Twitter/X

Nick Spisak rebuilt Andrej Karpathy’s viral “second brain” in under 20 minutes…

Brief

Nick Spisak rebuilt Andrej Karpathy’s viral “second brain” in under 20 minutes (tweeted 2026-04-07), using a free Claude Code skill and npx skills add NicholasSpisak/second-brain. The workflow uses raw/, wiki/, and outputs/ folders plus Obsidian Web Clipper; an ingest command auto-generates wiki pages and mappings, supports expert-style queries, and includes a monthly lint to surface contradictions.

Source evidence

title: @NickSpisak_: we literally just rebuilt @karpathy's viral second brain in under 20 minutes.
...
author: @NickSpisak_
contenttype: tweet
publication: Twitter/X
published: 2026-04-07T16:31:00+00:00
source
url: https://x.com/NickSpisak_/status/2041554343137272071

word_count: 159

we literally just rebuilt @karpathy's viral second brain in under 20 minutes.
No code. One free Claude Code skill. Even if you've never opened a terminal.

Video

Corey Ganim (@coreyganim)

Karpathy dropped a viral post about building a "second brain" with AI. We built it live in under 20 minutes.

The system:
1. Three folders: raw/ (brain dump), wiki/ (AI organizes it), outputs/ (query results)
2. One-click install: npx skills add NicholasSpisak/second-brain
3. Obsidian Web Clipper to capture any article with one click
4. Run "ingest" and the AI reads everything in raw/, builds wiki pages, and maps connections automatically
5. Query your own knowledge base like talking to an expert
6. Monthly lint command catches contradictions and gaps before they compound

Day 1 it's basic. Day 90 it's a company asset nobody else has.

Free skill in the YouTube description that scaffolds the whole thing in 60 seconds.

Video below, YouTube link in the replies.

Video

— https://nitter.net/coreyganim/status/2041540491859169435#m