Spec Kit with Antigravity

[AJAskey]

I'm new to Antigravity, although I've coded quite a bit with Gemini Code Assist, and I've never used CLI. I've had some startup questions, and I noticed when I installed CLI, I got a message immediately saying, "You have to use Antigravity CLI, which is not supported." I would like some documentation. Tell me how to use Antigravity with the SPEC kit.

I've done these steps, and it seems to be working pretty well until now. It's time to use it, and I don't know what to do.
I am using PowerShell.

uv tool install specify-cli
specify init Proj1 --integration --script ps
specify version

After initialization, you should see the following commands available in your coding agent:

/speckit.specify - Create specifications
/speckit.plan - Generate implementation plans
/speckit.tasks - Break down into actionable tasks
/speckit.implement - Execute implementation tasks
/speckit.analyze - Validate cross-artifact consistency
/speckit.clarify - Identify and resolve ambiguities
/speckit.checklist - Generate quality checklists
/speckit.constitution - Create or update project principles
/speckit.converge - Assess codebase against artifacts and append remaining tasks
/speckit.taskstoissues - Convert tasks to issues

But when I type Gemini and try to do anything, I get this error message.
│
│ Failed to sign in. Message: This client is no longer supported for Gemini Code Assist for individuals. To continue │
│ using Gemini, please migrate to the Antigravity suite of products: https://antigravity.google

So then I opened up Antigravity, but I'm kind of lost in there. I need a step-by-step description of what to do in Antigravity. Is Antigravity instructions available here? Everything else is available, but I can't find anything on Antigravity.

Any help appreciated. Thank you, Andy.