Focus Shield

The first site blocker with an AI bouncer.

Instead of blocking distracting sites outright, Focus Shield asks why you want to visit. Based on your reasoning it either blocks you or grants a specific duration, then re-blocks automatically. No manual timers. No workarounds. No willpower battles.

Install from the Chrome Web Store

The secret: typing your reason makes you self-aware

It is easy to lie to yourself clicking "just 5 more minutes." But when you have to type "check how many likes my post got" you suddenly realize: is this really what I need right now? The bouncer forces honest self-reflection before every distraction.

You type	You get
"Watch React tutorial"	✅ 15 minutes
"Check weather"	✅ 20 seconds
"Check colleague's LinkedIn profile"	⏰ Saved to To-Do Reminders instead
"Scroll X feed"	❌ Stay focused

Features

• AI bouncer. Type why you need the site. The model evaluates the reason in context, and can ask a follow-up question before deciding.
• Smart time-boxing. The AI picks the duration. Quick lookup gets 30 seconds, a tutorial gets 15 minutes. You never set a timer.
• Auto-reblock. When time expires every matching tab redirects back to the block page. A live countdown sits in the toolbar badge.
• To-Do Reminders. Found something interesting but not urgent? Save it in one click, GTD style, and check it on your break instead of during deep work. The AI suggests this on its own when something can wait.
• Strict Mode. Block everything except your allowed work sites.
• Access history. Recent attempts per site feed back into the prompt, so repeated vague reasons get more skepticism, not less.
• Distraction Mode. A 10 minute window where your saved reminder sites open freely.
• SiteBlock import, dark mode, and no analytics. Your sites, history, and reminders live in chrome.storage on your machine.

Everything lives on one settings page: your reminders, your lists, and an access history that shows what you tried to open and what the bouncer did about it.

How it works

client/    Chrome extension (React 19 + TS + Tailwind v4, Manifest V3)
  background/   service worker: tab interception, storage, alarms
  blocked/      the block page and its conversation UI
  options/      settings, history, reminders
server/    Deno API (the bouncer). Deployed on Deno Deploy.
dist/      build output, load this in Chrome

The service worker watches tab navigation, matches the hostname against your lists, and redirects to a local block page. That page sends your reason plus page metadata and recent access history to the Deno server, which prompts a model on Groq and returns { valid, seconds, message, followUpQuestion }. On approval the worker writes a temporary unblock and schedules a chrome.alarms re-block.

No API key ships in the extension. The request carries the blocked URL, the page title and description, your typed reason, and the recent attempts for that site, so the bouncer has enough context to spot a pattern.

Quick start

# 1. Build the extension
cd client && npm install && npm run build   # output goes to ../dist

# 2. Run the bouncer
cd ../server
echo 'GROQ_API_KEY="your-key"' > .env       # get one at console.groq.com
deno task dev                                # http://localhost:8000

# 3. Load in Chrome
# chrome://extensions -> Developer mode -> Load unpacked -> select dist/

A dev build (npm run dev) points at http://localhost:8000; a production build points at the deployed server.

Server configuration

Env var	Default	Purpose
GROQ_API_KEY	required	Groq API credentials
GROQ_MODEL	openai/gpt-oss-120b	Swap models without a code change. Groq retires models periodically, which shows up as every request failing at once.

Release

1. Bump version in client/manifest.json
2. cd client && npm run package writes focus-shield-v<version>.zip to the repo root
3. Upload it to the Chrome Web Store dashboard

Tech stack

Extension: TypeScript, React 19, Tailwind CSS v4, Vite, Manifest V3 service worker. Server: Deno, Groq (openai/gpt-oss-120b), Zod for structured output, CORS-enabled REST.