# A second brain for your business > The second brain idea, applied to a whole team: one set of linked pages on workflows, systems, decisions and people that every staff member and AI agent reads and writes, owned by the business. - Canonical: https://sentrysolutions.ai/company-brain/second-brain-for-your-business # A second brain for your business. The second brain idea works for one person. This is what changes when a whole team, and every AI agent working for it, has to share one. [What changes for a team](#what-changes) [What is a company brain?](https://sentrysolutions.ai/company-brain/what-is-a-company-brain) The short answer A second brain for a business is one set of linked pages on how the business works, its workflows, systems, decisions and people, that every staff member and every AI agent reads before acting and writes back to as they work. Unlike a personal second brain, it has many writers, so it needs typed pages, an owner on each one, a daily check for pages that disagree, access by role, and ownership that stays with the business when people leave. We call it a company brain. ## Where the second brain idea comes from The phrase took off with Tiago Forte's book _Building a Second Brain_: capture what you learn in one trusted place so your head is free to think. Note apps like Obsidian and Notion became the usual home for it, with linked notes that grow into a personal map of what you know. Andrej Karpathy then pushed it towards AI with the idea of a personal LLM wiki: a structured, machine-readable folder of context about you that any model can read, so the model is useful to you specifically rather than to a generic user. We wrote about what that idea means for an organisation in [From Karpathy's LLM wiki to the company knowledge layer](https://sentrysolutions.ai/blog/karpathy-llm-wiki-for-organizations). Both versions are built for one person. A business is a different problem: many writers, many readers, and work that has to carry on when any one of them is away. ## One person's second brain against a team's The idea carries over. Almost everything about how it is written, read and owned does not. Personal second brain A team's company brain Who writes One person Everyone on the team, and every AI agent working for it Organised around How one person thinks How the work runs: workflows, systems, decisions, people When two notes disagree You know which one you meant Someone has to settle it, and the brain has to show who did Who can read what Just you Access by role, so finance pages are not open to everyone When someone leaves The notes leave with them What they knew stays, because it was written in as they worked Who owns it The person The business ## Four things that change for a team Sharing a notes vault with the whole company is a reasonable first step, and the notes are often good. These are the changes that turn shared notes into something a team and its agents can run on. ### Pages are about the work, not the topic A personal vault is usually notes by subject. A team brain is built from typed pages: a workflow page for each job, a system page for each tool, a decision page for each choice that was settled, a page for each person. That structure is what lets an agent find the one page it needs before it starts a job. ### Writing happens inside the work Personal second brains depend on the habit of capturing. A team cannot rely on everyone having that habit. In a team brain the agent that ran a job writes back what it learned before it finishes, and a correction from a person is written down as a rule, so the brain grows whether or not anyone remembers to take notes. ### Somebody settles the conflicts Two people will describe the same process two ways. A team brain needs a daily check that flags pages that have gone stale or contradict each other, and a named person who decides which one is current. That is the part a personal system never needs and a business cannot do without. ### Every model can read it The brain is plain linked pages, so Claude, ChatGPT, Copilot or Gemini can all read it over an open interface. Changing models changes nothing in the brain, which matters when the business, not an individual, is the one paying for and depending on it. How we would start ## Start from the work, not from the notes We do not begin a team brain by importing everyone's notes. We begin with the jobs the team does every week, write a workflow page for each, and connect the systems they run on. The brain then grows from the work people and agents do every day, which is why we build it as part of moving a team onto AI, set out in our [AI operating system](https://sentrysolutions.ai/ai-operating-system) methodology. We run [our own business on one](https://sentrysolutions.ai/company-brain/ours), and the [company brain page](https://sentrysolutions.ai/company-brain) explains how one gets built. ## Frequently asked questions ### What is a second brain for a business? It is the team version of a personal second brain: one set of linked pages on how the business works, its workflows, systems, decisions and people, that every person and every AI agent in the business reads and writes. We call it a company brain. ### Can we just share our Notion or Obsidian notes? You can share them, and they are a good starting point, but shared notes are not a team brain on their own. Personal notes are organised around how one person thinks. A business needs pages organised around how the work runs, with an owner on each page, a way to settle two pages that disagree, and access that does not walk out the door with one person. ### How is this different from Karpathy's LLM wiki idea? Andrej Karpathy's idea is a structured folder of context about one person that any model can read. A company brain applies the same idea to an organisation. The structure is the same kind of thing, plain linked pages a model can read, but it has to handle many writers, conflicting versions and permissions, which one person's wiki never does. ### Who owns a business second brain? The business does. It lives in plain files and links the business holds, readable by any model. When someone leaves, what they knew stays, because it was written into the brain as part of their work rather than kept in their own notes. ### Does every staff member have to keep notes? No. The point of a team brain is that people do not keep notes for it. When a person or an agent finishes a piece of work, what it learned is banked as a page or an edit, and a person approves anything that changes how the business runs. ### Is this only for large companies? No. Small teams feel the loss of knowledge sooner, because one person leaving takes a larger share of what the business knows. A team of five with a few dozen accurate workflow pages gets real value from one. Read next ## More on the company brain [ ### The company brain What one is made of, how one gets built, and what it is not. ](https://sentrysolutions.ai/company-brain)[ ### What is a company brain? The plain definition: linked pages on workflows, systems, decisions and people that every agent reads and writes, and why a wiki is not one. ](https://sentrysolutions.ai/company-brain/what-is-a-company-brain)[ ### Our company brain, live and growing Sentry AI runs its own business on its own brain. The page count, the departments, and how it grows. ](https://sentrysolutions.ai/company-brain/ours) ## Want a second brain your whole team can use? The free AI readiness check maps the tools your business already runs and shows which jobs a team brain would help first. 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