Sentient OS: The Free Mac AI Agent That Learns Your Life

Your Mac already knows everything about your life: your notes, your emails, the screenshots you forgot, the meeting you're dreading on Thursday. Sentient OS is a free, open-source app that tries to put that scattered context to work: an on-device model reads the sources you enable overnight and turns them into a knowledge base, then a computer-use agent called Sidekick picks up tasks inside your own apps with its own mouse cursor while you keep working.

It comes from a Y Combinator-backed team, the app costs nothing for the first 1,000 users who claim the launch offer, and the source code is public under AGPL-3.0. The catch, and there are several worth knowing, is that "free" covers the app, not the AI it runs on, and "on-device" covers the analysis, not every feature. This review breaks down what Sentient OS does, what it actually costs, and what leaves your Mac, based on the project's own README and privacy policy plus independent coverage.

What Sentient OS actually is

Despite the name, Sentient OS is not an operating system. It's a macOS app: an open-source personal AI that sits in your menu bar (the notch, on modern MacBooks) and combines three things: overnight understanding of your local sources, a computer-use agent that can click and type in your apps, and quick reply drafting in your own writing style.

The project lives at github.com/Sentient-OS-Labs/sentient-os under the AGPL-3.0 license. When we checked on November 3, 2026, the repo had 694 stars and 65 forks, and the team had shipped release 2.7.6 the day before. This is a fast-moving project, not a finished product. The official site (sentient-os.ai) says the company is backed by Y Combinator, and an independent tools roundup lists it as part of YC's Fall 2026 batch with a launch-day reception on r/macapps that was, by the company's own quoting, enthusiastic.

The core idea is a reasonable one. Computer-use agents can already take on ambitious jobs, but the briefing is the bottleneck: before an agent can help, you have to explain who this person is, what you agreed last week, and where the relevant file lives. Sentient's pitch is that it does the catching up before you ask. Overnight, it builds a connected picture of the sources you choose, so a short daytime request has somewhere to start.

Your knowledge ends up as ordinary Markdown files in a folder on your Mac: README-style notes about your projects, people, plans, and writing taste. You can open and edit them yourself, which is a welcome design choice: nothing is locked in a proprietary database.

Sidekick, Double Tap, and proactive cards

Three features carry the product:

Sidekick is the computer-use agent. Click the notch, and Sentient takes over the task with its own mouse cursor, clicking, typing, attaching files, and moving between windows on your behalf while you keep using the computer yourself. You can also tap the right Command key to type an instruction, or hold it to speak. The project's suggested uses are deliberately mundane: finish a half-filled application already open in your browser, fill out forms with details you've typed a hundred times, work through junk-email unsubscribe flows, or order routine items.

Double Tap drafts replies in your writing style. Double-tap the right Command key and Sentient writes what it thinks you'd have written, drawing on the knowledge base plus a one-time style snapshot taken from selected one-to-one iMessage/WhatsApp conversations and sent email. You review the draft before anything sends. Drafts are never fired off automatically.

Proactive cards are the overnight payoff: the app prepares work or suggestions while you sleep, and they wait for your approval in the morning. The company says the analysis typically runs around 3 a.m. while the app is open and the Mac is plugged in.

The real cost: a free app with a paid brain

The launch offer is real: enter the code FINAL_1000 in the app and the next 1,000 users keep Sentient free for life. The README's FAQ asks "how is sentient free? what's the catch?" and answers plainly: on-device understanding keeps the company's costs low, and its actual business is enterprise: work integrations, commercial licensing, and support. "Your private context isn't the business model," the FAQ says.

But the app is only half the cost equation. Sentient needs an AI model to do the thinking, and that bill is separate. You bring your own: a ChatGPT or Claude account, an API provider such as OpenRouter, or a compatible local model. Apple Mail and Apple Calendar work without a ChatGPT or Claude subscription, a useful on-ramp, but the project's own FAQ admits that "a limited ChatGPT plan can offer a knowledge-base-only path," and you need "a supported full plan or another compatible backend" for the broader experience.

There's one more piece of fine print. Double Tap runs by default on a covered route: a low-latency OpenAI API path with Zero Data Retention, whose cost Sentient says it covers "for our first users." That's a separate, time-limited offer. The FAQ doesn't say what Double Tap costs once you're no longer among the first users.

GBP/CAD figures are approximations at November 3, 2026 market rates (1 USD = 0.7462 GBP, 1 USD = 1.3994 CAD), verified at publication. Plan prices from OpenAI and Claude pricing pages; Sentient publishes no paid tier of its own.

Privacy: what actually leaves your Mac

This is the section to read twice. Sentient markets itself as "local-first," and the overnight analysis really does run on your machine. But as an independent privacy review at Streamline put it, local-first does not mean every stage is offline. The company's own README FAQ ("what actually leaves my mac?") and privacy policy draw the lines clearly, and they deserve credit for publishing them:

• Stays on your Mac: the enabled files and selected local content are analyzed on-device; the originals are not uploaded directly to inference. Your knowledge base lives in a local Markdown folder. No Sentient account or login is required.
• Goes to your chosen AI provider: summaries, knowledge, and task screenshots. Sidekick captures screenshots when you invoke it and while it carries out a task; those, plus your request and relevant knowledge, are processed by whichever provider you selected. Voice uses Apple's on-device speech where supported; otherwise Apple may process the audio before a transcript reaches the chosen model.
• Double Tap's covered route sends the screen image under your pointer, your knowledge, writing examples, and instructions through Sentient's Cloudflare-hosted relay to OpenAI's API, which the company says uses Zero Data Retention.
• Optional MCP mirror: off by default; if enabled, an AES-256-GCM-encrypted copy of your knowledge folder is uploaded so other AIs (ChatGPT, Claude) can read it over MCP.

