Auto-Categorize Outlook Emails with AI in n8n

How It Works

1. Trigger: The workflow starts with the Microsoft Outlook Trigger node, polling your inbox every minute for new emails.

2. Extract & Clean Email Content: The email’s key fields (from, subject, isRead, body) are extracted. The body is converted from HTML to Markdown, then sanitized to plain text for reliable AI processing.

Node Setup Details:

 * **Microsoft Outlook Trigger**

   * **Resource:** Message
   * **Operation:** Trigger on new email
   * **Fields to Output:** from, subject, isRead(optional), body
   * **Folders to Include:** (Set to your Inbox or specific folder IDs)
 * **Markdown Node**

   * **Input:** `{{$json["body"]["content"]}}` (HTML email body)
   * **Output Key:** `Email Body Markdown`
   * **Purpose:** Converts HTML to Markdown for easier downstream processing.
 * **Sanitize Node (Code Node)**

   * **Input:** `Email Body Markdown` from previous node
   * **Purpose:** Cleans up Markdown, strips images, links, HTML tags, table formatting, and truncates to 4000 characters.
   * **Sample JS Code:**
        
                    // Get the markdown content from the previous node
        const markdownContent = $input.item.json["Email Body Markdown"];
        
        

3. Setup AI tools

 * Move message and Get Folders Outlook tools are required, get contacts is optional.
 * Set each field in the tools to "defined automatically by the model" and describe each field so the model understands how to use it.
 * OpenRouter or other LLM models tool: You can use any client for this, but make sure to use a model that does well with tool calls (Claude, GPT-4.1, Gemini 2.5 Pro, etc.).

Best Practices & Notes

• AI Prompt Engineering: The AI is instructed to be conservative—never move emails from real people or saved contacts, and always explain its reasoning if it doesn’t move a message.
• This automation only works for NEW incoming messages.
• Inbox Zero: This system is designed to help you achieve and maintain Inbox Zero by keeping only actionable items in your main inbox.
• Customization: You can adjust the folder logic, add more categories, or tweak the AI prompt for your specific needs.
• Privacy: All processing happens within your n8n instance; no email data is stored outside your environment except for the AI call (which only receives sanitized, minimal content).