TL;DR: Antigravity 2.0 replaces Gemini CLI with a faster Go-based CLI (agy), adds an SDK for custom agent workflows, and ships a Dart & Flutter MCP server that gives agents live context of your running app. The migration deadline is June 18, 2026. The three things that matter most for Flutter devs: AGENTS.md, Agentic Hot Reload, and the Stitch → MCP → Flutter pipeline.

Gemini CLI is being retired on June 18, 2026. If you're a Flutter developer who uses it, you're not just upgrading a tool; you're migrating to a different model of how AI fits into your workflow. Antigravity 2.0, announced at Google I/O 2026 alongside Flutter 3.44, is not a rename. It's four distinct surfaces where one VS Code fork used to be:

• Antigravity Desktop: IDE-style editor with an integrated agent panel
• Antigravity CLI (agy): terminal-first agent built in Go, fast and scriptable
• Antigravity SDK: programmatic API for custom agent workflows
• Managed Agents: cloud-isolated Linux environments spun up with a single API call

This article focuses on the three things that give Flutter developers a real, practical edge, not the marketing overview.

1. AGENTS.md: Your Project's AI Constitution

What is AGENTS.md? It's a Markdown file you place at the root of your Flutter project. Antigravity reads it at the start of every agent session and uses it as a standing instruction set for the entire project. It replaces the habit of copy-pasting your architecture rules into every prompt.

# Project Agent Rules

- Architecture: Clean Architecture, feature-based folder structure
- State management: Riverpod (prefer AsyncNotifier over FutureProvider)
- Never hardcode colors, always use ThemeData tokens
- Run `flutter analyze` before suggesting any code change
- Target Flutter 3.44+, Dart 3.4+
- Localization: use flutter_localizations, never raw strings in widgets

Drop this in version control. Every developer on your team, and every agent session, starts with the same context. Onboarding a new agent is now the same as onboarding a new developer.

The file is also backward compatible: GEMINI.md is still read, but AGENTS.md takes priority when both exist.

2. Install the Antigravity CLI and Migrate Today

What is agy? It's the Antigravity CLI, a terminal-based agent built in Go that replaces gemini. It's faster, ships with a proper TUI, and shares the same underlying model and plugin system as the desktop app.

# macOS / Linux
curl -fsSL https://antigravity.google/install.sh | bash

# Windows (PowerShell)
irm https://antigravity.google/install.ps1 | iex

# Verify
agy --version  # agy version 2.0.0

If you have existing Gemini CLI config, migration is either automatic on first run (it detects and prompts) or manual:

agy plugin import gemini

Your Agent Skills, Hooks, Subagents, and Extensions (now called Antigravity Plugins) carry over. Global config lives in ~/.antigravity/ going forward.

3. Enable the Dart & Flutter MCP Server

What is the Flutter MCP server? MCP (Model Context Protocol) is a standard for giving an agent live, structured access to your development environment. The Dart & Flutter MCP server lets Antigravity read your widget tree, active routes, Dart analysis output, and running app state, without you pasting code into the chat.

Install it inside Antigravity IDE:

1. Open the Agent panel with Cmd/Ctrl + L
2. Search for Dart & Flutter MCP server
3. Install and restart

Once enabled, the agent can see what's in your running emulator and act on it. This is what makes Agentic Hot Reload work.

4. Agentic Hot Reload: Prompt-to-Emulator in Seconds

What is Agentic Hot Reload? When Antigravity's agent modifies a Flutter file, it triggers Flutter's hot reload automatically. No manual r. No switching windows. You describe a UI change in the Agent panel, the Dart file updates, and the emulator reflects it in place.

Enable it by switching to Agent-driven mode in Antigravity settings. In this mode the agent runs commands (including hot reload) without asking for per-step approval. For production projects, use Review-driven mode instead, with the same capability but the agent pauses and asks before executing commands like flutter pub add or file deletions.

5. The Stitch → Antigravity → Flutter Pipeline

How do you go from a design to a running Flutter app with Antigravity? The workflow the Flutter community has been building around uses three tools in sequence.

Build the habit tracker screen from the Stitch export.
Follow Clean Architecture. Use Riverpod, Material 3 tokens, 
support light and dark mode. No hardcoded strings.

In 10–12 minutes you have runnable Flutter + Dart code. Then flutter run.

What to review manually: Complex async state, platform channels, native plugin integrations, and anything touching sensitive permissions. The agent handles scaffolding well; business logic edge cases still need a human pass.

6. Antigravity SDK: Automate Your Flutter Agent Workflows

What is the Antigravity SDK for? It gives you programmatic access to the same agent harness that powers the desktop and CLI, optimized for Gemini 3.5 Flash (currently the default model, 4x faster than the previous generation, higher benchmark scores). Use it to:

• Run a Flutter lint-and-fix agent as a CI step before PR merge
• Build a custom agent that understands your design system tokens and enforces them across generated code
• Automate multi-step workflows: generate → test → fix → commit, with Managed Agents providing the isolated Linux environment for each run

Managed Agents spin up a full isolated environment with a single API call and maintain persistent state across multi-turn sessions, useful for long-running tasks like migrating a large Flutter codebase to a new API.

Pricing Reference

Deadline: Free Gemini Code Assist for individuals stops serving requests on June 18, 2026. You need a plan or the CLI migration before that date.

What This Changes in Practice

Antigravity 2.0 doesn't change what good Flutter code looks like. Clean Architecture is still Clean Architecture. Riverpod still behaves the same way. What changes is how much of the scaffolding and boilerplate you write yourself.

The developers getting the most out of it treat AGENTS.md seriously, use Review-driven mode on anything that touches production, and keep human review on complex state logic and native integrations. The agent is fast at the right things. Know what those things are, and you get the speed without the rework.

Sources: Flutter docs — Antigravity · Flutter docs — Antigravity CLI · Google Developers Blog — Gemini CLI to Antigravity CLI transition · TechCrunch — Google I/O 2026 coverage · MarkTechPost — Antigravity 2.0 full breakdown