An Old Android Becomes the Body of an AI Assistant: dex Can Open a Browser, Call a CLI, and Fill In Accounts by Itself

Srivatsa Rampalli turned an old Android into the always-on body of personal agent dex. It is always online, with voice in and voice out: TTS uses Kyutai Labs, and STT uses SarvamAI. dex has its own browser and can also call the custom CLIs he wrote for each tool. Credentials are not stuffed directly into the model; they are kept in a vault, and browser fields are filled in only after typesafeai validates them. This pipeline is far more concrete than "book a ticket for me" in a chat box: the agent has to see the page, locate the input fields, get the keys, and complete the submission.

In the video, dex's screen is stopped on a countdown for an F1 qualifying session: NEXT IN 2H 10M, date SUN 25 OCT, and a digital clock in the lower left shows 00:14. The scene is very ordinary, and it also explains what always on means: the agent does not exist only when you open some app; it is waiting inside the phone.

There is also a detail in the replies. The first confirmation comes from jev: it picks one phrase from 20 phrases based on the query. The user hears a quick, human-like response while the backend agent works at the same time. The design is not complicated, but it solves the cold-start awkwardness of voice assistants. With no feedback while waiting, users do not know whether it heard them. The 20 phrases give the confirmation sound variation without slowing down the task.

Using an old phone as an agent body has practical advantages. The screen, microphone, speaker, network, and battery are all there, and the cost is low; always on means the agent does not depend on some desktop window. The hard part is permissions and credentials. If browser autofill of accounts goes wrong once, the risk is greater than in chat. dex handles credential insertion separately with a vault and field validation, and this direction is worth watching. Many agent products stop at demo videos; dex puts tool calls, the browser, voice, and security boundaries into a single phone. After retiring, an old Android became the physical body of an AI—that counts as a pretty good re-employment.

Original tweet: https://x.com/svatsa159/status/2114231045273100601