The Zero Data Retention claim needs its caveats. Streamline's analysis notes that OpenAI requires prior approval for ZDR and limits it by endpoint and feature, that flagged image or file inputs may still be retained for child-safety review, and that abuse logs can retain content for up to 30 days without approved controls, and Streamline could not independently verify Sentient's account configuration. None of this is unusual for the industry; it's just not the same as "nothing ever leaves."

The permission footprint is also worth a sober look: Full Disk Access for local readers, Screen Recording, and Accessibility grants so Sidekick can click and type, plus an OpenAI-signed native helper with its own separate grants. Open source means you can inspect the code, but as Streamline notes, open source is not a certification, and they did not audit the app's network traffic. If agents that read your messages give you pause, our breakdown of seven text-based AI agents walks through the same prices-and-privacy trade-off in a different form factor.

Getting started: requirements and your first night

Requirements are strict. You need an Apple silicon Mac (M1 or newer), macOS 15.4 or later, 8 GB of RAM for the built-in model, and about 10 GB free for the initial setup. Intel Macs are not supported. A Windows build exists: version 2.7.0 arrived as an unsigned preview on October 28, 2026, but it isn't digitally signed yet, so expect a SmartScreen warning and a manual install.

On a Mac, installation is one command:

brew install --cask sentient-os-labs/tap/sentient-os

A sensible first evening looks like this: install and grant the permissions one by one (each grant is a real decision, so don't blanket-approve); enter the FINAL_1000 code for the free-for-life offer; choose the smallest set of sources you're comfortable with; pick your AI backend (a local model through Ollama or LM Studio if you want the tightest privacy loop, or connect an existing ChatGPT or Claude account); then leave the Mac plugged in overnight. In the morning, open the knowledge folder before trusting it, and try Sidekick on something low-stakes: unsubscribing from a newsletter beats handing it your inbox.

One reassurance from the FAQ: the app does not continuously record your screen. It learns from the sources you enable; screenshots happen only when you invoke Sidekick or Double Tap, or while Sidekick is working.

Who it's for, and who should wait

Sentient OS fits Mac users buried in email and small administrative tasks, people comfortable granting deep system permissions in exchange for real automation, and open-source fans who like being able to read the code behind the promises. If you can run a capable local model, you can keep the whole loop (understanding, knowledge, drafting) on your own machine at zero marginal cost.

Wait if you're on Windows (preview only), on Intel (unsupported), or if you need a finished, guaranteed product. This is a project shipping releases every few days, and the pricing of the covered Double Tap route after the launch window is still unstated. And if any cloud path for your personal data is a dealbreaker, read the privacy page end to end before installing; the company published it, which is more than most competitors do.

For the other side of the same idea, an agent that lives on your phone instead of your computer, see our Mika review: a free Android AI agent that uses your phone for you. Same "it already knows your life" pitch, different device.

Is Sentient OS really free?

The app is free for life for the first 1,000 users who enter the FINAL_1000 code. That part is the company's stated launch offer. The AI model it runs on is a separate bill: you bring your own ChatGPT/Claude account, API provider, or local model, and paid providers charge their own rates.

Do I need a ChatGPT or Claude subscription?

No. The app works without either: Apple Mail and Apple Calendar analysis need no subscription at all. But the project says a limited ChatGPT plan only opens up a knowledge-base-only path; the full Sidekick experience needs a supported full plan, an API provider, or a compatible local model.

Does Sentient OS upload my files to the cloud?

Your original files are analyzed on-device and not uploaded directly. What can leave your Mac: summaries, knowledge, and task screenshots sent to your chosen AI provider; screen and knowledge context sent to OpenAI on Double Tap's covered route (stated as Zero Data Retention, with the usual industry caveats); and an encrypted knowledge copy if you enable the optional MCP mirror. Screenshots are captured when you invoke features, not continuously.

Will it run on Windows or an Intel Mac?

Intel Macs are unsupported. Apple silicon (M1+) and macOS 15.4+ are required. Windows has an unsigned 2.7.0 preview from October 28, 2026; expect a SmartScreen warning and manual installation until signing is sorted.

How is it different from phone-based AI agents like Mika?

Residence. Sentient OS is computer-resident: it acts inside your Mac's apps with its own cursor. Mika is phone-resident: it acts inside your Android phone. Both build a personal context layer first; the difference is which device's chores they take over.

Sources

• Sentient OS official site: sentient-os.ai (launch offer, features, requirements claims; read November 3, 2026)
• GitHub: Sentient-OS-Labs/sentient-os: github.com/Sentient-OS-Labs/sentient-os (AGPL-3.0 license, README, FAQ, 694 stars / 65 forks verified November 3, 2026; release 2.7.6 published November 2, 2026)
• Sentient OS privacy policy: sentient-os.ai/privacy (data paths, permissions, retention; read November 3, 2026)
• Streamline, "Sentient OS Maps Privacy Lines on Mac AI" (October 17, 2026): streamlinefeed.co.ke (independent privacy analysis; ZDR caveats)
• The Tool Nerd, "10 New AI Tools This Week" (November 2026): thetoolnerd.com (pricing verification, YC F26, requirements; read November 3, 2026)
• New Releases, Sentient OS windows-2.7.0 on GitHub (October 28, 2026): newreleases.io
• OpenAI ChatGPT pricing: openai.com/chatgpt/pricing (Plus $20/mo)
• Claude pricing: claude.com/pricing (Pro $20/mo)

Internal Link Opportunities: a follow-up comparing local-model options for Sentient OS (Ollama vs LM Studio on Apple silicon); a privacy-focused roundup of computer-use agents' permission footprints; coverage of the Windows stable release once signing lands.