Gemini CLI Extensions: Bringing Nano Banana to Your Terminal

Google’s Gemini CLI just got a massive upgrade — the Extensions feature has unlocked its full potential.

These extensions let you integrate your favorite third-party tools and services directly into your AI workflow. In other words, you can now do things in the terminal — like drawing architecture diagrams or deploying projects — that previously required opening multiple apps.

Let’s dive in.

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🚀 The Basics of Gemini CLI

Before we get into extensions, let’s briefly cover what Gemini CLI can do out of the box.

• Built-in Gemini Models – It integrates Google’s Gemini models, offering strong reasoning and generation capabilities.

• Developer Assistance – It can write, debug, and refactor code, or even generate a README based on your project files.

• Built-in Tools – Gemini CLI can call essential tools by itself, such as:

  • Google Search: Fetch the latest web information.

  • File Operations: Read or write files in your project.

  • Shell Commands: Execute commands like ls or grep.

• Project Context: You can add a GEMINI.md file in your project to describe background, coding standards, and other details — the AI will tailor its responses accordingly.

Gemini CLI’s free plan supports 60 requests per minute and 1,000 requests per day. The Gemini 2.5 Pro version also offers a 1 million token context window, meaning you can feed an entire project’s codebase into it for deep context understanding.

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⚙️ How to Install Gemini CLI

Gemini CLI requires Node.js 20 or above — this is also necessary for installing extensions later.

You can use ServBay to quickly set up the required Node.js environment and other development tools with one click.

1. Download and install ServBay.

2. In the left menu, go to Packages, select Node.js, and click to install your desired version. (Make sure to choose version 20 or higher.)

3. Once installed, open the terminal and verify the setup with node -v.

✅ Now your environment is ready.

To install Gemini CLI, just run:

npx https://github.com/google-gemini/gemini-cli

Then follow the prompts:

• Pick your preferred theme color.

• Sign in with your Google account.

You’re done — the entire process takes less than 5 minutes.

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🔌 What Are Extensions?

Extensions are plugins for Gemini CLI. Installing one teaches the CLI how to use a new external tool.

For example, by installing a diagram tool extension, you can simply say:

“Generate a user login architecture diagram.”

…and Gemini CLI will call that tool and complete the task directly from your terminal — no app-switching needed.

You can use public extensions or create your own. If your team has internal tools or a fixed automation pipeline (e.g., packaging, deployment, notifications), you can bundle them into an extension so anyone on your team can trigger it with one command.

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🧩 Example: Creating a Diagram with the Nano Banana Extension

Let’s go through a practical example using Nano Banana, one of the most popular extensions recently added to Gemini CLI.

Step 1: Find and Install the Extension

Go to the Gemini CLI Extension Gallery, search for Nano Banana, and follow the GitHub link.

Before installing, ensure that:

• You have Node.js 20+

• npm is available (it’s installed automatically with Node.js if you used ServBay)

Install the extension by running:

gemini extensions install https://github.com/gemini-cli-extensions/nanobanana

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Step 2: Configure and Verify

1. Set Your API Key: Nano Banana uses an API key — you can reuse your existing Gemini API key.

   export NANOBANANA_GEMINI_API_KEY="your_gemini_api_key"

1. Restart Gemini CLI and check whether the extension was successfully added:

   /extensions list

If you see nanobanana listed, everything is ready to go.

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Step 3: Generate Your First Architecture Diagram

Use the /diagram command:

/diagram "Generate a technical architecture diagram for an AI agent." --type="architecture" --complexity="simple"

Approve the permissions when prompted, and wait a few seconds — a fully generated AI architecture diagram will appear.

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Step 4: Refine Using Natural Language

If the first result looks messy, just ask Gemini CLI to fix it:

“Make it more professional, aligned, and consistent in font style.”

It will understand and regenerate a cleaner version — you can iterate this process until you’re satisfied.

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🧠 Final Thoughts

The Gemini CLI’s extension system turns it from a simple AI chat tool into a powerful command-line hub that can integrate dozens of developer workflows — from diagramming to deployment.

And with ServBay, setting up your Node.js 20+ environment and other tools becomes effortless — it’s the easiest way to deploy your dev environment with one click.

Gemini CLI + ServBay = A developer’s dream workflow.

Try it out and see how seamless your terminal life can become.