n8n Automated Email Triage with Gmail, GPT-4o, and Slack

Periodically scan Gmail inbox, classify urgency and intent with GPT-4o, auto-label emails, and push summaries to Slack

Who

Professionals, team leads, or founders managing high email volume

You get

Automatically fetch new emails on a schedule, AI-classify them with Gmail labels, instantly alert high-urgency items to Slack, and summarize the rest in a digest

You need

n8n · gmail · google-sheets · slack

Steps

1. Connect accounts

   Configure four credentials in n8n: Gmail (OAuth2), Slack (OAuth2), Google Sheets (OAuth2), and OpenAI (API Key). Ensure each credential is Active.

2. Create Gmail labels

   Go to Gmail Settings → Labels and create labels in this format: AI Agent/To Respond, AI Agent/Awaiting Reply, AI Agent/Notification, AI Agent/Marketing, etc. These labels are used by the workflow for intent-based auto-tagging.

3. Create Google Sheets workbook

   Create a new Google Sheet named something like N8N - Emails. Add two tabs: Sheet1 (stores all processed emails) and Sheet2 (stores only the latest batch for digest). Both tabs need header row: From | Summary | Intent | Category | TimeStamp | Urgency.

4. Import workflow and configure Slack channel

   Import the workflow.json into your n8n instance. Verify each node is linked to the correct active credentials. In the Slack nodes (Send a message2 and Send a message3), select the target channel for high-urgency alerts and digest summaries.

5. Adjust schedule interval

   Review the Schedule Trigger1 node. The source workflow.json sets it to every 4 hours (hoursInterval: 4), while the description mentions both hourly and every-4-hours. Adjust to your preference: 30 min, 1 hour, 2 hours, or 4 hours.

6. Run a test

   Execute the workflow manually once to verify: emails are fetched, Gmail labels are applied correctly, Slack notifications trigger, and data is logged to Google Sheets.

7. Activate the workflow

   Once testing looks correct, activate the workflow. It will run automatically on the set schedule.

8. Trigger and fetch emails

   The Schedule Trigger starts on schedule. The workflow first fetches the Gmail label list, then pulls all emails from the last 4 hours (receivedAfter computed dynamically).

9. GPT-4o email analysis

   Each email is sent to the OpenAI node (Message a model1) using gpt-4o-mini. The prompt requests pure JSON output with summary, urgency, category, and intent fields.

   Execution prompt · Source text。n8n OpenAI node Message a model1 messages.values[0].content field

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   =You're an email assistant for a busy startup founder. Classify the email content into the following fields and return **only raw JSON** (no markdown):
   
   {
     "summary": [Short summary of the email in 1 sentence],
     "urgency": [High, Medium, Low],
     "category": [Investor, Customer, Support, Spam, Other],
     "intent": ["To respond", "Awaiting reply", "FYI", "Notification", "Meeting update", "Marketing"]
   }
   
   The descriptions of the intents are as follows:
   1. To respond: Emails you need to respond to
   
   2.FYI: Emails that don't require your response, but are important
   
   3. Notification: Automated updates from tools you use or Team chats in tools like Google Docs or Microsoft Office
   
   4. Meeting update: Calendar updates from Zoom, Google Meet, etc
   
   5. Awaiting reply: Emails you're expecting a reply to
   
   6. Actioned: Email threads that have been resolved
   
   7. Marketing: Marketing or cold emails
   
   Analyze the following email:
   
   Subject: {{ $json.Subject }}
   Body: {{ $json.snippet }}
   
   Return only valid JSON with no extra formatting.

10. Parse intent and apply labels

    The Calculate Intent code node parses GPT output, strips markdown code blocks and smart quotes, maps intent to the corresponding Gmail label ID, and outputs summary, urgency, category, intent, message_id, and label_id.

    Execution prompt · Source text。n8n Code node Calculate Intent jsCode field

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    let raw = $json.message?.content || $json.message || "";
    
    // Remove triple backticks (```json ... ```)
    raw = raw.replace(/```json|```/g, '').trim();
    
    // Fix smart quotes and other formatting problems
    raw = raw.replace(/[“”]/g, '"').replace(/[‘’]/g, "'");
    
    try {
      const parsed = JSON.parse(raw);
    
    
      return {
        summary: parsed.summary || "No summary provided",
        urgency: parsed.urgency || "Unknown",
        category: parsed.category || "Unknown",
        intent: parsed.intent || "Unknown",
        messgae_id: $('Get many messages').item.json.id,
        label_id: $("Get many labels").all().find((item) => item.json.name === `AI Agent/${parsed.intent}`).json.id
      };
    } catch (err) {
      return {
        summary: "⚠️ Failed to parse GPT output",
        urgency: "Unknown",
        category: "Unknown",
        intent: "Unknown",
        error: err.message,
        original: raw
      };
    }

11. High-urgency Slack alert

    An If node checks if urgency equals High. If true, it triggers an immediate Slack alert with sender, summary, urgency, category, and intent.

