Second Brain

One shared memory for Claude, ChatGPT, Cursor, Codex, and every other AI tool you use.

You use Claude for some things, ChatGPT for others, and Cursor for code. But your context, including your projects, decisions, and preferences, does not move with you. You end up explaining yourself again and again.

Second Brain gives every AI tool access to the same persistent memory.

Unlike memory built into a single app, this memory belongs to you. It runs in your own Cloudflare account, stays under your control, and cannot be locked inside one AI platform.

Deploying takes about two minutes. See the Quick Start for the required configuration values.

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See it in action

How it works

Connect Second Brain to the AI tools you already use, then save information as it comes up.

Second Brain retrieves memories by meaning rather than exact wording. Asking:

What did I decide about the pricing model?

can surface the correct memory even when the original note used completely different words.

Memory tools

Save from anywhere

Memory is most useful when capturing information is easy. Second Brain connects to the tools and moments where context already exists.

• AI clients: Use remember directly within Claude, ChatGPT, Cursor, Codex, and other MCP clients.

• Command line: Run brain remember, brain recall, and other commands from your terminal.

  copy

  npm install -g second-brain-cf-cli
  

• Obsidian: Automatically sync notes using the Second Brain Sync plugin, also available through Obsidian Community Plugins.

• Browser extension: Capture a page or highlighted text using the Chrome extension.

• iPhone and iPad: Use the Brain Dump, Text Brain Dump, and Save to Brain shortcuts in integrations/ios-shortcuts/.

• Bookmarklet: Use the lightweight bookmarklet in integrations/bookmarklet.js.

Quick Start

Set up your Second Brain in three steps.

1. Choose an authentication token

Your AUTH_TOKEN is the password used to access your Second Brain.

Use either:

• A memorable phrase, such as coffee-lover-2026

• A randomly generated token:

  copy

  openssl rand -base64 32
  

Save this token somewhere secure. You will need it when authorizing clients and testing your deployment.

2. Deploy to Cloudflare

Click Deploy to Cloudflare and follow the prompts.

Enter the following value during setup:

Cloudflare will provision the required resources and deploy your Worker automatically. The Vectorize index is created for you during deployment with the correct settings (384 dimensions, cosine metric), so there is nothing else to fill in.

When deployment finishes, copy your Worker URL. It will look similar to:

https://your-worker-name.your-subdomain.workers.dev

3. Connect your AI clients

Choose the instructions for the clients you use.

Claude Code or Codex CLI

Run the command for your operating system, replacing YOUR-WORKER-URL with the Worker URL from step 2.

macOS, Linux, WSL, or Git Bash

curl -fsSL https://raw.githubusercontent.com/rahilp/second-brain-cloudflare/main/scripts/connect-ai-clients.sh | bash -s -- https://YOUR-WORKER-URL

Windows PowerShell

iex "& { $(irm https://raw.githubusercontent.com/rahilp/second-brain-cloudflare/main/scripts/connect-ai-clients.ps1) } -WorkerUrl https://YOUR-WORKER-URL"

The setup script configures the MCP connection and global instructions using OAuth. Your authentication token is not passed to the script.

ChatGPT or Claude desktop and web apps

These clients require two manual setup steps:

1. Add the provided custom instructions to the app's personalization settings.

2. Add the following URL as a custom MCP connector:

   copy

   https://YOUR-WORKER-URL/mcp
   

Follow the client-specific instructions in the wiki for the exact menus and settings.

Your Second Brain is now ready to use across every connected client.

Optional: Verify the deployment

Replace YOUR-WORKER-URL and YOUR-TOKEN with your own values:

curl -X POST https://YOUR-WORKER-URL/capture \
  -H "Authorization: Bearer YOUR-TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"content":"second brain is working","source":"test"}'

A successful response will look like:

{"ok":true,"id":"..."}

https://YOUR-WORKER-URL/mcp

claude mcp add --transport http second-brain https://YOUR-WORKER-URL/mcp

codex mcp add second-brain --url https://YOUR-WORKER-URL/mcp

Authorization: Bearer YOUR-AUTH-TOKEN

npm install
npm run deploy

Documentation

• Setup Guide: Deploy the Worker, configure authentication, and connect AI clients
• How It Works: Semantic search, chunking, memory classification, and duplicate detection
• Connect to AI Clients: ChatGPT, Claude, Claude Code, Codex, and other MCP clients
• Capture from Anywhere: Browser extension, bookmarklet, iOS Shortcuts, and share sheet
• Web UI: Dashboard and mobile interface
• Obsidian Plugin: Installation, configuration, and sync modes
• API Reference: REST and MCP endpoints

Technology

Second Brain is built with:

• Cloudflare Workers
• D1 SQLite
• Cloudflare Vectorize
• Workers AI
• Cloudflare KV
• Model Context Protocol
• TypeScript

It runs within Cloudflare's free tier at personal scale.

Your data stays in your own Cloudflare account.

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