- Check this notice before you install Gemini CLI
- What Gemini CLI is
- How to install Gemini CLI, as the README describes
- How to start Gemini CLI
- Signing in to Gemini CLI safely
- Reviewing what Gemini CLI wants to do
- When Gemini CLI makes sense for a small business
- A cautious first session with Gemini CLI
- What people confuse Gemini CLI with
- Frequently asked questions
To use Gemini CLI, install it with one of the README's routes, such as npm, open a terminal in your project folder and type gemini. First read the README notices: they say Antigravity CLI replaced it for free-tier and Google One users, and that it isn't optimized for Gemini 4 Argon.
Gemini CLI is a tool for people who are comfortable in a terminal, and I know that isn't most of my readers. But more freelancers and small business owners are asking about it, usually because a developer or an AI guide mentioned it. Before you install anything, you should know about a notice at the top of its README, so I'll start there.
Check this notice before you install Gemini CLI
The project's README on GitHub carries two notices. The first says that Gemini CLI was replaced by Antigravity CLI on June 18th, 2026 for free-tier and Google One users. The second says Gemini CLI has not been optimized for Gemini 4 Argon, and tells people who want that model to use Antigravity instead.
In plain words, which tool you should use depends on your account, and the README is the place to check. I'd read those notices first, and follow the README's link to Google's own explanation before installing.
What Gemini CLI is
The README describes Gemini CLI as an open-source AI agent that brings Gemini into your terminal, under the Apache License 2.0. A terminal is the text window where you type commands instead of clicking. Gemini CLI lets you describe a job in plain English there, such as explaining a codebase, and it can work with files in the folder you open it in.
The README lists uses like querying and editing large codebases, building apps from PDFs, images or sketches, debugging in natural language, and automating tasks such as pull request queries. It can also connect to extra capabilities through MCP servers.
How to install Gemini CLI, as the README describes
The README lists several ways to install it. These are copied as written there, so check the README for the current commands before you run them:
- Run it without installing, with npx: npx @google/gemini-cli
- Install it globally with npm: npm install -g @google/gemini-cli
- On macOS or Linux with Homebrew: brew install gemini-cli
- On macOS with MacPorts: sudo port install gemini-cli
The README also describes release channels for preview, stable and nightly versions. If you're not a developer, stable is the one that makes sense. The README page I read didn't state which version of Node.js you need and sends you to the installation docs for system requirements.
How to start Gemini CLI
- Open your terminal and move into the folder you want to work in.
- Type gemini and press Enter to start an interactive session in that folder.
- Sign in or set up access when you're asked (see the next section).
- Type what you want in plain English and read what it proposes before you approve anything.
The README also describes a non-interactive mode, where you add the -p option and a prompt to run a single request and print the answer. That's handy for scripts.
Signing in to Gemini CLI safely
The README lists three routes: signing in with your Google account, using a Gemini API key, and an organisation route through Google Cloud. It uses environment variables for the key and project settings.
- Never paste an API key into a prompt, a chat, a shared document or a file you commit to GitHub.
- Keep keys in environment variables or a secrets manager, as the README shows, and never in the code.
- If a key leaks, delete it in your Google account and create a new one.
Reviewing what Gemini CLI wants to do
A command-line agent can read and change files and run commands, so treat it like a new team member on its first day. Read each suggested change before you accept it, work in a copy of your project, and keep a backup. The README says the docs cover sandboxed execution and Trusted Folders, which control what the tool is allowed to run in each folder, and that the project publishes a security policy. Use those features.
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And review any code it writes before you run it. AI-written code can look right and still contain mistakes, or do more than you expected.
When Gemini CLI makes sense for a small business
- You have a developer or a technical freelancer who already works in the terminal.
- You want to understand a website's code, or a script someone wrote for you.
- You'd like help with repetitive file jobs, such as renaming or tidying a batch of documents.
If you're not technical, you'll probably get more from Gemini in the app, and my beginner guide to using Gemini is a gentler start. If you want help deciding what to automate, that's a conversation to have with an AI consultant.
A cautious first session with Gemini CLI
If you do go ahead, start small. Make a copy of a harmless folder, such as a handful of text files, open the terminal there and ask Gemini CLI to explain what's in it. That gets you used to how it asks permission and shows you what it can see. Only once you're comfortable should you point it at anything that matters.
- Keep a backup before any session that can change files.
- Read every command it proposes to run, and say no to anything you don't understand.
- Stop and check the README again if a notice, a command or a sign-in screen looks different from what you expected.
Developer tools change faster than most software, and the README is the one place that's kept up to date by the people who maintain it. If this page and the README disagree, trust the README.
What people confuse Gemini CLI with
| Name | What it covers |
|---|---|
| Gemini CLI | An open-source command-line agent for developers, per its README |
| Antigravity CLI | The tool the README says replaced Gemini CLI for free-tier and Google One users |
| Gemini app | The chat app for phone and web, with no terminal involved |
| Gemini API | The developer interface behind many tools, accessed with a key |
Frequently asked questions
What is Gemini CLI?
The README describes it as an open-source AI agent that brings Gemini into your terminal, under the Apache License 2.0.
How do I install Gemini CLI?
The README lists npx, a global npm install, Homebrew and MacPorts. Check the README for the current commands.
Has Gemini CLI been replaced?
The README says Gemini CLI was replaced by Antigravity CLI on June 18th, 2026 for free-tier and Google One users. Read the notice to see which applies to you.
How do I start Gemini CLI?
Open a terminal in your project folder and type gemini. For one-off prompts, the README describes a non-interactive mode with the -p option.
Is it safe to use?
Review its suggestions and any code before running them, work in a copy, use the sandbox and Trusted Folders features the docs describe, and never paste API keys into prompts.
