Sentient OS: The Open-Source AI That Learns Your Life Overnight
What Is Sentient OS?
What if your Mac studied your life while you slept — and woke up knowing exactly what you need? That’s the bet behind Sentient OS, a new open-source AI app from a Y Combinator Fall 2026 startup that turns your Mac into a computer that actually remembers you.
Here’s the core idea, and it’s a clever one. You connect the sources you choose — Apple Mail, Calendar, notes, messages, files, even screenshots. Overnight, a local AI model reads through them and writes what it learned into a folder of plain Markdown files. By morning, you have a personal knowledge base the AI genuinely uses. No cloud required for the heavy lifting.
The founders, Aditya Vellanki and Jesai Tarun — ages 18 and 20 — are obsessed with pushing on-device language models to their limits. Their custom inference stack, built on a LiteRT-LM fork, runs on Macs with just 8 GB of RAM. That’s the whole pitch: in the cloud, running inference on your life every day is expensive and a privacy nightmare. On your own chip, it’s free and private.
Two Features That Actually Matter
Sentient OS ships with two headline experiences, and both run on the context the night shift built.
Sidekick is the computer-use agent. Click your Mac’s notch, say “finish this for me,” and it picks up the task with its own on-screen cursor — working across your apps and browser while you keep doing your thing. Because it already has your context, you skip the briefing. One honest caveat: Sidekick can act without per-click approval once a task is underway, so review its automation permissions before delegating anything sensitive.
Double Tap drafts replies using your personal context and writing examples. Hit the right Command key and it writes back in your voice, informed by everything it learned overnight. For anyone drowning in email, that’s the killer feature.
Open Source and Private — With One Asterisk
The privacy story is genuinely strong where it counts. The built-in model analyzes only the sources you select, on your Mac, and the knowledge base lives there too. The app is open source under AGPL-3.0, so the claims are auditable rather than just asserted. That’s rare in the AI assistant world, and it matters.
The asterisk? Cloud features can receive context or screenshots if you enable them. So the local-first promise holds — as long as you keep the cloud toggles off. Worth knowing before you connect your entire inbox.
Pricing, Requirements, and Who It’s For
The app is free, and the official site advertises a launch offer: entering the code FINAL_1000 in the app keeps it free for life. If you plug in an external provider like ChatGPT or Claude, that provider’s charges are separate.
Requirements are strict: an Apple silicon Mac (M1 or newer) running macOS 15.4 or later. Windows users get a waitlist, not a product — for now.
Traction looks real. The alpha hit 4,000+ users in its first week with zero marketing, topped r/macapps for the month, and the team has raised over $1 million with Y Combinator’s Fall 2026 batch plus Afore and Pioneer Fund participating. Over 30 enterprises are reportedly already using it.
So who’s it for? Mac professionals buried in email and routine computer tasks — people who’ll actually review automation permissions and put the overnight memory to work. If that’s you, this is one of the most interesting AI tools of the year. If you’re on Windows, join the waitlist and check back later.
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