Zach Yadegari, co-founder of the calorie-tracking app Cal AI, launched a new startup called Persona that raised $10 million in a round led by Vine Ventures, with participation from Cory Levy, founder of Z Fellows, and Collective Global. Persona is developing a personal AI assistant that combines software with a wearable device.
The move comes months after MyFitnessPal acquired Cal AI in March for an undisclosed amount. According to TechCrunch’s reporting at the time, Cal AI’s annual revenue exceeded $30 million in less than two years, after the app surpassed older competitors in the app store rankings. Yadegari continued working at the acquiring company for a period before leaving in June and starting his next venture with a co-founder whose name has not yet been announced.
An Assistant Activated When Needed
Persona offers an assistant similar to services such as Instinct and Muse, but adds a $179 smart necklace that is expected to become available in December. Unlike devices that rely on continuous listening, Persona’s assistant will not be active ambiently at all times; it can be activated using a button on the wearable or through a wrist movement.
The app is still under development, while the company has launched a free beta version that allows users to interact with the assistant through iMessage messages. Yadegari said the beta attracted several thousand users and that the wearable had already generated five-figure revenue from preorders.
Privacy and Purchases with User Consent
The wearable does not run the AI model or store user data on the device; processing takes place in Persona’s cloud, with user data sent to it. The company says that data is encrypted in transit and at rest, and that users can delete their data. Yadegari also says that users’ conversations will not be sold to advertisers or data brokers.
Persona also says it is developing safeguards against phishing and prompt-injection attempts, two risks associated with AI agents. According to the company, the assistant will not be able to see credit card data, and purchases will require user approval, while payments will be handled through external providers such as Stripe Link.
What Changes in Practice?
Persona is betting on moving multiple daily tasks to a single interface, such as ordering food or taxis, taking notes, booking travel, and answering questions and emails. But this model places privacy and agent security at the center of the experience, especially because data is processed in the cloud and the assistant may take actions on the user’s behalf.
The company currently relies on advertising in its shopping research. Yadegari says sponsored results will appear among recommendations that he believes match the user’s preferences, while the assistant will not know which items are advertised. This leaves an open question about how the company will balance sponsored recommendations with the neutrality it promises, particularly before the device launches commercially.
Yadegari believes that everyday service apps may eventually merge into a “super app” operated through a single assistant. But Persona has not yet disclosed enough details about the final version’s capabilities or technical mechanisms, so the promises of a proactive assistant and reduced reliance on the phone screen remain tied to what the commercial version will demonstrate.