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

Drop source material into raw/
Say "ingest this"
AI reads, extracts key ideas, creates/updates wiki pages
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.

[[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