Slack MCP

Slack MCP

What This Does

Enables Claude Code to list channels, read messages, post messages, and interact with Slack.

Source

• Docker Hub: https://hub.docker.com/r/mcp/slack

• Docker: mcp/slack

• Alternative: https://github.com/korotovsky/slack-mcp-server

Prerequisites

• Docker Desktop installed

• Access to Slack workspace (admin or ability to install apps)

• Slack Bot Token and Team ID

Step 1: Create Local Config Folder

mkdir -p ~/.config/mcp/slack

Step 2: Get Credentials

Create Slack App

1. Go to https://api.slack.com/apps

2. Click Create New App

3. Choose From scratch

4. Name: "MCP Bot"

5. Select your workspace

6. Click Create App

Configure Bot Permissions

1. Go to OAuth & Permissions

2. Under Scopes → Bot Token Scopes, add:

Scope	Purpose
channels:history	Read public channel messages
channels:read	List public channels
chat:write	Post messages
groups:history	Read private channel messages
groups:read	List private channels
im:history	Read DM messages
im:read	List DMs
im:write	Send DMs
reactions:write	Add reactions
users:read	List users
users.profile:read	Read user profiles

Install App to Workspace

1. Go to OAuth & Permissions

2. Click Install to Workspace

3. Click Allow

4. Copy the Bot User OAuth Token (starts with xoxb-)

Get Team ID

Option A - From browser:

1. Open Slack in browser

2. URL: https://app.slack.com/client/TXXXXXXXX/...

3. The TXXXXXXXX part is your Team ID

Option B - From desktop app:

1. Click workspace name → Settings & administration → Workspace settings

2. Team ID shown in URL

Step 3: Save Credentials Locally

Create ~/.config/mcp/slack/.env:

cat > ~/.config/mcp/slack/.env << 'EOF'
SLACK_BOT_TOKEN=xoxb-your-bot-token-here
SLACK_TEAM_ID=TXXXXXXXX
EOF

Replace with your actual values.

Step 4: Pull Docker Image

docker pull mcp/slack

Step 5: Test the Connection

source ~/.config/mcp/slack/.env && docker run --rm \
  -e SLACK_BOT_TOKEN="$SLACK_BOT_TOKEN" \
  -e SLACK_TEAM_ID="$SLACK_TEAM_ID" \
  mcp/slack --help

Step 6: Add to Claude Code

Add to ~/.claude/settings.json:

{
  "mcpServers": {
    "slack": {
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "--env-file", "${HOME}/.config/mcp/slack/.env",
        "mcp/slack"
      ]
    }
  }
}

Note: If ${HOME} doesn't expand, use absolute path:

{
  "mcpServers": {
    "slack": {
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "--env-file", "/Users/yourname/.config/mcp/slack/.env",
        "mcp/slack"
      ]
    }
  }
}

Step 7: Verify It Works

Restart Claude Code and test:

List all public Slack channels

Expected: List of channels in your workspace.

Available Tools

Tool	Description
slack_list_channels	List public channels
slack_post_message	Post a new message to a channel
slack_reply_to_thread	Reply to a specific thread
slack_add_reaction	Add emoji reaction to a message
slack_get_channel_history	Get recent messages from a channel
slack_get_thread_replies	Get all replies in a thread
slack_get_users	List workspace users
slack_get_user_profile	Get specific user's profile

Invite Bot to Channels

Before the bot can access a channel:

1. Go to the channel in Slack

2. Type /invite @MCP Bot (use your bot's name)

3. Or: Channel settings → Integrations → Add apps

Limiting Channel Access (Optional)

For security, limit which channels the bot can access:

# Add to .env
SLACK_CHANNEL_IDS=C01234567,C89012345

Get channel IDs:

1. Right-click channel in Slack

2. Click View channel details

3. Scroll to bottom → Channel ID

Troubleshooting

Issue	Solution
"not_authed"	Check bot token is correct and starts with xoxb-
"channel_not_found"	Invite bot to the channel first
"missing_scope"	Add required scope in Slack app settings, reinstall app
"invalid_auth"	Token may be revoked, generate new one
Can't see private channels	Add groups:read scope, invite bot to channel
Can't post messages	Add chat:write scope
env-file not found	Use absolute path instead of ${HOME}