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shipped 2026

Second Brain

An Obsidian vault on iCloud: every note, every chat, every book, in one place I can talk to.

Second Brain hero
The vault as a graph: the dense core is the synthesized wiki layer, the orbiting points are raw notes, chats, books, and clips.

Why this exists

I’ve always written notes on my phone whenever I get a new idea. Not long ago I heard about someone using AI to help inspire new projects from a second brain; that alone convinced me it was worth building.

The whole pitch is: dump everything in, do almost nothing to maintain it, and have it there when you need it.

What it does

The vault holds four kinds of source material, all in plain markdown:

A wiki/ layer sits on top: synthesized concept and people pages built from the raw notes by a /process-inbox slash command. Sensitive material (credentials, PII) gets quarantined into a separate folder during processing so it never lands in the wiki.

How it works

The whole thing is plain markdown files on iCloud: no database, no proprietary format.

  1. Capture: Every new note lands in 00-Inbox/. Phone, PC, web clipper, and the import scripts all write there
  2. Sync: iCloud handles file-level sync between Windows and iPhone, no extra service in the middle
  3. Process: A /process-inbox command in Claude Code reads the inbox, synthesizes a wiki page (or extends an existing one), and quarantines anything sensitive
  4. Query: Obsidian’s full-text search handles everyday lookup. Claude Code is the chat with your brain interface; it can read the entire vault as plain markdown and reason across notes, chats, and books at once

One choice that mattered: keeping the AI out of band. Claude doesn’t run on every read; it runs when I run a slash command, on data I see before it lands.

What’s next

What I learned

I have a lot of chats with AI models. Watching them all pile up in one place has made me more aware of my own behaviors around reading and writing, including the fact that most of my own notes are 1–2 sentence scribbles (AI use isn’t helping with this). It’s nudging me toward longer-form writing.

Status

Shipped. Notes flow in daily, the wiki layer grows when I run /process-inbox, and Claude Code in the vault is now my default way to talk to my brain.

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