Antigravity 2.0 in one day: the four shells and what each is good for

Arthur
This is a submission for the Google I/O Writing Challenge A field guide to the four ways Antigravity 2.0 lets you drive an AI coding agent, with a 10-minute SDK recipe for writing your first skill. The architectural news worth keeping The most useful sentence Google I/O 2026 produced was not on the main stage. It was Kevin Howe, in the Google Cloud Live segment afterward, defining the term that had been circling the keynote all morning. Asked what a harness actually is, Howe gave the answer in t