---
title: Second Brain Vault
tags: [concept, system]
created: 2026-06-21
updated: 2026-06-21
source: https://x.com/ridark_eth/status/2068753952850546985
---
# Second Brain Vault
An Obsidian vault at `~/second-brain/` that serves as a persistent, queryable knowledge base. The AI ingests content, extracts key ideas, and creates wikilinked Markdown pages that compound over time.
## Concept
Inspired by Andrej Karpathy's 16M-view post: stop using AI to write code, use it to build a second brain. Point an AI at a folder, feed it content, and have it build a living wiki.
## Architecture
- **raw/** — incoming source material
- **wiki/** — generated wiki pages with [[wikilinks]]
- **inbox/** — quick capture for fleeting thoughts
- **_templates/** — note templates for consistency
## How It Works
1. Drop source material into `raw/`
2. Say "ingest this"
3. AI reads, extracts key ideas, creates/updates wiki pages
4. Ask questions across everything — forever
## Key Insight
The compounding mechanism is [[wikilinks]] — each new page links to existing pages, creating a navigable graph of knowledge. The more you feed it, the richer the connections become.
## Caveats
- **Pruning is mandatory.** A knowledge base you never weed becomes a junk drawer. Stale notes, contradictions, and dead links accumulate fast.
- **Ingestion is easy, maintenance is hard.** The real work is keeping the signal-to-noise ratio high.
## Related
- [[Graph Memory]] — structured entities/relationships in SQLite
- [[Hermes Memory]] — hot/warm/cold tiered text memory
- [[Obsidian]] — the note-taking app that renders this vault
## Source
From: [Karpathy's second brain post](https://x.com/ridark_eth/status/2068753952850546985)