Building a second brain with AI: turn your email and documents into memory

Your head isn't built to remember everything: decisions made by email, the figures in a quote, what a client said three months ago. A "second brain" is an external system that keeps all of that for you. With AI, it no longer just stores: it answers.

What is a second brain?

The term was popularised by Tiago Forte in *Building a Second Brain*. The idea: get useful information out of your head and into a trusted system, to free your attention and find what you need at the right time.

Forte proposes the four-step CODE method: Capture what has value, Organise it by project, Distil the essentials, Express them by reusing them in your work.

It's the natural sequel to GTD: GTD manages your actions, the second brain manages your knowledge.

Your inbox is already a (messy) second brain

Most professionals have already captured the essentials without realising it: decisions, prices, contacts, commitments — it's all in the inbox and a few document folders.

The problem isn't capture, it's retrieval. Finding a piece of information means remembering the right keyword, the right sender, the right time period. So you reread, you dig, you ask again.

That's a big part of email's mental load: knowing the information exists somewhere without being able to reach it quickly.

What AI changes

With a personal RAG, you no longer need to file everything perfectly. You ask a question in plain language; the AI finds the relevant passages and answers with its sources.

The CODE steps get lighter: capture happens by connecting your inbox and adding your documents, organising is partly replaced by search, distilling is helped by summaries. What's left is the essential part: expressing — deciding and acting.

Beware the trap: a second brain full of noise gives noisy answers. Keep the habit of deleting and reducing noise at the source.

Virtus Lever as a second brain

Virtus Lever connects your emails, calendar, documents and notes, and lets you query them from its AI chat, with sources shown. You can add PDFs, Word, Excel, PowerPoint or text files, or write a note directly.

The connection is read-only, data is hosted in the EU, and a data processing agreement (DPA) is available. Your second brain stays yours.

And because a second brain should also help you act, Lever shows you the highest-leverage email each morning. That's how it becomes a true AI personal assistant.