Big Brain MCP server

big-brain 🧠

One memory for every AI assistant you use: your notes, projects, and tasks, kept as plain markdown you own.

Each AI tool keeps its own private memory of you, and none of them share it. big-brain flips that around. Point it at a folder of markdown (a new vault, or the Obsidian vault you already have) and Claude Code, Claude Desktop, Cursor, Codex, or any other MCP client can search it, read it, capture into it, and keep your projects and tasks current. Switch models whenever you like; your context comes with you.

Replay of a real Claude Code conversation with a demo vault (transcript, recorded by scripts/demo-ai.mjs); timing is illustrative.

60-second start

npx @jzhao234/big-brain setup

That one command installs big-brain, creates a vault at ~/brain, connects Claude Code and Codex if you have them (MCP server plus the /brain, /capture, and /weekly skills), and prints the config to paste into Claude Desktop or Cursor. Pass a folder to use a different one, such as your Obsidian vault: npx @jzhao234/big-brain setup ~/Obsidian. It's safe to run again (anything already set up is left alone), and --dry-run shows the plan without changing anything.

Then restart your assistant and ask "what am I working on?" or "capture: call the dentist on Friday". Other clients, and browser chats like claude.ai and ChatGPT, are covered in Connect your AI tools.

Prefer to do it by hand? These three lines are what setup does for Claude Code:

npm install -g @jzhao234/big-brain
big-brain init ~/brain
claude mcp add --scope user big-brain -- big-brain-mcp --vault ~/brain

Already use Obsidian? big-brain reads an existing vault as is: no config file, no migration, and nothing is written until you ask for a change (setup writes nothing into it either). Add a brain.config.json later to map your folder names, one entry per folder (for example, "folders": {"projects": "Projects", "inbox": "Inbox"}), so projects and captures land where you keep them. See docs/vault-spec.md.

What you get

Shortened. The full README is on GitHub.