Gemini CLI Deprecated Today! Complete Steps for Migrating to the Successor agy

Complete Migration Guide from Gemini CLI (Discontinued June 18) to Successor "Antigravity CLI (agy)"

Many people might be surprised to find that Gemini CLI suddenly became unusable today. At the developer conference "Google I/O 2026," Google announced that it would discontinue the personal and free service of "Gemini CLI," a command-line AI tool loved by many developers, as of June 18, 2026. Along with this, users are transitioning to the new successor AI agent for terminal, "Antigravity CLI (command name: agy)."

While Gemini CLI gained massive popularity as an open-source interactive CLI, this transition will provide even more powerful features, such as faster execution binaries and parallel autonomous background task processing. In this article, we will comprehensively explain the scope of impact of the deprecation deadline, the powerful features of the new "agy" command, concrete migration steps, and clean uninstallation methods for the old Gemini CLI.

Scope of Discontinuation Impact and Background of the Migration

Since its open-source release in June 2025, Gemini CLI has built a highly active community, accumulating over 100,000 stars on GitHub and having more than 6,000 pull requests merged. The complete transition to the successor tool, which includes turning it into "closed source," has sparked major debates with mixed opinions in the developer community.

This discontinuation and migration deadline of "June 18, 2026" primarily applies to free users, Google AI Pro/Ultra plan subscribers, and individual Gemini Code Assist users. On the other hand, users using Gemini CLI via enterprise Standard/Enterprise licenses or Google Cloud such as Vertex AI are unaffected at this point and can continue using the old CLI. However, since all future feature development will focus on Antigravity CLI, it is wise to consider migrating in the long term.

Performance and New Features of the Successor Tool "Antigravity CLI (agy)"

The new tool "Antigravity CLI (command name: agy)" has been completely rewritten in Go, moving away from the conventional TypeScript/Node.js implementation. As a result, memory consumption is significantly reduced, and startup and response speeds are dramatically improved. Furthermore, by adopting the state-of-the-art "Gemini 3.5 Flash" as its standard model, it can handle complex development workflows more smoothly than ever before.

The most notable new feature is "Asynchronous Parallel Background Sub-Agents." Time-consuming tasks such as large-scale code refactoring, document creation, and test automation can be executed in the background, allowing you to work in parallel without blocking the terminal operation screen. In addition, there are plenty of shortcuts to enhance interactive development efficiency, such as the ability to select and attach files by typing "@" during interactions, or invoking shell commands directly using "!".

Comparison Item	Gemini CLI (gemini)	Antigravity CLI (agy)
Implementation Language	TypeScript (Node.js)	Go
Startup/Operation Speed	Standard	Extremely fast / memory-efficient
Multi-Agent Support	Not supported (Single task)	Supported (Background asynchronous parallel)
Development/Distribution Model	Open Source (Apache 2.0)	Closed Source

Step-by-Step Migration Procedure to Antigravity CLI

The migration process is simple and is executed mainly by following these steps:

Step 1: Installation In macOS or Linux environments, run the following installation command in your terminal.

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

For Windows environments (PowerShell), run the following:

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

Step 2: Initial Run and Authentication Once the installation is complete, run the agy command in your terminal. The browser will automatically open and the Google OAuth authentication flow will begin. Sign in using the Google account you were using with the legacy Gemini CLI.

Step 3: Import Existing Configuration By running the following command, environmental settings such as Gemini CLI's MCP server configuration, keybindings, and allowed commands will be automatically imported into Antigravity CLI. agy plugin import gemini

Step 4: Fine-Tuning MCP Configuration After importing, check the MCP server configuration file mcp_config.json. In the connection destination specification inside the settings, the traditional url field has been changed to serverUrl. If connection errors occur, please update the description manually.

Step 5: Migrating Project Skills Directory If you are using custom-defined Agent Skills within your project, you need to migrate (copy or rename) the contents from the legacy Skills placement directory .gemini/skills/ to the new path .agents/skills/.

mkdir -p .agents/skills && cp -r .gemini/skills/* .agents/skills/

Step 6: Operation Verification Finally, run the agy doctor command to perform diagnostic tests on the settings and connection status. If no issues are detected, the migration is complete.

Uninstallation Steps for the Defunct Gemini CLI

Once the migration to Antigravity CLI is complete, it is recommended to cleanly remove (uninstall) the old, unused Gemini CLI from your system.

1. Removing the Global Package

Gemini CLI is typically installed as a global npm package. Run the following command to uninstall it:

npm uninstall -g @google/gemini-cli

* If a permission error occurs on macOS/Linux, prepend sudo to the command and run it again.

2. Deleting Configuration Files and Cache

Since credential information and local configurations remain, delete the unnecessary directories. For macOS/Linux, delete the ~/.config/gemini-cli directory.

rm -rf ~/.config/gemini-cli

For Windows (PowerShell), delete the configuration files and cache with the following command:

Remove-Item -Recurse -Force $env:USERPROFILE\.config\gemini-cliRemove-Item -Recurse -Force $env:LOCALAPPDATA\gemini-cli

3. Cleaning Credentials

Delete the old OAuth tokens saved in the OS credentials storage. For Windows, open "Credential Manager" and delete registration entries related to google-gemini-cli or gemini-cli under "Windows Credentials." For macOS, search for and delete similar related entries using the "Keychain Access" app.

Alternative Tools if You Are Concerned About the Transition to Closed Source

For developers who have concerns regarding the closed-source transition of Antigravity CLI, several excellent open-source alternatives are available:

1. Claude Code:

The latest agent tool for the terminal provided by Anthropic, featuring advanced code understanding and tool execution capabilities.

2. Aider:

A command-line chat tool that can integrate with various LLMs (such as GPT-4o or Claude 3.5 Sonnet) and boasts high customizability as a fully open-source project.

3. GitHub Copilot CLI:

The official CLI tool from GitHub, capable of operating in close integration with the GitHub ecosystem.

4. Ollama + open-webui:

A solution that runs LLMs in a completely local environment, allowing you to manage your privacy 100% on your own.

Conclusion

The Go-based agy has a fast startup speed and is packed with features that enhance development efficiency, such as asynchronous parallel processing. Conversely, it is surprising that Gemini did not even support sub-agents until now, but this is a great opportunity to migrate to agy (the command name for Antigravity).

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