Sentient OS spends the night building context for your next task

Sentient OS wants to do the preparation that usually falls to the person using an AI assistant. Its Mac app analyzes connected local information overnight, building a personal knowledge base that it can draw on when drafting a reply or taking over a task on the computer.

The launch centers on two ways to use that context. Double Tap inserts a suggested response into the email or message field where the user is already typing. Sidekick works across applications and the browser with its own cursor, taking on jobs such as preparing an investor update or finishing an application.

Founders Jesai Tarun and Aditya Vellanki describe the underlying problem as scattered information: messages, files and notes contain details an assistant needs, but manually assembling those details can become a task of its own. Sentient’s answer is to process the material ahead of time, rather than asking users to explain their situation each time they need help.

The company says its custom inference stack runs on Apple silicon Macs with as little as 8 GB of RAM. The resulting knowledge base is an editable folder of Markdown files. Users can inspect and correct what the software has recorded, or use those files with other AI tools.

That file format is a consequential design choice. Personal context can become stale or simply be wrong. Keeping it in readable documents gives users a direct way to check the assistant’s understanding, although it does not establish how accurately the system extracts information in the first place.

Watch Sentient OS’s original launch demonstration.

The on-device claim also needs a distinction. According to the announcement, connected local sources are analyzed on the Mac. Sidekick can use an existing ChatGPT or Claude subscription, and cloud-powered features receive context for the task. Compatible local models are another option. Local preparation therefore does not mean that every possible workflow keeps all information off external services.

For Double Tap, users click into a reply field and press the right Command key twice. The app generates a draft using personal context and writing style, leaving the user to review and send it. Sidekick begins from the Mac’s notch, where the user can ask it to continue work already underway. The launch describes a handoff that avoids rebuilding the entire task history in a chat window.

Sentient says more than 10,000 people use the app, including users at over 130 companies. Those figures are company-reported adoption claims; people using software at a company should not be confused with a company-wide deployment or customer contract. The startup belongs to YC’s Fall 2026 batch and has made its code available through an official open-source repository.

The website offers a Mac download and a Windows waitlist. For now, the practical test is on the Mac: whether the knowledge assembled overnight is accurate enough to make the next reply or task meaningfully easier to review and finish.