Ai Second Brain

AI Second Brain

A Claude Code skill that walks you through building a living, searchable, AI-powered knowledge base from your own ChatGPT and Claude history, your raw research, and your daily inputs.

On 3rd April 2026, [Andrej Karpathy](https://github.com/karpathy) published a 1,500-word gist describing how to build a personal wiki using a folder of markdown and an LLM. Within 48 hours the X thread about it hit **16 million views**.

This skill packages Karpathy's idea — plus an AI-history organiser by [Alex Freedman](https://instagram.com/alex2learn) and the slash-command workflow shared by [Greg Isenberg](https://www.youtube.com/@GregIsenberg) — into a single Claude Code skill that walks any user through the full setup.

Built for non-technical readers of [MarTech AI](https://charliehills.substack.com).

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Install

The reliable way (works on every Mac, easy to update later):

git clone https://github.com/charlie947/ai-second-brain.git ~/.claude/skills/ai-second-brain

If `~/.claude/skills/ai-second-brain` already exists, back it up first:

mv ~/.claude/skills/ai-second-brain ~/.claude/skills/ai-second-brain.backup

Then open Claude Code in any folder and say:

Set up my AI second brain.

To update later:

cd ~/.claude/skills/ai-second-brain && git pull

Verify it installed

In Claude Code, type:

/skills

You should see `ai-second-brain` in the list. If you don't, the folder is in the wrong place — re-run the clone command and double-check the destination path.

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What it does

flowchart LR
    A[Your ChatGPT
& Claude exports] --> B[Step 1
AI Brain]
    C[PDFs, articles,
transcripts] --> D[Step 2
Karpathy Wiki]
    E[Gmail, Granola,
NotebookLM] --> F[Step 3
Living Wiki]
    B --> G[Tagged, linked
Obsidian vault]
    D --> G
    F --> G
    G --> H[Talk to it from
your phone via iMessage]

The skill walks you through three stages. You can do all three