Drop in your lecture notes or PDFs and Cortex builds the whole study system for you — a day-by-day plan, flashcards on spaced repetition, and surprise active-recall quizzes that make it stick.
Free & open source · Apple Silicon · Everything stays on your Mac
What it does
Cortex uses Claude to turn raw material into everything the learning-science literature says actually works — then schedules it so you don't have to think about it.
Paste notes or upload .txt / .md / .pdf files. Claude reads everything and builds a day-by-day plan spanning study, review, recall, and practice.
Each plan comes with flashcard decks built from your material, reviewed on a spaced-repetition schedule. Or generate a deck from any note in one click.
Short-answer questions you answer from memory before revealing. Hits stretch the interval, misses come back in 30 minutes.
Cortex pings you at random moments with a question from your plans — cold recall, when you least expect it. Set the frequency and quiet hours.
A clean markdown editor for capturing lectures and readings — with tasks, study sessions, and a dashboard tracking it all.
No cloud, no accounts on someone else's server. Your notes and progress live in a local database in your Mac's app data. Full stop.
Cortex's AI features run through the Claude Code CLI on your machine, signed into your own Claude account — no API keys to manage and nothing extra to pay if you already have a Claude subscription. Notes, flashcards, tasks, and recall practice all work without it; you only need Claude for generating plans and decks. For personal use with your own account.
Install
Grab Cortex.dmg, open it, and drag Cortex into Applications.
The first time only: right-click the app and choose Open. Cortex is a free indie app and isn't notarized by Apple, so macOS shows a warning on double-click. If macOS still blocks it, approve it under System Settings → Privacy & Security → “Open Anyway”.
For the AI features, install Claude Code
(npm i -g @anthropic-ai/claude-code), run claude once, and log in.
Cortex picks it up automatically.
FAQ
Cortex isn't signed with an Apple Developer certificate (that's a $99/year program), so Gatekeeper can't verify it. The app is open source — you can read every line on GitHub or build it yourself. Right-click → Open bypasses the warning once; after that it opens normally.
Yes. Cortex has no server. Your account, notes, flashcards, and progress live in a local SQLite database on your Mac. When you generate a plan, your material is sent to Claude through your own Claude sign-in — the same as if you pasted it into Claude yourself — and nowhere else.
Only for the AI features (generating study plans and flashcard decks). Everything else — notes, manually-created flashcards with spaced repetition, tasks, sessions, recall practice on existing questions — works without it. AI features use your own Claude account via the Claude Code CLI, for your personal use.
Apple Silicon Macs (M1 and later) running a recent version of macOS. There's no Intel build at the moment.
Every study plan generates a bank of short-answer questions. Cortex schedules random notifications (you set roughly how often, and quiet hours) that ask one cold. Click the notification, answer from memory, self-grade — the schedule adapts like spaced repetition. Closing the window keeps Cortex running in the background so quizzes keep coming; press ⌘Q to quit fully.