CODEX
The vault — everything you collect, kept and taught back.
CODEX — WHAT AN AGENT DOES HERE
CODEX is the collector. Send it anything — a reel, a post, an image, a video, a link, a whole page — and it stores the thing, transcribes what is said in it, tags it, and files it where you will find it again. Over time that pile becomes your learning record: the agent sees what you keep reaching for, builds tutorials out of what you already know, and quizzes you on what you meant to learn. Underneath sits your own private vault — Nextcloud on your own machine, connected to the agents — so the collection belongs to you the way a bookshelf does.
- Capture anything: reels, posts, images, videos, links, pages — one message and it is kept
- Transcription of every video and voice note, so the words become searchable
- Automatic sorting and tagging — the vault stays tidy on its own
- A learning record: what you saved, what you practiced, what comes next
- Tutorial drafting — the agent turns your notes into something you can teach
- A private vault on Nextcloud — your files, your machine, your rules
Codex is two things: a learning assistant — one-on-one help with anything on this page — and the vault itself: a growing, private collection of everything worth keeping, connected to the internet's best free knowledge.
The digital library on this site holds the book collection. This page is the wider map — where to learn free at world-class quality, and the tools to make what you learn stay yours.
Build the vault
Three open-source pieces that turn 'saved somewhere' into 'findable forever'.
Nextcloud →
Your own private cloud — files, photos, notes, calendars — on hardware you control.
Karakeep →
The open-source bookmark-everything app: links, notes, images, with AI tagging built in.
Whisper →
Open speech-to-text that runs locally — the engine that makes every saved video searchable.
Free world-class courses
Real university material, free, no enrollment. Pick one and finish it.
MIT OpenCourseWare →
Real MIT courses — lectures, notes, exams — free.
Khan Academy →
Math and science from zero to university, patiently taught.
freeCodeCamp →
A complete programming education, free, with certificates.
Yale Open Courses →
Yale lectures and seminars, free, with reading lists.
Free books and texts
Five libraries that between them cover most of human writing. Pick a shelf, not a single book.
Internet Archive →
Millions of books, recordings, and websites, preserved and lendable.
Project Gutenberg →
70,000+ public-domain classics in every format.
Standard Ebooks →
Public-domain classics, beautifully typeset.
Open Library →
A card catalog for every book ever published — with borrowing.
LibriVox →
Free audiobooks of the classics, read by volunteers.
Interactive science labs
Learning that happens in your hands — run the experiment instead of reading about it.
PhET Simulations →
Hundreds of free physics, chemistry, and math simulations from the University of Colorado.
NOBOOK Chemistry →
A full virtual chemistry lab in the browser — mix, heat, and watch reactions safely.
Audio and podcasts
For when you're moving. Shows that teach at depth, not at attention.
Hardcore History (Dan Carlin) →
Long-form history with serious sourcing — six-hour episodes that earn the runtime.
Lex Fridman Podcast →
Three-hour interviews with the people actually doing the work — science, engineering, philosophy.
Sean Carroll's Mindscape →
Physics, philosophy, complexity — a working physicist explaining his own field.
Art, architecture, and 3D scans
When you want to look at something beautiful and understand why it's beautiful.
The Public Domain Review →
Curated wonders from the public domain, with essays.
Scan the World →
3D scans of the world's sculpture, free to download.
Smithsonian Open Access →
Millions of images and 3D models, free to reuse.
Wikimedia Commons →
The community media archive — 100M+ files, free to use with attribution.
Repos worth knowing
Where to look when you want the underlying source, not the article about it.
GitHub →
Where most open-source software lives. Search by topic, not just name.
ArXiv →
Pre-print papers in physics, math, CS, and biology — before peer review.
GitHub — awesome lists →
The 'awesome' curated lists — every field has one, maintained by the community.
Free programming books →
The Ebook Foundation's giant list of freely available programming books — every language, every level.