Build Your Second Brain: Automated Knowledge Capture with n8n + Notion

What Is a Second Brain — and Why Automate It?

A Second Brain is a personal knowledge management system: a single place where everything you read, watch, think, and discover gets stored, organised, and made retrievable. The concept was popularised by productivity author Tiago Forte, and it solves a problem every knowledge worker has — you consume enormous amounts of useful information every day, and almost none of it sticks.

The problem with most Second Brain setups is that they require manual effort. You have to remember to save things. You have to tag them. You have to write summaries. And when you are busy, none of that happens.

This guide automates the capture layer entirely. By the end, you will have a system that:

• Captures web articles, YouTube videos, and PDF links automatically from your phone or browser
• Generates an AI summary of each item so you get the key points without reading everything
• Tags and categorises content based on the topic
• Stores everything in a structured Notion database with full search capability

You will still read and think — the automation just makes sure nothing slips through.

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What You Will Need

Before starting, make sure you have:

• An n8n account. The cloud version works fine. If you are self-hosting, this guide assumes n8n v1.0 or later.
• A Notion account with a workspace you control. You will need to create an integration.
• An OpenAI API key (or Claude API key) for the AI summarisation step. A free tier account works for personal use.
• A way to send URLs to n8n — we will use a simple webhook that works with any browser extension or phone shortcut.

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Step 1: Set Up Your Notion Database

First, create the database that will store everything.

In Notion, create a new full-page database. Name it Knowledge Base or whatever feels right.

Add the following properties to the database:

Property Name	Property Type	Purpose
Title	Title	The title of the item (auto-filled)
URL	URL	The source link
Type	Select	Article / Video / Podcast / Note / Other
Topic	Multi-select	Tags for filtering
Summary	Text	AI-generated summary
Status	Select	Unread / Reading / Done / Reference
Date Added	Created time	Auto-filled by Notion
Source	Text	Where this came from

Save the database and copy its ID from the URL. The ID is the string of characters after the last slash and before the question mark in the Notion URL.

Screenshot placeholder: Notion database with all properties configured

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Step 2: Create a Notion Integration

Go to notion.so/my-integrations and create a new integration.

Name it n8n Second Brain and give it read and write access to content.

Copy the Internal Integration Token — this is your Notion API key for n8n.

Back in your Notion database, click the three-dot menu in the top right → Add connections → select your new integration.

Screenshot placeholder: Notion integrations page showing the new integration

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Step 3: Build the n8n Workflow

Open n8n and create a new workflow.

Node 1 — Webhook (Trigger)

Add a Webhook node. Set the method to POST. Copy the webhook URL — you will use this to send content to the workflow.

Set the response mode to “Respond immediately” so your phone or browser does not hang waiting for a response.

Node 2 — Set (Prepare Data)

Add a Set node connected to the Webhook. Map the incoming webhook data to clean variables:

• url — the URL being saved
• title — optional title if provided
• notes — any personal note you want to attach

Node 3 — HTTP Request (Fetch Page Content)

Add an HTTP Request node. Use the url variable to fetch the page content. Set the format to text/html. This gives the AI something to summarise.

For YouTube URLs, the HTML will contain the video title and description — enough for a useful summary.

Node 4 — OpenAI (Generate Summary)

Add an OpenAI node (or use the HTTP Request node to call the Claude API directly).

Use this system prompt:

You are a knowledge management assistant. Your job is to read web content and produce a concise, useful summary for a personal knowledge base.

For the content provided, generate:
1. A clear title (if one is not already provided)
2. A 3-5 sentence summary of the key points
3. Three topic tags that describe the subject matter
4. The content type: Article, Video, Podcast, or Other

Respond in JSON format:
{
  "title": "...",
  "summary": "...",
  "tags": ["...", "...", "..."],
  "type": "..."
}

Pass the fetched page content as the user message.

Node 5 — Code (Parse JSON Response)

Add a Code node to parse the JSON response from the AI into individual variables: title, summary, tags, type.

Node 6 — Notion (Create Database Item)

Add a Notion node. Select the Create database item operation.

Map the fields:

• Title → title from the AI output (or fallback to webhook title)
• URL → url from webhook
• Summary → summary from AI
• Topic → tags from AI
• Type → type from AI
• Status → set to “Unread” as default
• Source → set to “n8n Webhook”

Screenshot placeholder: Complete n8n workflow showing all six nodes connected

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Step 4: Set Up the Capture Trigger

Now you need a way to send URLs to your webhook from anywhere.

On Desktop (Browser Extension):
Install the Zapier Browser Extension or use a simple bookmarklet. Alternatively, the n8n Chrome extension (if available) sends the current page URL directly to a webhook.

The simplest approach: create a bookmarklet that sends the current URL to your webhook. Paste this into a new bookmark:

javascript:fetch('YOUR_WEBHOOK_URL',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({url:location.href,title:document.title})});alert('Saved to Second Brain');

Replace YOUR_WEBHOOK_URL with your n8n webhook URL.

On iPhone (Shortcuts App):
Create a new Shortcut that uses the Get URLs from Input action, followed by a Get Contents of URL action configured as a POST request to your webhook URL, passing {"url": "[URL]", "title": "[Page Name]"} as the body.

Add this shortcut to your Share Sheet so you can save anything from Safari in two taps.

Screenshot placeholder: iPhone Shortcuts configuration screen

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Step 5: Test the Workflow

Activate your n8n workflow. Then save a URL using your bookmarklet or phone shortcut.

Check n8n — you should see the workflow execute. Check each node to make sure data is flowing correctly.

Open Notion — the item should appear in your database with the AI-generated title, summary, and tags already filled in.

Common issues:

• Webhook not receiving data: Make sure the workflow is activated, not just saved.
• AI summary is empty: Check your OpenAI API key is valid and has credits.
• Notion item not created: Confirm the integration has been connected to the specific database, not just the workspace.

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What to Do Next

Once this is working, consider these extensions:

• Add an email capture node: Forward newsletters to a dedicated email address and have n8n capture them automatically.
• Add a Readwise integration: If you use Readwise for highlights, pipe your highlights into the same Notion database.
• Add a weekly digest: Use n8n to query your Notion database every Sunday and email you a summary of everything you saved that week but marked Unread.
• Add Claude for deeper analysis: Instead of just summarising, prompt the AI to connect each new item to existing notes in your database.

Your Second Brain is now on autopilot. The capture layer handles itself — you just have to think.