Second Brain Bridge MCP server

🧠 SecondBrainBridge

Your Obsidian vault, searchable and reasoned over — inside ChatGPT, from your own Mac.

SecondBrainBridge is a Model Context Protocol (MCP) connector that lets ChatGPT search and reason over your Obsidian-style Markdown vault — a folder of notes on your Mac. It never uploads your notes to a third party — every action runs on your own Mac through a tiny local agent. The cloud piece is only a stateless relay that shuttles requests between ChatGPT and your Mac.

ChatGPT  ──OAuth──►  SecondBrainBridge relay  ──job queue──►  second-brain-agent  ──►  Obsidian vault
 (connector)          (Vercel, stateless)      (your Mac, polls & executes)      (Markdown notes on your Mac)

Your Mac is the only place your notes are ever read or written. The relay stores only short-lived job payloads and your account record; it never sees note content unless a job is in flight, and jobs expire in seconds.

For users — 3 steps

1. Create your account at secondbrainbridge.vercel.app and generate a pairing code.

2. Install the Mac agent (needs Node 18+):

npx second-brain-agent pair <YOUR-CODE>   # link this Mac to your account
npx second-brain-agent install            # keep it running on every restart

Point it at your vault folder — set SECONDBRAINVAULT=/path/to/your/vault, or save the path in ~/.secondbrainbridge-agent.json. The first time the agent reads a vault kept in a protected location (Documents, Desktop, or iCloud Drive), macOS asks once for Files-and-Folders access — click OK**.

3. Connect ChatGPT: Settings → Plugins → turn on Developer mode (Security & login) → Create a custom plugin → paste the MCP Server URL https://secondbrainbridge.vercel.app/mcp → Authentication OAuth → sign in & Allow.

That's it. In a new chat: "Search my notes for the Q3 planning doc" or "What did I decide about Project Atlas?"

Your Mac must be awake with the agent running. npx second-brain-agent install makes it start automatically at login and restart if it ever crashes.

Managing the agent

npx second-brain-agent status      # is it paired & reachable?
npx second-brain-agent logs        # recent activity
npx second-brain-agent uninstall   # stop auto-start

What ChatGPT can do

Retrieval is v1 ranked keyword + title match, so answers stay grounded in the passages that actually appear in your notes. (Semantic/cloud ranking is a Pro/cloud enhancement.)

Plans

SecondBrainBridge is free to start. Upgrade to Pro when you want the full graph and write access.

Shortened. The full README is on GitHub.