Your File System Is Already a Graph Database

The pitch

It has been reported that Andrej Karpathy recently floated a simple, tempting idea: use LLMs to compile your raw notes into an interlinked markdown wiki and treat Obsidian as your personal knowledge layer. A follow-up “idea file” for agents supposedly makes the setup easy. On the heels of that, a rumproarious post argues he’s been doing exactly this for years — allegedly hoarding 52,447 markdown files in an Obsidian vault — and that the humble filesystem itself is already a graph database. Files are nodes, wikilinks are edges, folders give you schema. No fancy vector store, no standalone graph DB, no RAG pipeline. Just files on disk.

How it works, in plain English

The system borrows PARA and Tiago Forte’s “second brain” ideas for organization — projects, areas, people, daily notes — then leans on an agent to stitch new inputs into place. After meetings, the agent drops a note into daily/YYYY/MM/DD, pulls attachments like Google Docs into markdown, and wikilinks conversations to people and projects. Over time each person’s note becomes a timeline; each project folder becomes the canonical history. The payoff? You point an agent at a starting document and tell it to “spider” the available sources; it assembles context and drafts design docs that don’t sound like they were written cold.

Why it matters

This isn’t just nerdy tinkering. The real argument here is that you’re doing context engineering — building the exact input an LLM needs to produce useful work. That changes the game for handoffs, onboarding, postmortems, even product strategy. Feels good, right? The practical risks remain: permissions, tooling for reliable syncing, and whether teams want their single source of truth scattered across personal vaults. But for individuals and small teams who already live in markdown and Obsidian, the promise is immediate: a searchable, link-first brain that remembers what you can’t.

The takeaway

Call it clever reuse or DIY graph engineering. Either way, it’s a reminder that sometimes the best infrastructure is the one you already have — if you just connect the dots.

Sources: rumproarious.com, Hacker News