/ai-second-brain

name: ai-second-brain
description: Walks the user through Charlie Hills's AI Second Brain + Karpathy Wiki setup from the MarTech AI newsletter. Use whenever the user mentions building an AI second brain, the Karpathy wiki, organising their ChatGPT/Claude exports in Obsidian, setting up a living wiki with Claude Code, connecting iMessage Channels, or installing the /today, /ideas, /create slash commands. Trigger on phrases like "set up my second brain", "build the Karpathy wiki", "follow Charlie's newsletter setup", "organise my AI conversations", "Obsidian + Claude Code setup", "I exported my ChatGPT data what now", or any reference to MarTech AI's Karpathy Wiki issue. Use even if the user only mentions one of the three steps (AI Brain, Karpathy Wiki, or Channels + slash commands).

AI Second Brain Setup

This skill walks the user through the full setup from Charlie Hills's MarTech AI newsletter issue *"How to build a second brain with Obsidian and Claude Code"*. The process turns a folder of exports and raw research into a living wiki the user can talk to from their phone.

The setup has three steps. The user can do all three or pick one — confirm at the start which they want.

1. **AI Brain** — export ChatGPT and Claude history, organise it in Obsidian as tagged, linked markdown 2. **Karpathy Wiki** — set up `raw/` and `wiki/` folders with Karpathy's `CLAUDE.md` instruction file so Claude Code can compile a living wiki from raw research 3. **Living Wiki** — add MCP connectors (Gmail, NotebookLM, Granola), set up iMessage Channels, scaffold the `/today`, `/ideas`, `/create` slash commands

How to use this skill

The user is most likely a non-technical newsletter reader. Many will be opening Terminal for the first time. Default to plain English, never assume CLI familiarity, and explain what each command does *before* running it.

The skill orchestrates a conversation. At each step there are things Claude Code can do (create folders, download files, install other skills, scaffold commands) and things only the user can do (request a data export from OpenAI, grant Full Disk Access in macOS System Settings, log in to NotebookLM in a browser). Be explicit about which is which. Pause and wait when the ball is in the user's court.

If the user says "skip step 1, I've already done it" or "just do step 3", honour that. Confirm what's already in place, then jump in.

Step 0: Pre-flight check

Before touching anything, confirm what the user has installed. Ask:

> Quick check before we start. Do you have: > 1. **Claude Code** installed and working? (you're using it now if so) > 2. **Obsidian** downloaded? (free from obsidian.md) > 3. Any **ChatGPT or Claude data exports** already requested? (the OpenAI one takes 1–3 days, so we may need to start it now and come back)

If Obsidian isn't installed, point them to https://obsidian.md and pause until it's done. If they haven't requested the ChatGPT export, kick that off **first** (instructions in Step 1) so it's processing in the background while they do the rest.

Also confirm where they want the brain to live. Default: `~/Desktop/Brain` (one word, no spaces — spaces caused issues for Charlie when he used "LLM Brain"). Use `Brain` unless the user pushes back.

Step 1: Build the AI Brain

The goal here is to turn years of ChatGPT and Claude conversations into a tagged, linked, searchable Obsidian vault.

1a. Request the data exports (user does this)

This is user-only. Walk them through both:

**ChatGPT** (do this FIRST — it can take up to 3 days): > Go to chatgpt.com → click your profile icon (top right) → Settings → Data Controls → "Export data". OpenAI will email you a download link. Tell me when you've requested it.

**Claude** (arrives in ~5 minutes): > Go to claude.ai → click your profile icon (bottom left) → Settings → Privacy → "Export Data". The email arrives in about 5 minutes. Tell me when you've got both ZIP files downloaded and unzipped.

Wait for the user to confirm. If they say "the ChatGPT one will take days, what do I do meanwhile" — suggest moving to Step 2 (Karpathy Wiki) since it doesn't depend on the exports.

1b. Set up the vault (Claude Code can do this)

Once the user has unzipped both export folders on their desktop, do this:

mkdir -p ~/Desktop/Brain

Then ask the user to drag the two unzipped export folders into `~/Desktop/Brain`. After they confirm:

ls ~/Desktop/Brain

Verify both folders are there.

Then tell them: > Open Obsidian. Click "**Open folder as vault**" (not "Create new vault"). Navigate to your Desktop and select the `Brain` folder. Tell me once it's open.

1c. Organise everything (Claude Code does this — this is the magic)

Once the vault is open in Obsidian, the user needs to launch a fresh Claude Code session pointing at the Brain folder. Tell them:

> Open a new Terminal window (Cmd+Space, type Terminal, hit Enter). Then paste this: > ``` > cd ~/Desktop/Brain > claude > ``` > Once Claude Code is running in that window, paste this prompt: > ``` > Organise this folder into an Obsidian vault. Convert all my ChatGPT and Claude conversations into individual markdown files with proper frontmatter (title, date, tags, category). Then launch 10 sub-agents to go through every conversation and smartly tag things: names, people, places, recurring themes, projects, and topics. Link everything together with wikilinks so the Obsidian graph connects related conversations. > ```

This will run for several minutes and spawn 10 sub-agents in parallel. When it's done, tell the user: > Open Obsidian. Hit **Cmd+G** (or Ctrl+G on Windows) to open Graph View. Every conversation is now a tagged, linked markdown file. Have a wander.

Step 2: Set up the Karpathy Wiki

The AI Brain organises the past. The Karpathy Wiki is a *living* knowledge base that grows every time the user drops in new research. The user dumps raw sources into a `raw/` folder, and Claude Code compiles struc