Sentient OS

Key facts: Sentient OS runs a model on your Mac that reads your notes, emails, messages, calendar, files and screenshots while you sleep. By morning it has written what it learned into a folder of plain Markdown files you can open and edit. Click the notch and its Sidekick takes over a task with its own mouse cursor; double-tap the right Command key and it drafts a reply in your writing style. It is part of Y Combinator's Fall 2026 batch and open source under AGPL-3.0.

Plans: The tool is free, and its site says entering the code FINAL_1000 in the app keeps it free for life. It needs an Apple silicon Mac (M1 or newer) on macOS 15.4 or later; Windows is on a waitlist.

Best for: Mac users buried in email and small tasks who would rather their files stayed on their own machine. Who should skip it: Windows users, and anyone uncomfortable with an agent reading their messages and files, even locally.

Pros

• Your files stay on your Mac instead of going to a cloud service
• Overnight summaries arrive as plain Markdown you can open and edit anywhere
• Sidekick can take over a task, and reply drafting matches your writing style
• Free for life with the code published on its site, and open source

Watch out for

• Mac only for now, and needs Apple silicon plus macOS 15.4 or later
• Letting any agent read your messages and files needs real trust, even when processing is local
• A new Y Combinator product, so long-term support is still unproven

Best for

Mac users buried in email and small tasks who want a local-first helper. Who should skip it: Windows users, and anyone who does not want an agent reading their inbox at all.

Pricing

Free, with the site's FINAL_1000 code keeping it free for life. Check the official site for current terms.

FAQs

What does Sentient OS do overnight? It runs a local model over your notes, emails, messages, calendar, files and screenshots, then writes what it learned into Markdown files.

Does my data leave my Mac? It is built as an on-device product, so processing happens on your machine rather than in a cloud service.

Which Macs does it need? An Apple silicon Mac (M1 or newer) running macos 15.4 or later; Windows has a waitlist.

Is it open source? Yes, under the AGPL-3.0 licence.