Use cases · what a brain is for
Don’t search your data. Give your brain a goal.
A second brain built from your own data exports isn’t a filing cabinet — it’s a personal AI assistant with memory, a personal CRM that fills itself, a mirror that shows you what Facebook and Google know about you, and for teams, a company knowledge base your AI can use on day one. Every use case below names the exact prompt and the exact note in the vault that answers it — all of it 100% local, zero network calls, message text never read.
Personal · every day
A personal AI assistant that actually knows you.
ChatGPT, Claude and Gemini all ship memory now — and every one of them keeps it in its own cloud, starting from zero. Your exports already contain years of who you know, where you’ve been and what you care about. Built into a vault, they become the AI memory you own: local, portable across models, full on day one.
Your AI finally knows you
Read my brain, then answer like you've known me for ten years: what should I focus on this quarter?
Works with Claude Code, Codex & ObsidianNever walk into anything blind
Brief me before my meeting with Sam: our full history across every platform, and three openers that aren't small talk.
One merged note per person, every sourceYour network works for you
Who am I going quiet on that I shouldn't be? Show my dormant-but-strong relationships and draft a reconnect note in my voice.
The personal CRM you never have to maintainWhy nothing else does this: vendor memory starts empty and never leaves the vendor. A local AI assistant over your own vault starts full — from data the platforms are legally required to hand you.
Same model · different answer
Ask AI without a brain. Then ask it with yours.
The model isn’t the difference — the context is. Here is the same question, to the same AI, before and after it can read your vault.
Who should I reconnect with this month?
I don’t have access to information about your relationships or contact history. Could you tell me who your friends and colleagues are, when you last spoke, and which relationships matter most to you? Generally, experts suggest reaching out to people you haven’t spoken to in a while…
Who should I reconnect with this month?
Three stand out from your dormant-but-strong list Dashboard.md: Dana K. — strength 4/5, last contact Nov 2023, you worked together 2019–2021 and she just changed companies 10-people/dana-k.md · Sam P. — 5 years of WhatsApp rhythm, quiet for 8 months 10-people/sam-p.md · Alex R. — met at the 2019 accelerator, invests in your space now 90-synthesis/network-map.md. Drafts in your voice are ready for all three.
That’s the whole product. Same model, same question — the left one asks you to remember; the right one already knows, and shows its sources.
Personal · the mirror
See what the algorithms know about you.
Ever searched “what does Facebook know about me” or “what does Google know about me”? The answer is in the export they’re required to give you — ad interests, inferred traits, off-platform activity. The brain files it where you can finally read it.
facebook-export.zip ├── ads_information/ │ ├── advertisers_using_your_data… 712 companies │ └── ad_preferences.json ├── other_logged_information/ └── apps_and_websites_off_of_facebook/ unreadable on purpose
vault/my-brain/50-mirror/ ├── inferences.md what they think you are └── ad-profile.md segments & advertisers
What are the strangest things the platforms believe about me — and what did they get wrong?
50-mirror/inferences.md · the demo people screenshotPersonal · the big moments
Get hired — or funded — through people you already know.
A warm introduction beats a cold application every time; the hard part is remembering who you know. The brain cross-references your applications, your network and your history into referral paths — the networking CRM for job seekers and founders that builds itself from your own data.
Get hired
"Companies I’ve applied to or searched for where I already know someone — ranked by tie strength, with a drafted note each."
Referral paths first, cold applications last.
Get funded
"Map every path from my network to investors who back companies like mine, including second-degree intros."
Warm paths from data you already own.
And when it’s neither of those: 90-synthesis/network-map.md surfaces the strong relationships that went dormant — with a genuine, non-awkward reason to write to each one this week.
Personal · taste, recall, timeline
Your taste, your places, your life — one queryable graph.
Years of Spotify, YouTube, Maps, searches and check-ins add up to something no recommendation engine has: your actual taste and your actual history. Ask it anything — it’s your life timeline, and it answers.
Recommendations that actually know you
Grounded in your saved places, reviews and years of listening — not in ads or what’s trending.
Somewhere to eat Friday I’ll actually like — from my saved places and reviews, not from ads.
Where did I see that?
Find that thing I searched or saved about sleep and training — around when I started running.
Your life, mapped
Reconstruct my 2019: where I lived, traveled, what I listened to, who I talked to most.
