Open Brain — Chrome Extension

Save and search your Open Brain second brain directly from your browser.

Features

• Save thoughts from any webpage (text + source URL auto-attached)
• Semantic search across all your thoughts (browser, Telegram, Slack, Claude)
• Auto-Capture — select text on a page, open the extension, it's pre-filled
• Right-click menu — save or search selected text without opening the popup
• Omnibox — type brain <query> in the address bar for instant search
• Related thoughts — after saving, see similar thoughts you captured before
• Source filter — filter search results by source (browser, Telegram, Slack, Claude)
• Click to copy — click any result to copy it to clipboard
• Delete thoughts — remove thoughts directly from search results
• Keyboard shortcut — Ctrl+Shift+B (or Cmd+Shift+B on Mac) to open

Quick Start

1. Download the extension

Option A — Git clone:

git clone https://github.com/konepone/open_brain_feature.git

Option B — Download ZIP:

1. Click the green Code button at the top of this page
2. Click Download ZIP
3. Unzip the folder somewhere on your computer

2. Install in Chrome

1. Open chrome://extensions/ in your browser
2. Enable Developer mode (toggle in the top right)
3. Click Load unpacked
4. Navigate to the chrome-extension/ folder inside the downloaded repo and select it
5. The Open Brain icon should now appear in your toolbar

3. Set up the backend

You need a running Open Brain Supabase project with:

• The thoughts table and match_thoughts function
• An OpenRouter API key (for embeddings + metadata extraction)

Deploy the brain-api Edge Function (included in supabase-function/):

# Set your secrets (one-time)
supabase secrets set OPENROUTER_API_KEY=your-openrouter-key --project-ref YOUR_PROJECT_REF
supabase secrets set BRAIN_API_KEY=$(openssl rand -hex 16) --project-ref YOUR_PROJECT_REF

# Deploy
supabase functions deploy brain-api --project-ref YOUR_PROJECT_REF --no-verify-jwt

Note down the BRAIN_API_KEY you generated — you'll need it in step 4.

4. Configure the extension

1. Click the Open Brain icon in your toolbar (or press Ctrl+Shift+B)
2. The settings panel opens automatically on first use
3. Enter:
   • API URL: https://YOUR_PROJECT_REF.supabase.co/functions/v1/brain-api
   • API Key: the BRAIN_API_KEY you generated above
4. Click Speichern (Save)

Usage

• Save: Type a thought and press Ctrl+Enter or click "Speichern"
• Search: Type a query in the search field and press Enter
• Right-click: Select text on any page → right-click → "Im Brain speichern" or "Im Brain suchen"
• Omnibox: Type brain in the address bar, press Tab, then type your query

Tech Stack

• Chrome Extension Manifest V3
• Supabase Edge Functions (Deno)
• pgvector for semantic search
• OpenRouter API (text-embedding-3-small + gpt-4o-mini)

License

MIT