@nanobanana/mcp 🍌

A lean MCP server for Google's Nano Banana (Gemini) image models. It generates and edits images from any MCP client (Claude Code, Claude Desktop, Cursor) and hands back file paths instead of base64, so your agent's context stays small.

• Three tools and nothing else: generate_image, edit_image, list_models
• Defaults to Nano Banana 2 (gemini-3.1-flash-image). Switch models per call or via env. If a pinned model id ever goes stale, list_models shows what your key can actually use.
• Multi-image editing: pass reference images for style transfer, characters, or compositing
• Control over aspect ratio (1:1 up to 21:9) and resolution (1K, 2K, 4K)
• Google Search grounding for images that need real-world accuracy, like infographics
• Safe output paths. The server never writes to / when a desktop MCP client spawns it there.
• Auth lives in env vars only, so your API key never passes through chat context

Quick start

Get a free Gemini API key at aistudio.google.com/apikey.

Claude Code

claude mcp add nanobanana -e GEMINI_API_KEY=your_key -- npx -y @nanobanana/mcp

Also listed in the MCP Registry as io.github.getjoystick/nanobanana-mcp.

Claude Desktop / Cursor: add this to claude_desktop_config.json or .cursor/mcp.json:

{
  "mcpServers": {
    "nanobanana": {
      "command": "npx",
      "args": ["-y", "@nanobanana/mcp"],
      "env": { "GEMINI_API_KEY": "your_key" }
    }
  }
}

Tools

generate_image

| Param | Required | Description | |---|---|---| | prompt | ✅ | Image description | | model | | Gemini image model id (default gemini-3.1-flash-image) | | aspectRatio | | 1:1, 16:9, 9:16, 4:3, 21:9, and similar | | size | | 1K, 2K, or 4K | | grounding | | Ground with Google Search for factual accuracy | | outputDir | | Save directory (default ./nano-banana) | | filename | | Base filename without extension |

edit_image

Same params, plus:

| Param | Required | Description | |---|---|---| | images | ✅ | Input image path(s). The first is the base; the rest are references. |

Both tools save to disk and return the file path.

list_models

Takes no params. Lists the image model ids your API key can use. Handy when a pinned model id stops working, which is how earlier Nano Banana servers broke.

Configuration

| Env var | Description | |---|---| | GEMINI_API_KEY | Required. Gemini API key (GOOGLE_API_KEY also works) | | NANOBANANA_MODEL | Default model override | | NANOBANANA_OUTPUT_DIR | Default output directory override |

Models

| Model id | Notes | |---|---| | gemini-3.1-flash-image | Default. Nano Banana 2: 4K output, strong text rendering | | gemini-3-pro-image | Nano Banana Pro, for complex scenes that need deeper reasoning | | gemini-2.5-flash-image | The original Nano Banana (legacy; Google retires it 2026-10-02) |

Development

npm install
npm run build
GEMINI_API_KEY=your_key npm run smoke   # end-to-end test against the live API

Acknowledgements

Inspired by other Nano Banana MCPs. Built with Claude Code.

License

MIT