Nano Banana Pro MCP Server

A minimal, auditable MCP server that gives Claude Desktop the ability to generate and edit images using Google's Nano Banana Pro (Gemini 3 Pro Image) model.

~150 lines of TypeScript. No hidden dependencies. You own the code.

What it does

Generated images are returned inline (so Claude can display them in chat) and saved to ~/nano-banana-output/.

Images are never written to local disk. Each is returned inline for viewing, and — when Firebase Storage is configured — uploaded there with a signed URL you can fetch from other environments (e.g. to embed in a document).

Related MCP server: Banana Image MCP

Prerequisites

• Node.js 18+ — check with node --version

• Gemini API key — free from Google AI Studio. Enable billing for image generation (pay-per-image, no monthly minimum).

Setup

1. Clone and build

git clone <your-repo-url> nano-banana-mcp
cd nano-banana-mcp
npm install
npm run build

2. Configure Claude Desktop

Open your Claude Desktop config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

Add this entry (adjust the path to where you cloned the repo):

{
  "mcpServers": {
    "nano-banana-pro": {
      "command": "node",
      "args": ["/absolute/path/to/nano-banana-mcp/build/index.js"],
      "env": {
        "GEMINI_API_KEY": "your-api-key-here"
      }
    }
  }
}

3. Restart Claude Desktop

The server should appear in the MCP tools menu (hammer icon).

Usage examples

Once connected, just ask Claude naturally:

• "Generate an image of a Senegalese market at sunset"

• "Create a 16:9 hero banner for a blog about climate resilience"

• "Edit ~/nano-banana-output/gen_20260714_a1b2.png — remove the background and add a gradient"

Models

The server supports two Gemini image models:

By default, generate_image uses Pro. Pass use_pro: false to switch to the faster Flash model.

Security notes

• Your API key stays local — it's passed via environment variable, never logged or transmitted elsewhere.

• The server only makes HTTPS calls to generativelanguage.googleapis.com (Google's Gemini API).

• No telemetry, no analytics, no third-party calls.

• All code is in src/index.ts — read it before you run it.

Project structure

nano-banana-mcp/
├── src/
│   └── index.ts      ← the entire server (~150 lines)
├── package.json
├── tsconfig.json
└── README.md

License

MIT — do whatever you want with it.

Optional: Firebase Storage (cross-environment image transfer)

By default, generated images are saved to ~/nano-banana-output/ on the machine running the MCP server. If you want images to be usable in another environment (e.g. embedding in a document built by Claude's sandbox) without manually attaching files, configure Firebase Storage. The server will upload each image and return a time-limited signed URL that the other environment can download directly.

Point at your service-account JSON key file (recommended):

"env": {
  "GEMINI_API_KEY": "[API_KEY]",
  "SERVICE_ACCOUNT_KEY_PATH": "/absolute/path/to/firebase-service-account.json",
  "FIREBASE_STORAGE_BUCKET": "your-project.appspot.com"
}

Download the JSON key from Firebase Console → Project Settings → Service Accounts → Generate new private key, save it somewhere on your machine, and point SERVICE_ACCOUNT_KEY_PATH at it.

Alternatively, supply the individual fields instead of a key file (FIREBASE_PROJECT_ID, FIREBASE_CLIENT_EMAIL, FIREBASE_PRIVATE_KEY, plus FIREBASE_STORAGE_BUCKET).

Optional: FIREBASE_SIGNED_URL_MINUTES (default 60) controls how long the download URL stays valid.

Notes:

• The service-account credentials stay in the MCP server process only — they are never sent to Claude or its sandbox. The sandbox only ever sees a plain signed URL.

• Get the service-account values from Firebase Console → Project Settings → Service Accounts → Generate new private key.

• If any of the four vars is missing, uploads stay disabled and the server falls back to saving locally.

• For the download to work, the environment fetching the URL must have outbound network access to storage.googleapis.com.