Slack Local MCP

What is Slack Local MCP?

Slack Local MCP is a lightweight Model Context Protocol (MCP) server that lets you automate Slack actions using cookie-based authentication instead of creating a Slack app or bot. It’s designed for personal automation and local development, requiring no OAuth tokens or complex app setup.

How to use Slack Local MCP?

Install via npx -y slack-local-mcp or manually with Node.js 18+. Configure your MCP settings with environment variables SLACK_COOKIE_D (your Slack d cookie value) and SLACK_WORKSPACE_URL. Then invoke natural language commands through your MCP client to send messages, fetch conversations, add reactions, and more.

Key features of Slack Local MCP

• Send messages to channels, DMs, and threads
• Schedule messages with Slack’s native scheduling (requires bot token)
• Fetch channel messages and thread replies for AI summarization
• Add emoji reactions to messages
• Cookie-based authentication for quick setup
• No Slack app or bot registration needed

Use cases of Slack Local MCP

• Summarize recent channel messages with an AI assistant
• Send or schedule daily team standup reminders
• Manage thread conversations by fetching and replying to discussions
• React to messages automatically based on rules or prompts

FAQ from Slack Local MCP

How do I get my Slack cookie for authentication?

Open Slack in your browser, go to Developer Tools → Application/Storage → Cookies → https://app.slack.com, find the cookie named d, and copy its URL-encoded value (starts with xoxd-). Keep it private.

Does Slack Local MCP support message scheduling?

Scheduling uses Slack’s native API and requires a bot token (xoxb-). It is not available with cookie authentication (xoxd-). The tool will return an error when used with cookie auth.

How long does the cookie last?

Cookies typically last for weeks or months. They become invalid if you log out of Slack or clear browser data. The server shows an authentication error when the cookie expires.

What are the runtime requirements?

Node.js 18+ and an active Slack workspace. No external dependencies beyond the MCP client that runs this server.

Is this suitable for production or team deployments?

The README recommends using OAuth-based Slack MCP servers for production or team-wide use. Cookie authentication is ideal for personal automation and local development.