Slack MCP Setup

How to set up the Slack MCP server (slack-mcp-server) to read and post messages from Claude Code.

Token type

Always use a user token (xoxp-). Do not use bot tokens (xoxb-) — they require the bot to be invited to every channel, cannot list channels the bot isn’t in, and post as the bot instead of you.

Env var	Posts as	Channel access	Expires
SLACK_MCP_XOXP_TOKEN	You	All channels you’re a member of	No

Creating a Slack app and getting a user token

1. Create or edit a Slack app

Go to api.slack.com/apps. Either create a new app or edit an existing one.

If creating from scratch: Create New App > From an app manifest > select your workspace > paste the manifest below.

2. App manifest

{
  "display_information": {
    "name": "Claude Code",
    "description": "Claude Code Slack integration"
  },
  "oauth_config": {
    "scopes": {
      "bot": [],
      "user": [
        "channels:read",
        "channels:history",
        "chat:write",
        "groups:read",
        "groups:history",
        "im:read",
        "im:write",
        "im:history",
        "mpim:read",
        "mpim:history",
        "users:read",
        "search:read"
      ]
    }
  },
  "settings": {
    "org_deploy_enabled": false,
    "socket_mode_enabled": false,
    "token_rotation_enabled": false
  }
}

If editing an existing app: go to App Manifest (JSON tab), merge the user scopes above, save, and reinstall.

3. Install to workspace

Go to Install App (or OAuth & Permissions > Reinstall to Workspace if updating scopes). Authorize the app.

4. Copy the user token

After installation, go to OAuth & Permissions. Copy the User OAuth Token (starts with xoxp-).

5. Store the token

Add it to your shell config (e.g. ~/.zshrc):

export SLACK_QRAFT_USER_TOKEN="xoxp-..."

Then source ~/.zshrc.

6. Configure .mcp.json

{
  "mcpServers": {
    "slack-qraft": {
      "command": "/opt/homebrew/bin/slack-mcp-server",
      "args": ["-t", "stdio"],
      "env": {
        "SLACK_MCP_XOXP_TOKEN": "${SLACK_QRAFT_USER_TOKEN}",
        "SLACK_MCP_ADD_MESSAGE_TOOL": "true"
      }
    }
  }
}

7. Restart Claude Code

The MCP server is initialized at startup. Restart Claude Code to pick up the new token.

Optional env vars

Env var	Description
SLACK_MCP_ADD_MESSAGE_TOOL	true to enable posting messages (disabled by default to prevent spam)
SLACK_MCP_REACTION_TOOL	true to enable emoji reactions, or comma-separated channel IDs to limit
SLACK_MCP_MARK_TOOL	true to enable marking channels as read
SLACK_MCP_ATTACHMENT_TOOL	true to enable downloading attachments

Multiple workspaces

Create one Slack app per workspace, each with its own token and MCP server entry. Example with two workspaces:

{
  "mcpServers": {
    "slack-qraft": {
      "command": "/opt/homebrew/bin/slack-mcp-server",
      "args": ["-t", "stdio"],
      "env": {
        "SLACK_MCP_XOXP_TOKEN": "${SLACK_QRAFT_USER_TOKEN}",
        "SLACK_MCP_ADD_MESSAGE_TOOL": "true"
      }
    },
    "slack-episto": {
      "command": "/opt/homebrew/bin/slack-mcp-server",
      "args": ["-t", "stdio"],
      "env": {
        "SLACK_MCP_XOXP_TOKEN": "${SLACK_EPISTO_USER_TOKEN}",
        "SLACK_MCP_ADD_MESSAGE_TOOL": "true"
      }
    }
  }
}