I used Obsidian as a persistent brain for Claude Code and built a full open source tool over a weekend. happy to share the exact setup.

TL;DR Highlight

A development workflow sharing how someone used an Obsidian vault as Claude Code's persistent memory to ship an open-source tool in a weekend.

Who Should Read

Developers using Claude Code on long-term projects who need persistent context across sessions.

Core Mechanics

By treating an Obsidian vault as a structured knowledge base, the developer gave Claude Code persistent memory of project decisions, architecture choices, and context that normally resets between sessions.
The Obsidian vault structure (linked notes, tags, backlinks) maps well to how Claude Code consumes context — hierarchical and cross-referenced information is easier to navigate than flat documents.
The workflow: maintain notes in Obsidian during development, export relevant notes as context at the start of each Claude Code session, update notes after each session with decisions made.
The developer completed a weekend open-source project in roughly 12 hours of actual work, citing persistent context as the key factor in maintaining coherence across sessions.
The approach works best for projects with many interdependent design decisions — for simple scripts or one-off tasks, the overhead isn't worth it.

Evidence

The Reddit post included the actual Obsidian vault structure used, with example notes showing how architecture decisions were documented.
Commenters noted this is essentially a more structured version of maintaining a CLAUDE.md file, with Obsidian's linking features adding value for complex projects.
Several developers shared that they'd tried similar approaches with different note-taking tools (Notion, Roam) with similar results.

How to Apply

Create an Obsidian vault for your project with notes for: architecture overview, key decisions (and why they were made), current state, and next steps.
At the start of each Claude Code session, export the relevant notes to a context file and load it. The /memory command or CLAUDE.md can hold a pointer to the full vault.
After each session, update your Obsidian notes with decisions made and new context. This investment pays off as the project grows.
Use Obsidian's linking features to create a decision log — link related decisions together so you can feed Claude Code a coherent narrative of the project's evolution.

Code Example

snippet

# CLAUDE.md Template Example
## Project Overview
- Stack: Next.js 14, TypeScript, Drizzle, Turso
- Deployment: Vercel

## Coding Rules
- Components are always functional
- API routes go under /app/api/

## Memory Files
- Detailed context: ./obsidian-vault/context.md
- Work logs: ./obsidian-vault/logs/

Terminology

ObsidianA local-first note-taking app that uses markdown files and supports bidirectional linking between notes — popular with developers for knowledge management.

Persistent MemoryContext or information that persists across Claude Code sessions, rather than resetting with each new conversation.

CLAUDE.mdA project-level markdown file that Claude Code automatically reads as persistent context for every session.