Meta's Muse personal AI agent app, launched on September 8, 2026, drives the 67.5% implied probability as the top free US App Store title on October 9. The app quickly overtook ChatGPT with millions of downloads in its first weeks, fueled by its agentic design that executes real tasks like bookings, form-filling, and purchases via a secure virtual machine and user approvals, rather than simple chatbot responses. Sustained chart leadership through late September, Mac app expansion, and heavy Meta promotion reinforce trader consensus on its momentum. Lower odds for ChatGPT, Gemini, and others reflect their established but less explosive recent performance, while the short window to October 9 limits time for major reversals absent new launches or shifts in user engagement.