# Brotherhood

A relay-backed MCP server that lets two Claude Code sessions — on different computers — communicate in real time. Both sessions connect to a shared cloud relay via HTTPS POST and Server-Sent Events. Messages flow bidirectionally, enabling AI-to-AI collaboration across any network.

❯cat brotherhood/ARCHITECTURE.md

## How It Works

Each machine runs the Brotherhood MCP server locally (stdio). Both servers connect to a shared relay deployed on Vercel, authenticated by a room ID and secret. Machine A posts a message via HTTPS; the relay fans it out as an SSE event to Machine B — and vice versa. The relay holds nothing to disk; it is pure in-memory pub/sub with presence tracking.

Claude (Mac A) ──stdio──▶ Brotherhood MCP
                                └── HTTPS POST ──▶ Relay (Vercel)
                                                         └── SSE ──▶ Brotherhood MCP ──stdio──▶ Claude (Mac B)

❯brotherhood --demo

## Screenshots

brotherhood — Session A · Mac Mini

❯  send_message
   text: "Deploy feature/new-ui to staging, then run smoke tests"

   ✓  Message delivered to room: dev-sync-01
   ✓  Peer connected: Mac-Book-Pro.local

brotherhood — Session B · MacBook Pro

   ← Brotherhood: new message
   "Deploy feature/new-ui to staging, then run smoke tests"

   Processing...
   ✓  git push origin feature/new-ui
   ✓  Triggered CI pipeline #2847
   ✓  Smoke tests: 42/42 passed

❯  send_message
   text: "Done. Pipeline green, staging updated."

❯grep -n "## Features" brotherhood/README.md

## Features

+Real-time bidirectional messaging between Claude sessions
+Cloud relay with SSE + HTTPS POST transport
+Shared room pairing with secret key
+Zero persistence — in-memory pub/sub relay
+One-command Vercel deployment

❯brotherhood --compare

## vs. The Field

Feature	Brotherhood	Shared filesystem	Manual webhooks
Real-time delivery	✓	✗	✓
AI-to-AI native (MCP)	✓	✗	✗
Works across networks	✓	✗	✓
Zero-config pairing	✓	✗	✗
No persistent storage	✓	✓	✗

❯cd brotherhood && cat INSTALL.md

## Installation

Install the MCP server

Run on both machines — no build step required.

npx -y @web4w3/install brotherhood

Deploy the relay to Vercel

One-command deploy of the pub/sub relay. Free tier is sufficient.

cd relay
npx vercel --prod

⚠ Copy the relay URL from the Vercel output — you need it in the next step.

Set environment variables on both machines

Each machine needs the same room ID, secret, and relay URL.

export BROTHERHOOD_ROOM_ID=my-room
export BROTHERHOOD_SECRET=a-long-secret
export BROTHERHOOD_RELAY_URL=https://relay.vercel.app

Add to Claude Code on both machines

Both Claude sessions load the MCP server — they will find each other automatically.

{
  "mcpServers": {
    "brotherhood": {
      "command": "npx",
      "args": ["-y", "@web4w3/install", "brotherhood"],
      "env": {
        "BROTHERHOOD_ROOM_ID": "my-room",
        "BROTHERHOOD_SECRET": "a-long-secret",
        "BROTHERHOOD_RELAY_URL": "https://your-relay.vercel.app"
      }
    }
  }
}

❯cat brotherhood/package.json | jq '.dependencies | keys'

## Tech Stack

Node.jsTypeScriptSSEVercelMCP SDK

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