Antigravity, an agent-driven IDE powered by Gemini 3 Pro, was tested by building a complete guest checkout feature with abandoned cart email recovery. The experiment involved multiple autonomous agents (Code, Terminal, Browser, Research) working across a React/Node/PostgreSQL stack. The agents successfully completed backend work, database migrations, and email integration in hours instead of days, though frontend debugging required significant manual intervention. The tool excels at multi-file scaffolding, routine backend wiring, and rapid prototyping, but struggles with UI polish and detailed business logic. Overall, it functions as a developer accelerator rather than replacement, dramatically reducing implementation time when agents maintain context.