Brain Personal OS Skill

The Brain personal OS skill is a free Claude skill that turns your Brain vault into a working system. Every piece of information gets one home, every session with Claude starts with your context loaded, and every session ends with a short daily log. The vault lives on your own MCP Self-hosted server, so the same system is there in every client you connect to it.

What does the Brain personal OS skill set up?

On first use it runs in setup mode. Claude interviews you briefly about your work and your role, and then creates a clean structure:

• Context: your profile and the rules Claude follows.
• Projects: one note or folder per project.
• Daily: one log per working day.
• Intelligence: decisions, insights and things you learned.
• Resources: reference material and links.

Each top-level folder gets a short description. Brain shows those descriptions in the root overview, so Claude knows where things belong without opening every folder. Claude also writes routing rules: which kind of information goes where.

How does the Brain personal OS skill run day to day?

After setup it switches to operate mode. At the start of a session Claude quietly reads your profile and the latest daily note, so you never have to explain again what you were doing yesterday. During the session, new information goes to the note where it belongs. If a note on the subject exists, Claude updates it instead of creating a second one.

At the end of the session Claude appends a short log to today’s daily note: what was done, what was decided and what comes next. When you correct Claude, for example “always write dates as YYYY-MM-DD”, the skill turns that correction into a permanent rule in your Context folder.

Which Brain tools does the Brain personal OS skill use?

Nine tools from the Brain MCP add-on:

• brain_list and brain_read to find and open notes.
• brain_search, which searches the index of summaries and headings first and falls back to a full scan, with up to 20 results.
• brain_write and brain_append. Append adds a dated separator before the new text, which suits a daily log.
• brain_move to put a note in the right folder.
• brain_describe_folder for the folder descriptions of up to 200 characters.
• brain_reindex to rebuild the search index after files changed outside the tools.
• brain_history to see recent changes when versioning is on.

The skill does not use brain_delete. Removing notes stays your call.

Does the Brain personal OS skill need Can make changes?

Yes. It writes, appends and moves notes all the time, so it needs Can make changes. That is the default for the Brain tool, unlike the other add-ons, which start read-only. You can check or change the mode per seat in My Account → MCP Self-hosted → Seats.

We recommend VERSIONING_ENABLED=true. Then every write is a git commit, and a note Claude rewrote by mistake is one step back in the history, not a loss. The logs folder in the vault is protected: Claude reads it but never writes there.

Can you open the vault in other tools?

Yes. The vault is a folder of plain markdown files on your server, set with VAULT_PATH. The skill writes notes with frontmatter, wikilinks and callouts, so the folder opens cleanly in Obsidian or any markdown editor. If you edit files there, ask Claude to run a reindex so search picks up your changes.

On the client side, the system works in Claude Desktop, Claude Code and any MCP client that supports Streamable HTTP or SSE. Your context is in the vault, not in one chat app.

What do you need for the Brain personal OS skill?

MCP Self-hosted and the Brain add-on. MCP Self-hosted costs € 217,80 excl. VAT: € 180,00/yr including 3 seats, and the Brain add-on is € 72,60 excl. VAT: € 60,00 per year. The skill is a free download without a license. The Brain MCP setup guide covers the vault folder:

VAULT_PATH=/vault
VERSIONING_ENABLED=true

How do you install the Brain personal OS skill?

1. Download it from this page. Checkout is free, and the zip appears under Skills in My Account.
2. Claude Code: unzip into ~/.claude/skills/, so it is active in every project.
3. Claude Desktop: add the zip in Claude’s skills settings.
4. Start with: “Set up my personal OS in Brain.” After that, just work; the skill loads your context itself.

On an existing vault with its own structure, tell Claude which folders to keep before you run setup mode.

The Brain personal OS skill is free. Download it here, browse the Claude skills catalog, or read the free Claude skills overview to see how skills and add-ons work together.