Gated MCP Server in n8n for Claude & ChatGPT CRM Read/Write Tools

Secure MCP Server in n8n so Claude & ChatGPT can safely read/write your business data

This n8n automation exposes an authenticated MCP server endpoint that lets MCP clients (like Claude Desktop or ChatGPT) look up customer and order information and write back notes, tasks, meetings, and email drafts—using Google Sheets, Google Calendar, Gmail, and Slack.

What this workflow does

• Runs a gated MCP server endpoint in n8n, protected by a header token, and waits for tool calls from an MCP client.
• Reads CRM-style data from Google Sheets so the client can:
  • Find customer records
  • Check order status
  • Review stock levels
  • View open invoices
• Pulls upcoming meetings from Google Calendar within a provided time window, with an optional text query.
• Writes back follow-up information by appending customer notes and follow-up tasks into dedicated Google Sheets tabs (Customers, Orders, Inventory, Invoices, Notes, Tasks).
• Creates customer email drafts in Gmail and posts notifications to a Slack channel for your account team.

Use cases

• Support or sales staff use Claude/ChatGPT to quickly answer: “What’s the status of this order, and what invoices are open?”
• During account management, the AI drafts a Gmail reply and logs next steps (notes + tasks) into Google Sheets.
• When planning follow-ups, the AI retrieves Google Calendar meetings for a time range and schedules outreach accordingly.
• Your team receives Slack notifications whenever an AI-generated draft or follow-up is created.

Technical details

• MCP server authentication: header token with a long random value
• Google integrations: OAuth2 for Google Sheets and Google Calendar
• Messaging: OAuth2 for Gmail (drafts) and Slack (channel notifications)
• n8n nodes referenced: if, code, gmail, slack, switch, sticky note

After activation, copy the MCP server URL from the trigger and configure it in your MCP client along with the same header token.