Gemini CLI → Antigravity CLI

By the end of this lesson, you’ll have a Google AI CLI running — Antigravity CLI if you’re an individual, Gemini CLI if you’re on an enterprise license — and understand when to reach for it.

What changed — and why

Gemini CLI was Google’s popular open-source command-line agent (tens of thousands of GitHub stars). In May 2026, Google announced it is consolidating its terminal agent into Antigravity CLI, a new Go-based agent that runs asynchronous multi-agent workflows in the background. Consumer Gemini CLI access ends 2026-06-18; enterprise licenses keep Gemini CLI running.

Antigravity carries over the same ideas you’d learn in any modern CLI agent — Agent Skills, Hooks, Subagents, and Extensions (now called “Antigravity plugins”) — though not at full 1:1 parity yet. Unlike Gemini CLI, Antigravity CLI is not open source.

The good news: the skills transfer directly. Whichever Google CLI you run, you’re still directing a Gemini-model agent from your terminal — and everything you learn here applies to Claude Code and Codex CLI too.

What you get

Both Antigravity CLI and (enterprise) Gemini CLI drive Google’s Gemini models from the terminal:

• Massive context: ~1 million tokens — read enormous codebases in one pass
• Gemini 3 family models (3 Pro, 3.5 Flash) with Auto routing — simple prompts go to Flash, complex ones to Pro
• Plan-first workflows: review and approve a strategy before the agent executes
• Project context files that give the model persistent instructions (like Claude Code’s CLAUDE.md)
• MCP-extensible: connect external tools and services
• Async multi-agent workflows (Antigravity): kick off background work and check results later

Install Antigravity CLI (individuals)

Step 1: Install

curl -fsSL https://antigravity.google/cli/install.sh | bash

curl -fsSL https://antigravity.google/cli/install.sh | bash

irm https://antigravity.google/cli/install.ps1 | iex

The installer adds the agy command (it lands in ~/.local/bin on macOS/Linux). Verify:

agy --version

Step 2: Authenticate

Start Antigravity CLI:

agy

It opens your browser to sign in with your Google account. Sign in, and you’re done.

Your first interaction

Step 1: Create a project folder

mkdir hello-agy && cd hello-agy

Step 2: Start the CLI

agy

Run agy --help first if you want to see the available subcommands — the tool is new and its surface is still settling.

Step 3: Give it a task

Create a simple HTML page with a counter. It should have a dark
background, a large number in the center, and + / - buttons to
increment and decrement. Use vanilla JavaScript — no frameworks.

Watch as the agent:

1. Plans the approach
2. Creates the file(s)
3. Writes the HTML, CSS, and JavaScript
4. Reports what it did

Step 4: Check the result

ls
cat index.html

open index.html

explorer.exe index.html

xdg-open index.html

A Google CLI vs Claude Code

Both are excellent. Here’s how they compare:

Context windows and model capabilities change frequently — check each tool’s official docs for current limits. Many people use both: a Google CLI for broad exploration over big codebases, and Claude Code for complex, multi-step work where reasoning quality matters most.

Enterprise: keeping Gemini CLI

If your organization has a Gemini Code Assist Standard or Enterprise license (or Gemini Code Assist for GitHub via Google Cloud), Gemini CLI keeps serving requests past the June 18 cutover with continued model access and updates. Install it the usual way:

npm install -g @google/gemini-cli
gemini --version

Authenticate with your licensed Google Workspace account. Gemini CLI’s in-session commands — /help, /plan (Plan Mode), /model, /memory show, /memory reload, /clear — and GEMINI.md project-context files work as before.

Tips

1. Take advantage of the large context. A 1M-token window can hold very large codebases — don’t hesitate to point it at big projects.

2. Use plan-first workflows for anything non-trivial. Review the strategy before letting the agent execute.

3. Set up project context early. Even a few lines (“This is a Python Flask app, we use pytest, follow PEP 8”) makes every response better. Gemini CLI uses GEMINI.md; check agy --help for Antigravity’s project-context file.

4. Lean on async multi-agent runs (Antigravity). Kick off longer background work and check the results when it’s done, rather than babysitting the terminal.

5. Run --help when a command isn’t what you expect. Antigravity CLI is new and its commands are still settling — the tool is the source of truth, not your memory.

Verify it works

agy --version

You should see a version number. If you get “command not found,” revisit the installation step (and confirm ~/.local/bin is on your PATH).

Key Takeaways

• Consumer Gemini CLI ends 2026-06-18 — individuals move to Antigravity CLI (agy); enterprise Gemini Code Assist licenses keep Gemini CLI
• Install Antigravity CLI from antigravity.google — it’s new and evolving, so verify commands against the official docs
• ~1M-token context lets a Google CLI read more of your project than most other tools
• Plan-first, then execute — review the strategy before the agent runs
• For government/regulated work, use an enterprise license, not a personal free tier — route tool access through your security office
• Pair it with Claude Code — a Google CLI for broad exploration, Claude for precision reasoning