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# nanobanana-mcp
**An MCP server for builders who want to generate and edit images with Google Gemini from Claude Code or any other MCP client.**
A hardened MCP server for Gemini image generation. Fork of [ConechoAI/Nano-Banana-MCP](https://github.com/ConechoAI/Nano-Banana-MCP) with security fixes, strict TypeScript, and model selection.
[](package.json) [](LICENSE) [](https://nodejs.org)
[Get started](#quick-start) · [Tools](#tools) · [Configuration](#configuration) · [Security](#security) · [Report an issue](https://github.com/DojoCodingLabs/nanobanana-mcp/issues/new)
## Features
- **3 tools**: `generate_image`, `edit_image`, `continue_editing`
- **Model selection** via `NANOBANANA_MODEL` env var with whitelist validation
- **Security hardened**: path traversal protection, file size limits, no plaintext key storage
- **Strict TypeScript**: zero `any` types, Zod validation on all inputs
## Quick Start
### Claude Code
Add to `~/.claude/settings.json`:
```json
{
"mcpServers": {
"nanobanana": {
"command": "npx",
"args": ["tsx", "/path/to/nanobanana-mcp/src/index.ts"],
"env": {
"GEMINI_API_KEY": "your-api-key",
"NANOBANANA_MODEL": "gemini-2.5-flash-image"
}
}
}
}
```
### Other MCP Clients
```bash
GEMINI_API_KEY=your-key npx tsx src/index.ts
```
The server communicates over stdio using the MCP protocol.
## Tools
### `generate_image`
Generate a new image from a text prompt.
```
prompt (required): Text describing the image to create (max 10,000 chars)
```
### `edit_image`
Edit an existing image with a text prompt.
```
imagePath (required): Full file path to the image to edit
prompt (required): Text describing the modifications (max 10,000 chars)
referenceImages (optional): Array of file paths to reference images
```
### `continue_editing`
Continue editing the last generated/edited image in the current session.
```
prompt (required): Text describing changes to make (max 10,000 chars)
referenceImages (optional): Array of file paths to reference images
```
## Configuration
All configuration is via environment variables. No config files are written to disk.
| Variable | Required | Description |
|----------|----------|-------------|
| `GEMINI_API_KEY` | Yes | Google Gemini API key |
| `NANOBANANA_GEMINI_API_KEY` | No | Override for `GEMINI_API_KEY` (takes priority) |
| `NANOBANANA_MODEL` | No | Model to use (see below) |
### Available Models
| Model ID | Description |
|----------|-------------|
| `gemini-2.5-flash-image` | Fast generation, good for high-volume use (default) |
| `gemini-3-pro-image-preview` | Pro quality, complex prompts, better text rendering |
| `gemini-3.1-flash-image-preview` | Latest model, advanced features |
## Output
Generated images are saved to `~/nanobanana-images/` with unique filenames. The tool response includes both the file path and the image data inline.
## Security
This fork addresses the following security issues from the original:
| Issue | Fix |
|-------|-----|
| API key saved to disk in plaintext | Removed config file persistence entirely |
| `configure_gemini_token` tool accepts key via MCP | Tool removed; keys only via env vars |
| Path traversal in `editImage` | `validatePath()` checks paths resolve within `$HOME` or `$TMPDIR` |
| No prompt length validation | Capped at 10,000 chars via Zod |
| Hardcoded model | `NANOBANANA_MODEL` env var with whitelist |
| Silent swallowing of reference image errors | Errors now thrown and reported |
| `Math.random()` for filenames | `crypto.randomUUID()` |
| No file size limit on reads | Max 20MB |
| Verbose errors leak internal paths | Sanitized error messages |
| `process.cwd()` fallback for output dir | Fixed to `~/nanobanana-images/` |
## Development
```bash
npm install
npm run typecheck # Type check without emitting
npm run dev # Run with tsx (hot reload)
npm run build # Compile to dist/
```
## Project Structure
```
src/
index.ts # MCP server entry point (3 tool handlers)
gemini-client.ts # Gemini API wrapper with model selection
file-handler.ts # Secure file I/O with path validation
types.ts # TypeScript interfaces and Zod schemas
```
## License
[MIT](LICENSE) - Based on [ConechoAI/Nano-Banana-MCP](https://github.com/ConechoAI/Nano-Banana-MCP). Built by [Dojo Coding](https://dojocoding.io).
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