Beginner Outlook Calendar Summary with OpenAI

A step-by-step demo that shows how to pull your Outlook calendar events for the week and ask GPT-4o to write a short summary.
Along the way you’ll practice basic data-transform nodes (Code, Filter, Aggregate) and see where to attach the required API credentials.

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1️⃣ Manual Trigger — Run Workflow

Why

Lets you click “Execute” in the n8n editor so you can test each change.

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2️⃣ Get Outlook Events — Get many events

1. Node type: Microsoft Outlook → Event → Get All
2. Fields selected: subject, start
3. API setup (inside this node):
   • Click Credentials ▸ Microsoft Outlook OAuth2 API
   • If you haven’t connected before:
     1. Choose “Microsoft Outlook OAuth2 API” → “Create New”.
     2. Sign in and grant the Calendars.Read permission.
     3. Save the credential (e.g., “Microsoft Outlook account”).
4. Output: A list of events with the raw ISO start time.

Teaching moment: Outlook returns a full dateTime string. We’ll normalize it next so it’s easy to filter.

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3️⃣ Normalize Dates — Convert to Date Format

// Code node contents
return $input.all().map(item => {
  const startDateTime = new Date(item.json.start.dateTime);
  const formattedDate = startDateTime.toISOString().split('T')[0]; // YYYY-MM-DD
  return { json: { ...item.json, startDateFormatted: formattedDate } };
});

### 4️⃣ Filter the Events Down to *This* Week  
After we’ve normalised the `start` date-time into a simple `YYYY-MM-DD` string, we drop in a **Filter** node.  
Add one rule for every day you want to keep—for example `2025-08-07` **or** `2025-08-08`. Rows that match any of those dates will continue through the workflow; everything else is quietly discarded.  

*Why we’re doing this:* we only want to summarise tomorrow’s and the following day’s meetings, not the entire calendar.

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### 5️⃣ Roll All Subjects Into a Single Item  
Next comes an **Aggregate** node. Tell it to aggregate the `subject` field and choose the option *“Only aggregated fields.”*  
The result is one clean item whose `subject` property is now a tidy list of every meeting title. It’s far easier (and cheaper) to pass one prompt to GPT than dozens of small ones.

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### 6️⃣ Turn That List Into Plain Text  
Insert a small **Code** node right after the aggregation:

```js
return [{
  json: {
    text: items
      .map(item => JSON.stringify(item.json))
      .join('\n')
  }
}];

Need a Hand?
I’m always happy to chat automation, n8n, or Outlook API quirks.

Robert Breen – Automation Consultant & n8n Instructor
📧 [email protected] | LinkedIn