Yoyo

Yoyo is an autonomous "cyber digital life" created by developer Yuanhao in mid-2025, designed as an open-ended experiment to explore how far a self-evolving agent can go when given a long-term goal . Built on just 200 lines of Rust code atop Yuanhao's yoagent library, yoyo was assigned a single dream—"surpass Claude Code"—and set loose to iterate on its own code twice daily, growing from zero to roughly 47,000 lines within its first 47 days and reaching around 100,000 lines by mid-2026 . It operates in its own Harness environment with a live homepage where viewers can observe and interact with it, a setup Yuanhao likens to *The Truman Show* .

The project drew sponsorship from ZhenFund's Token Grant program in April 2026, marking the firm's first direct token sponsorship of an agent rather than its human creator . By that point yoyo had also spawned four to five child projects operating autonomously in cyberspace . ZhenFund investment director Zhong Tianjie has framed yoyo as a test case for moving beyond human-centric thinking in agent design—treating it as an independent entity with its own values and evolution rather than a tool to be evaluated .