#!/usr/bin/env node
import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
import {
CallToolRequestSchema,
ListToolsRequestSchema,
} from '@modelcontextprotocol/sdk/types.js';
import { GeminiImageGenerator } from './gemini.js';
import { loadConfig } from './config.js';
import type { ImageGenerationParams, AspectRatio, ImageSize } from './types.js';
const config = loadConfig();
// Validate API key
const apiKey = process.env.GEMINI_API_KEY;
if (!apiKey) {
console.error('Error: GEMINI_API_KEY environment variable is required');
process.exit(1);
}
// Initialize Gemini client
const generator = new GeminiImageGenerator(
apiKey,
config.model,
config.outputDirectory
);
// Create MCP server
const server = new Server(
{
name: 'mcp-image-gen',
version: '1.0.0',
},
{
capabilities: {
tools: {},
},
}
);
// List available tools
server.setRequestHandler(ListToolsRequestSchema, async () => {
return {
tools: [
{
name: 'generate_image',
description: `Generate an image using Google Gemini AI (${config.model}). Creates high-quality images from text prompts with customizable aspect ratios and sizes. Images are saved to ${config.outputDirectory}.`,
inputSchema: {
type: 'object',
properties: {
prompt: {
type: 'string',
description: 'Text description of the image to generate. Be detailed and specific for best results.',
},
aspectRatio: {
type: 'string',
enum: ['1:1', '2:3', '3:2', '3:4', '4:3', '4:5', '5:4', '9:16', '16:9', '21:9'],
description: `Aspect ratio of the generated image. Default: ${config.defaultAspectRatio}`,
default: config.defaultAspectRatio,
},
imageSize: {
type: 'string',
enum: ['small', 'medium', 'large', 'xlarge'],
description: `Image resolution (small: 1K, medium: 2K, large: 2K, xlarge: 4K). Note: gemini-2.5-flash-image only supports 1K. Default: ${config.defaultImageSize}`,
default: config.defaultImageSize,
},
negativePrompt: {
type: 'string',
description: 'Optional. Describe what you do NOT want in the image.',
},
},
required: ['prompt'],
},
},
],
};
});
// Handle tool calls
server.setRequestHandler(CallToolRequestSchema, async (request) => {
if (request.params.name === 'generate_image') {
try {
const args = request.params.arguments || {};
if (!args || typeof args !== 'object' || !('prompt' in args) || typeof args.prompt !== 'string') {
throw new Error('Invalid arguments: prompt is required and must be a string');
}
// Apply defaults from config
const finalParams: ImageGenerationParams = {
prompt: args.prompt,
aspectRatio: (args.aspectRatio as AspectRatio) || config.defaultAspectRatio,
imageSize: (args.imageSize as ImageSize) || config.defaultImageSize,
negativePrompt: args.negativePrompt as string | undefined,
};
const result = await generator.generateImage(finalParams);
return {
content: [
{
type: 'text',
text: JSON.stringify(
{
success: true,
imagePath: result.imagePath,
prompt: result.prompt,
model: result.model,
aspectRatio: result.aspectRatio,
imageSize: result.imageSize,
message: `Image generated successfully and saved to: ${result.imagePath}`,
},
null,
2
),
},
],
};
} catch (error) {
const errorMessage = error instanceof Error ? error.message : 'Unknown error';
return {
content: [
{
type: 'text',
text: JSON.stringify(
{
success: false,
error: errorMessage,
},
null,
2
),
},
],
isError: true,
};
}
}
throw new Error(`Unknown tool: ${request.params.name}`);
});
// Start server
async function main() {
const transport = new StdioServerTransport();
await server.connect(transport);
console.error('MCP Image Gen Server running on stdio');
console.error(`Model: ${config.model}`);
console.error(`Output Directory: ${config.outputDirectory}`);
}
main().catch((error) => {
console.error('Fatal error:', error);
process.exit(1);
});
