@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, 21:9, extremes up to 1:4 and 8:1
size		512, 1K, 2K, or 4K
grounding		Ground with Google Search for factual accuracy
thinkingLevel		minimal or high; high helps complex or text-heavy images
outputDir		Save directory (default ./nano-banana)
filename		Base filename without extension

edit_image

Same params, plus:

Param	Required	Description
images	✅	Input file path(s): png, jpg, webp, heic, or pdf. 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