Workflows8 min read

How to build your AI second brain with Claude and Obsidian

The Karpathy method. A personal knowledge base that compounds every day, never forgets, and gets smarter the more you use it.

What you need

Just two tools. Obsidian is a free markdown editor, your window into the wiki with graph view, links, and fast search (obsidian.md). Claude Code is the AI agent that reads your vault, builds the wiki, and maintains everything (claude.ai/download).

Step 1: Create your vault

Download Obsidian, open it, and create a new vault. Name it whatever you want and put it on your desktop. This folder is where everything lives. Inside it, create exactly two folders:

raw-sources/ is your junk drawer. Articles, notes, screenshots, transcripts, bookmarks, ideas. Everything goes here, unorganized. These files are immutable. Claude reads them, never changes them.
wiki/ is where Claude writes the organized version. Summaries, concept pages, comparisons, an index. Claude owns this folder. You read it, Claude writes it, never edit it by hand.

Step 2: Add the schema file (the most important step)

Create a file in the vault root (not in any folder) called CLAUDE.md. This schema file tells Claude how the wiki is structured and what workflows to follow. It is what makes Claude a disciplined wiki maintainer instead of a generic chatbot. Open this link, select all, copy, and paste it into your CLAUDE.md:

https://gist.githubusercontent.com/karpathy/442a6bf555914893e9891c11519de94f/raw/llm-wiki.md

Step 3: Fill your raw sources

This is where most people stall. They make the folders and stare at an empty directory. Don't. Dump everything you already have: saved articles, call transcripts, meeting notes, research, podcast notes, video summaries, old project notes, screenshots.

No existing material? Open a Claude chat and talk for 20 minutes about your work, your goals, and what you're building. Save it as Memory.md and drop it in raw-sources/. That's enough to make your first session feel like Claude actually knows you.

Step 4: Tell Claude to build the wiki

Point Claude Code at your vault folder and run this, then walk away and let it work.

claude -p "Read everything in /raw-sources/. Compile a wiki in /wiki/ following
the rules in CLAUDE.md. Create an index.md first, then one .md file per major
topic. Link related topics using [[topic-name]] format. Summarize every source.
Log everything to log.md." --allowedTools Bash,Write,Read

When it's done you'll have a wiki full of organized articles, connections you didn't see, summaries of things you forgot you saved, and an index that makes everything searchable in seconds.

Step 5: Use it every day

Three operations you'll use on repeat. First, ingest new sources. Install the Obsidian Web Clipper extension, clip an article into raw-sources/, then tell Claude:

claude -p "I just added an article to /raw-sources/. Read it, extract the key ideas,
write a summary page to /wiki/, update index.md, and update any existing concept pages
this connects to. Log what you changed to log.md." --allowedTools Bash,Write,Read

Second, ask your wiki questions once it has 10 or more articles. What patterns keep showing up across my customer calls? What did I decide last time I hit this problem? Where are the gaps in my strategy? Third, run a weekly health check to catch contradictions, orphan pages, and outdated claims before they compound:

claude -p "Read every file in /wiki/. Find contradictions between pages, orphan pages
with no inbound links, concepts mentioned repeatedly with no dedicated page, and claims
that seem outdated based on newer files in /raw-sources/. Write a health report to
/wiki/lint-report.md with specific fixes." --allowedTools Bash,Write,Read

Step 6: Set up automations (optional but powerful)

Set a morning briefing up once and it runs every day. After any meeting, drop the transcript in raw-sources/ and have Claude extract every decision and action item, file the actions to an action tracker, log the decisions, and create a topic page linking back. Every decision filed, every action tracked, nothing lost to chat history again.

Tips and tricks

Obsidian Web Clipper converts any web article to markdown in one click. The fastest way to get sources in.
Graph View shows the shape of your wiki: which pages are hubs, which are orphans. Open it regularly.
Put your vault in a git repo. It's just markdown, so you get version history and backups for free.
Ingest one source at a time and stay involved. Read the summaries, guide what Claude emphasizes. Better results than batch-dumping everything.
Save good answers back. When Claude gives you a great synthesis, file it as a new wiki page so your thinking compounds like your sources.