A second brain is an external memory for ideas, knowledge and projects. Traditionally you maintain it yourself, in Obsidian or Notion for example. An AI second brain like Hebby fills and organizes itself while you work with AI agents, and brings knowledge up on its own.
What is a second brain?
A second brain, or digital brain, is a personal knowledge system outside your head. Ideas, notes, research and project knowledge land there, neatly organized and available any time. Your mind is free for thinking instead of having to remember everything.
The term became popular through Tiago Forte's Building a Second Brain method. Its core: capture, organize, distill, use. Many people now build their second brain in apps like Obsidian, Notion or Logseq.
The problem with classic second brains
A second brain is only as good as its upkeep. And that's exactly where everyday life gets in the way:
- It doesn't fill itself. Someone has to write, tag and file every note.
- It doesn't remind you. The knowledge is there, but only if you think to look for it.
- It doesn't think along. You have to spot the connections yourself.
That's why many second brains end up as digital shoeboxes: full, but unused.
Second brain with AI: Obsidian, Notion and Claude
With AI, the game changes. Many people connect their Obsidian or Notion second brain to Claude or ChatGPT, have notes summarized, connections suggested, or ask questions about their own collection. That's a big step.
But the basic problem remains: the AI works on notes a human wrote. And after every session it forgets what it learned along the way.
The second brain that writes itself
Hebby turns the principle around. Instead of you maintaining your second brain, it grows on its own while you work with your AI agents. That solves exactly the three problems:
- It fills itself: Decisions, insights and experience from your sessions with Claude Code or Codex land in Hebby automatically. And like the brain during sleep, it tidies up on its own.
- It remembers by itself: Hebby brings the right knowledge into the session, without anyone having to search for it.
- It thinks along: A graph memory built in-house recognizes connections, and Hebby has ready what will be needed next.
A classic second brain is an archive. Hebby is a colleague with a memory.
Who benefits from an AI second brain
An AI second brain like Hebby is made for everyone who works with AI agents every day: developers with Claude Code or Codex, teams with many projects, freelancers who look after several clients. Anywhere knowledge emerges in conversation and would otherwise be lost.
You don't have to give up your note-based second brain for it. Hebby adds what it's missing: a memory that lives, learns and thinks along.
Hebby Memories: the second brain for Claude Code, Codex & co. Learns as you work, thinks ahead, never forgets what matters. Get Early Access →
Frequently asked questions
What is a second brain?
A second brain is a personal system outside your head where you collect and organize knowledge, ideas and project information. The term became famous through Tiago Forte's Building a Second Brain method.
Which app is best for a second brain?
Note apps like Obsidian, Notion or Logseq are popular. If you work with AI agents like Claude Code, you also benefit from an AI memory like Hebby that fills itself while you work.
Can Claude be a second brain?
On its own, Claude forgets after every session. Connected to an AI memory like Hebby, Claude Code becomes a second brain that remembers decisions, projects and experience, and brings them back automatically.