Zach Yadegari, who co-founded the calorie tracking app Cal AI as a teenager, has moved on to a new venture called Persona—an AI agent startup that has already secured $10 million in funding. The investment round was led by Vine Ventures, with participation from Z Fellows founder Cory Levy and Collective Global. This comes after MyFitnessPal acquired Cal AI in March for an undisclosed amount, following Cal AI's rise above the more established calorie app in app store rankings. Yadegari wasted no time pursuing his next project. He's working alongside another co-founder whose identity hasn't been revealed yet.

That next project is Persona, a personal AI assistant in the vein of Instinct or Meta's Muse, but with a hardware element: a wearable band priced at $179 that will be available soon. One key distinction is that Persona won't function as ambient AI—it won't be constantly listening or recording. Instead, the band features a button to activate the assistant, or users can set it to activate with a wrist flick. According to Yadegari, Persona was built with user privacy as a priority. The AI model doesn't run on the device itself, nor does the device store user data. Rather, the model operates in Persona's cloud, and user data gets transmitted there. The assistant safeguards privacy through encryption of data both in transit and at rest. The company also says users have the ability to delete their data. This approach aims to ensure user conversations remain private and can't be sold to advertisers or data brokers. Yadegari notes that the team is also building in protections against phishing and prompt-injection attacks—two vulnerabilities that AI labs like OpenAI acknowledge can affect agents. Additionally, he promises that Persona's agent cannot access a user's credit-card information, and any purchases will need user approval, with payments processed through third-party providers like Stripe Link. Link is Stripe's secure wallet built specifically for agent use. Even though user data won't be sold to advertisers, the startup's current revenue model does depend on advertising. Yadegari explains that the company will display advertised products during shopping research. However, he maintains that the agent will offer unbiased recommendations because it won't be aware of which items are sponsored. For instance, if someone is looking into office chairs, he says, "the agent knows their preferences" and will present chairs matching those preferences, some of which happen to be sponsored results. The bands are slated to ship in December, and an app is currently in development. In the interim, Persona has debuted as a free beta product where users interact with the assistant through iMessage texts. It has drawn "a few thousand beta users," according to Yadegari. The band has also brought in "five figures in preorder revenue" so far.

Like other consumer AI assistants, Persona can handle tasks such as ordering food or rides, taking notes, booking travel, and answering questions and emails, among other functions. "All of the utility apps that you use on your phone day-to-day, whether those are apps for shopping, whether it's Uber, DoorDash, your email - these are all collapsing and will collapse into a single super app powered by an AI assistant," Yadegari said. Ultimately, he aims to make Persona increasingly proactive. "It can offer help and solve problems before you even know you have a problem, and overall be more seamless with your life, so that you don't need to stare at a rectangle in your hand all day." Disrupt is scheduled for October 13-15 at the Moscone Center in San Francisco. Prior to Cal AI, Yadegari started his first business in ninth grade and sold it for $100,000 at age 16.