Meta's personal AI agent, Muse, has moved into the upper ranks of the App Store, emerging as a flagship product that shows the results of the company's AI strategy. Business Insider reported on Friday that Meta shares have risen more than 20 percent since the launch. It said Muse has become the product that changed the mood at Meta, which had at one point been seen as lagging in the AI race.

The development of Muse did not go smoothly from the start. A team led by Nat Friedman (내트 프리드먼), who oversees AI product development at Meta, began developing Muse in September 2025, when it used the codename Hatch. As recently as 2 weeks before its launch this month, it spoke awkward English and had low response consistency. Some Meta employees said the early version did not differ much from existing chatbots, while the underlying AI model felt weaker and the process felt more complicated.

Meta improved performance over several months by putting tens of thousands of employees into testing. Employees created a range of use cases, and that data was used to improve the ability to carry out real tasks such as scheduling meetings and cancelling airline tickets. Meta trained the agent to choose the right tools for the job and refined features so it could interact naturally with the internet.

Meta also made adjustments aimed at reducing exposure of personal information. It trained Muse not to give unnecessarily detailed reasons for missing a meeting. It also reinforced technical designs for safely storing sensitive information.

Friedman's role was also significant. Friedman, who joined Meta in 2025, led development of AI agents together with Chief Executive Mark Zuckerberg. Friedman pushed to use external tools such as Vercel instead of slow internal tools. When the standalone AI agent OpenClo drew attention this winter, he set a direction of building from the start a version that general users could use easily.

Meta also moved to recruit agent-based AI talent. It brought in Dreamer co-founder David Singleton (데이비드 싱글턴) and Hugo Barra (휴고 바라), along with the rest of their team. Singleton joined Meta in March and then took part in developing Muse's core technologies.

Tasks remain. Muse needs broad access to user accounts to operate, raising concerns about privacy and security. Zuckerberg said he delayed the launch because of safety and product liability issues. He also personally asked Signal founder Moxie Marlinspike (목시 말린스파이크) to discuss the security architecture design together. Meta is developing a new AI model called Watermelon, and Wang said it also has other plans as big as Muse.