2024-01
LeetFox
A Chrome extension that coaches you through DSA problems in real time. Detects which LeetCode problem you're on, tracks your thinking, and gives Socratic hints — never just the answer.
Chrome ExtensionManifest V3Anthropic APINotion
Overview
LeetFox sits quietly in your browser while you grind LeetCode. It knows what problem you're on, watches your approach unfold, and steps in with a Socratic nudge when you've been stuck for too long — never giving away the answer.
Features
- Problem detection: Automatically identifies the current problem via the DOM
- Hint progression: Three levels of hints, each revealing a bit more, triggered by time stuck or manual request
- Session logging: Pushes a structured summary to Notion after each solved problem (time taken, hints used, approach)
- Streak tracking: Lightweight local streak counter with weekly goal setting
Stack
- Extension: Manifest V3 service worker + content scripts
- AI: Claude Haiku for fast, cheap hint generation
- Storage: Notion API for session logs, chrome.storage for local state
- UI: Vanilla TS + minimal CSS (no framework — keeps the bundle tiny)
Design decisions
Keeping the extension lightweight was a hard constraint. The content script is under 5 KB; all heavy lifting happens in the service worker or on the Claude API side.