Give Your AI a Second Brain in 30 Seconds: Claude Plus Obsidian

Three steps

The short is a straight tutorial. Step one, install the Claude desktop app and open the Code tab. Step two, install Obsidian, which is free. Step three, paste one prompt. After that, Claude saves what matters about each project into notes, links them, and reads them first the next time you open the project. That is the whole trick: memory as files you can see, not a hidden setting.

Why a notes app

Obsidian looks like any other notes app, but a vault is a folder of Markdown on your machine. Claude Code can read and write files, so it can read and write your vault. You get a memory you can open, correct, or delete, and it works the same for any other local coding agent that can read files. Nothing is locked inside one vendor.

What the prompt sets up

The prompt asks Claude to check for Obsidian and any existing vaults before touching anything, then to ask what you want to remember and which tools you use. It creates a small hub: a start page, a working agreement with the rules, a checkpoint template, and a folder per project with an index, a checkpoint, and a decisions note. The rules are short. Read the checkpoint before starting. Update notes when something important changes. Leave a checkpoint before stopping. Save decisions and state, not chat logs, and never secrets.

Get the prompt

We said “comment BRAIN” in the video. You do not have to. The prompt, plus a ready-made skill for Claude Code and Codex, is public in Labstack on GitHub. Copy the install prompt from the README, paste it into your coding agent with a project open, and confirm the vault and folder when it asks. The longer companion video, Why Your Coding Agent Forgets Things, shows the same vault shared between Claude Code and Codex, so a task started in one agent can be picked up in the other.

Build the vault properly

Thirty seconds gets you connected. A second brain that stays useful for years takes more: one vault, a folder scheme you never think about again, links instead of tags, daily notes from a template, and a weekly pass that empties the inbox. We wrote the whole thing up, from the human side of the vault through every agent install route, the handoff, what to save, and how this relates to Obsidian’s own Second Brain plugin, in the Second Brain Guide.

Sources: the Labstack second-brain README and Obsidian’s download page.