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.

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

# 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

Related Resources

• https://www.reddit.com/r/ClaudeAI/comments/1rv5ox0/
• Claude Code Official Documentation (CLAUDE.md Configuration)
• Obsidian Official Site