My Second Brain — Development skill for Claude Code

My Second Brain

**The one asset that stays yours no matter which AI model ships next quarter.**

A Claude Code skill that builds and runs a complete second brain for a business owner: one vault, two wings (your life in a personal wing, your business in a four-layer knowledge map), operated in plain conversation, with Obsidian as the viewing deck.

And it does the two things note systems never do: it **grows its own memory** (every AI conversation becomes searchable history, and what a working session taught is written down at its closeout, while whoever was in it still remembers; nothing is kept until you approve the exact words), and it **keeps machines on guard** (a read-only inspector that sweeps the vault, plus a safety lock that blocks the one delete you cannot undo). The rules are not just written down; they are enforced.

Install

npx skills add -g breakthrough-edu/my-second-brain

The `-g` is not optional here: without it the install lands in the current project folder, and this skill has to sit at the user level to find its own payload.

Then open Claude Code and say:

set up my second brain

Ten minutes later you are looking at the dashboard of your half-built brain.

Already running it? Updating to the latest version is one line, and it never touches your vault, only the skill files.

⚠️ **Read this before you update, if your vault was built before August 2026.** The vault's shape changed in that release: the business wing moved and gained an activity layer, folder doors changed name, and one frontmatter field was renamed. Because an update never touches your vault, **an older vault and a newer skill no longer describe the same house**, and the skill now notices instead of proceeding as though they matched. What that means in practice: it will tell you, in specifics, which parts differ; reading