    Execution prompt · Source text。n8n Slack node Send a message2 text field

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    =*Siddhant, Important Email Detected*  
    From: {{ $('Get many messages').item.json.From }}
    *Summary:* {{ $('Calculate Intent').item.json.summary }} 
    *Urgency:*  {{ $('Calculate Intent').item.json.urgency }} , *Category:* {{ $('Calculate Intent').item.json.category }}, *Intent:* {{ $('Calculate Intent').item.json.intent }}

12. Log to Google Sheets

    All email data is written in parallel to Sheet1 (long-term archive) and Sheet2 (latest batch). Field mapping: From, Summary, Intent, Category, TimeStamp, Urgency.

13. Wait and generate Slack digest

    After a 30-second wait, the workflow reads from Sheet2. The Filter timestamp code node filters entries from the last 0.5 hours with Medium or Low urgency (excluding Marketing). The Daily Digest Preparation node formats the text, and Send a message3 pushes the Slack digest.

    Execution prompt · Source text。n8n Code node Filter timestamp jsCode field

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    const HOURS = 0.5; // hours window
    const now = new Date();
    
    return items.filter(item => {
      const timestamp = item.json.TimeStamp || item.json.timestamp || "";
      const urgency = (item.json.Urgency || item.json.urgency || "").toLowerCase();
    
      if (!timestamp) return false;
    
      const itemDate = new Date(timestamp);
      const hoursDiff = Math.abs((now - itemDate) / 36e5); // 36e5 = 60*60*1000
    
      console.log(hoursDiff)
    
      return hoursDiff <= HOURS && (urgency === "low" || urgency === "medium");
    });

    Execution prompt · Source text。n8n Code node Daily Digest Preparation jsCode field

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    let text = ``;
    
    const medium = [];
    const low = [];
    
    items.forEach(item => {
      const urgency = (item.json.Urgency || "").toLowerCase();
      const intent = (item.json.Intent || "").toLowerCase();
      if (urgency === "medium") {
        medium.push(item);
      } else if (
        urgency === "low" &&
        intent !== "Marketing"
      ) {
        low.push(item);
      }
    });
    
    if (medium.length === 0 && low.length === 0) {
      text += "_No important messages today._";
    } else {
      if (medium.length > 0) {
        text += "*Medium Urgency:*\n";
        medium.forEach((item, index) => {
          text += `*${index + 1}.* ${item.json.Summary || "No summary"}\nFrom: ${item.json.From || "Unknown"}\nUrgency: ${item.json.Urgency || "Unknown"}, Category: ${item.json.Category || "Unknown"}, Intent: ${item.json.Intent || "N/A"}\n\n`;
        });
      }
      if (low.length > 0) {
        text += "*Low Urgency:*\n";
        low.forEach((item, index) => {
          text += `*${index + 1}.* ${item.json.Summary || "No summary"}\nFrom: ${item.json.From || "Unknown"}, Intent: ${item.json.Intent || "N/A"}\n\n`;
        });
      }
    }
    
    return [{ json: { text } }];

    Execution prompt · Source text。n8n Slack node Send a message3 text field

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    =🧠 *Inbox Assistant – Daily Digest*  
    📅 *{{ $now.format("DD : HH:mm") }}*  
    ━━━━━━━━━━━━━━━━━━━
    
    {{ $json.text }}

You are an n8n workflow setup assistant. The user wants to replicate the "Gmail + GPT-4o + Slack automated email triage" template. Assist in this order:
1. Confirm the user has an n8n instance and four credentials (Gmail, Slack, Google Sheets, OpenAI).
2. Guide them to create AI Agent/ prefixed labels in Gmail.
3. Guide them to create the Google Sheets dual-tab structure (Sheet1/Sheet2, six columns).
4. Help import workflow.json and verify node-to-credential mapping.
5. Remind them to check the Schedule Trigger interval (the source has an inconsistency between hourly and every-4-hours).
6. Suggest manual testing before activation.
Do not provide credential secrets; all sensitive info stays in n8n's credential manager.