Travel like a local — the local is you
The itinerary only your data can write: your saved spots, your people in the city, and the gaps worth filling.
Plan Rome from my own history: places I saved, people I know there, plus gaps worth filling.
Company · the Company Brain
The company knowledge base that starts full — from exports you already have.
Every AI knowledge management tool indexes live systems and assumes clean context exists. Your company’s real institutional knowledge is in the archives: Slack exports, Workspace directories, CRM dumps, decommissioned wikis, mail headers. One local build turns them into a brain — people, teams, deals and expertise, identity-resolved. Message text is never read.
Who knows this? Who owns this?
Who knows payments? Best person, their team and channel, one backup — and how warm my path to them is.
From roles, channels & authorship — not surveillanceMemory that survives turnover
Maria resigned this morning. Which accounts and deals did she own, who did she talk to most, and what should her successor do in week one?
Knowledge transfer when an employee leavesDay one, fully briefed
Draft my week-one onboarding plan: the 5 people to meet with why, the 3 channels to read first, the questions to ask each team.
Works for a new hire — or a new AI agentof enterprise GenAI pilots deliver no measurable P&L impact — MIT names the root cause the “learning gap”: AI with no memory of the business. Fill the brain first, from data you already own, and every agent you deploy inherits it. The full company story →
The honest limits
What it won’t do — said upfront.
It’s a snapshot, not a live feed
Sharp on history, blind to this week. Re-export and update in place with --refresh — your edits are kept, and the run is summarized in _UPDATE_REPORT.md.
Message text is never read
WhatsApp, Slack, email, tickets: relationship signal is who, how often, how recent — never the content. That’s the code, not a policy.
Thin where you were thin
The brain is as complete as the data you feed it. Barely used a platform? That slice will be thin — and it will say so.
FAQ
Questions people actually ask.
What is a second brain app, and how is this one different?
A second brain app is an external, searchable system for what you know — notes, people, ideas. Every second brain and personal knowledge management tool starts empty and asks you to feed it. Second Brain Link starts yours full: it builds the vault from years of your own data exports (LinkedIn, Google Takeout, Instagram, Facebook and 24 sources in all) in about a minute, locally.
How do I see what Facebook or Google actually knows about me?
Request your official export (Facebook: Accounts Center → Download your information; Google: takeout.google.com). Both include the advertising and inference data platforms hold on you. Second Brain Link turns those files into a readable "algorithmic mirror" — your ad interests, inferred traits, and off-platform activity — as plain notes on your own machine.
Can my AI assistant have memory of my life without sending my data to a cloud?
Yes. ChatGPT, Claude and Gemini all ship memory now, but each vendor’s memory starts empty and lives on their servers. Second Brain Link builds a local, portable memory layer from your own exports — plain Markdown any AI can read. The transform runs entirely on your machine with zero network calls, and message text is never read.
What is a Company Brain?
A structured, AI-readable knowledge base of your company: people, teams, accounts, deals, wiki knowledge and collaboration signal, resolved into one graph. Second Brain Link bootstraps it from exports your company already has — Slack, Google Workspace, LinkedIn Company, CRM, wikis, mail archives — so agents and new hires inherit institutional memory on day one.
How is this different from enterprise search tools like Glean or Microsoft 365 Copilot?
Those tools index live, connected systems in the cloud — and they assume clean context already exists. Second Brain Link fills the brain first, from the historical export archives they skip (including the context of people who already left), and it runs locally: your company’s brain never leaves your machines. The two approaches compose — we’re the cold-start layer, not another index.
Is my data uploaded anywhere?
No. The core transform makes zero network calls — verifiable in the open MIT-licensed source. Message text, email bodies and ticket prose are never read (relationship signal is who/how-often/how-recent only), and there is no account and no telemetry. Cloud sync exists only as an optional paid product.
What should I do with my LinkedIn data export or Google Takeout?
Don’t let it rot in your downloads folder. Drop the zip on Second Brain Link — CLI, Studio, or the Agent Skill in Claude Code / Codex — and it becomes a connected, private knowledge graph: your people, career, places, interests and voice, ready for any AI to reason over. See the Sources page for every supported export.
Your data already exists. It’s already yours.
Free & open source (MIT) · 100% local · from zips to a working brain in about a minute.