What is a second brain?
Trimtab Labs is Lorin Symington. Last updated 6 October 2026
What is a second brain?
A second brain helps the AI help you. Think of it as an API to your life. Frontier models might be brilliant and PhD-level, but if they don't know who you are, they can't really help you in the way you want. A second brain gives your agent that context, so you don't have to keep explaining yourself. All your projects live in one folder: your second brain. Orientation documents, a router and an index are hooked into context automatically, so your agent doesn't go searching and wandering. It knows where everything is, and provisions its own context efficiently. It's a lot more than file management, RAG or a vector database. It knows your projects, your goals and your roadmap. You can give it personalities, and tell it to wear different hats, each pulling in different context. And it's just markdown files, so you can use Claude Code, Codex, OpenClaw or Obsidian with it. No vendor lock-in: as the frontier moves, you move with it.
Why have one?
Context is the new IQ. Same models as everyone else. But vastly better performance and convenience due to automatic context management. Your uniqueness gets understood and augmented by an agent when you give it the right context. It reduces error rates, it reduces repetition, it saves time, and if you build it properly, it improves your weak areas. Once a second brain is working well, business automation follows much more smoothly.
Who is it for?
Anyone who wants a sense of ownership over their AI. One size does not fit all: a brain built for someone else won't fit your brain. You build yours from the ground up, so that it feels like home. The agent interviews you and grows the structure around what you actually put in, whether that is journals and writing, content and clips, client files and SOPs, or research.
What does Trimtab Labs offer?
The Second Brain Seed, free and open source (MIT licence): one prompt that grows into your own AI second brain. A community where members share expert prompts, and where the brain is updated and upgraded whenever models or harnesses change. And paid support and guidance: sessions to set a second brain up together, 1v1, 1v2 or 1v3, and help along the way. The foundation is open source. Our expertise will cost you.
Why is the Seed free?
Because the goal is a supportive community that is building and sharing capabilities, and spreading the word about open alternatives and why they are superior to the corpo-bots: Grok Bot, Muse, Dots and Instinct, among others. With your own second brain you get full control over your intelligence and data, no commercial conflicts of interest, and no export button needed. Everyone will have custom AI agents soon. Who will control yours?
How do I start?
Download the Seed from GitHub (github.com/Loringtonian/second-brain-seed), open the folder in an AI coding agent such as Claude Code, Codex or Cursor, and say “build my second brain.” The onboarding is an interview: what the brain is for, your work, your gaps, your voice, what to pull in, and how private to keep things. Then you feed it your history: old journal entries, notes, exports, chats, bookmarks, whatever you have.
How do I book a session?
Paid support and guidance is available. Book a session at loringtonian.github.io/links. To ask about the community, email [email protected].
Who owns the data?
You do. It is markdown files in a folder you control. There is no platform, no account and no lock-in, so no export button is needed. It runs on any agent setup, and when a better model comes out you move and your brain comes with you. Every item gets a privacy level, from public to sealed, and every note is tagged by who authored it, so you always know which words are yours.