_TOKEN_WORK=xoxp-...           # Multiple workspaces
export SLACK_TOKEN_RESEARCH=xoxp-...

3. Install Dependencies

cd ~/src/slack-mcp
pip install -r requirements.txt

4. Add to Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "slack": {
      "command": "python3",
      "args": ["/path/to/slack-mcp/server.py"]
    }
  }
}

Restart Claude Desktop.

Project Structure

slack-mcp/
├── src/
│   ├── config.py          # Multi-workspace configuration
│   ├── slack_client.py    # Slack API wrapper (read + write)
│   ├── summarizer.py      # Message categorization
│   └── mcp_server.py      # MCP server with tools
├── server.py              # Entry point for MCP server
├── slack_summary.py       # Standalone CLI
├── requirements.txt
├── pyproject.toml
└── .github/
    └── workflows/
        └── daily-summary.yml

MCP Tools

Read Tools

Tool	Description
`slack_summary`	Overview of DMs, mentions, channel activity. Use `mode: "quick"` (default) or `mode: "full"`
`slack_channels`	List all channels (filter by type: `all`, `channels`, `dms`, `groups`)
`slack_channel`	Read messages from a specific channel
`slack_thread`	Read messages in a thread
`slack_search`	Search messages
`slack_unread`	Get unread message counts
`slack_workspaces`	List configured workspaces

Write Tools

Tool	Description
`slack_send`	Send message to channel or DM
`slack_reply`	Reply in a thread
`slack_react`	Add emoji reaction

Example Usage in Claude

"What's happening in my Slack?"
→ Uses slack_summary with quick mode

"Show me the #engineering channel"
→ Uses slack_channel

"Reply to that thread saying I'll review it tomorrow"
→ Uses slack_reply

"Add a thumbsup to that message"
→ Uses slack_react

Standalone CLI

Generate markdown summaries without Claude:

# Print summary to stdout
python slack_summary.py

# Save to file
python slack_summary.py --output slack-summary.md

# Look back 48 hours
python slack_summary.py --hours 48

# Specific workspace
python slack_summary.py --workspace work

# Action items only
python slack_summary.py --action-items-only

GitHub Actions Workflow

The included workflow runs daily and commits a summary:

# .github/workflows/daily-summary.yml
name: Daily Slack Summary

on:
  schedule:
    - cron: '0 12 * * *'  # 7 AM EST
  workflow_dispatch:

jobs:
  summarize:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.11'
      - run: pip install -r requirements.txt
      - env:
          SLACK_USER_TOKEN: ${{ secrets.SLACK_USER_TOKEN }}
        run: python slack_summary.py --output slack-summary.md
      - run: |
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git config user.name "github-actions[bot]"
          git add slack-summary.md
          git diff --quiet --staged || git commit -m "Daily Slack summary [skip ci]"
          git push

Add your token as a repository secret: Settings → Secrets → Actions → New repository secret → SLACK_USER_TOKEN

Configuration Sync

To sync config across machines, symlink to a cloud folder:

mkdir -p ~/.mcp-auth/slack
ln -sf ~/Dropbox/mcp-auth/slack/config.json ~/.mcp-auth/slack/config.json
# or Box, iCloud, etc.

Performance

Quick mode (default): ~4 seconds - scans recent DMs and channels
Full mode: ~20 seconds - detailed scan of all activity
Cached calls: ~1.5 seconds - conversation list cached for 5 minutes

Requirements

Python 3.10+
slack-sdk - Slack API client
mcp - Model Context Protocol server

Slack MCP

Slack MCP

Features

Installation

1. Create Slack App(s)

2. Configure Tokens

3. Install Dependencies

4. Add to Claude Desktop

Project Structure

MCP Tools

Read Tools

Write Tools

Example Usage in Claude

Standalone CLI

GitHub Actions Workflow

Configuration Sync

Performance

Requirements

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