doubao-i2i-generator-mcp/mcp_server.js

MCP Server for generating images using Doubao Seedream 3.0 i2i (image-to-image) model

#!/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 { spawn } from 'child_process';
 

// 创建MCP服务器
const server = new Server({
  name: 'doubao-i2i-generator',
  version: '1.0.0',
});

// 列出可用工具
server.setRequestHandler(ListToolsRequestSchema, async () => {
  return {
    tools: [
      {
        name: 'generate_i2i_image',
        description: '使用豆包Seedream-3 i2i模型，根据文字提示和输入图片生成新图片',
        inputSchema: {
          type: 'object',
          properties: {
            model: { type: 'string', description: '模型ID', default: 'doubao-seededit-3-0-i2i-250628' },
            prompt: { type: 'string', description: '文字提示词，描述想要生成的图片效果' },
            image: { type: 'string', description: '输入图片的URL地址' },
            response_format: { type: 'string', description: '输出格式：url 或 b64_json', default: 'url' },
            size: { type: 'string', description: '图像尺寸', default: 'adaptive' },
            seed: { type: 'number', description: '随机种子，用于控制生成结果的一致性', default: 21 },
            guidance_scale: { type: 'number', description: '引导强度，控制生成图片与提示词的匹配程度', default: 5.5 },
            watermark: { type: 'boolean', description: '是否添加水印', default: true }
          },
          required: ['prompt', 'image']
        }
      }
    ]
  };
});

// 处理工具调用
server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;

  try {
    let result;
    
    switch (name) {
      case 'generate_i2i_image':
        result = await generateI2IImage(args);
        break;
      default:
        result = `未知工具: ${name}`;
    }

    return { content: [{ type: 'text', text: typeof result === 'string' ? result : JSON.stringify(result) }] };
  } catch (error) {
    return {
      content: [
        {
          type: 'text',
          text: `执行错误: ${error.message}`
        }
      ]
    };
  }
});

// i2i图片生成工具：根据文字提示和输入图片生成新图片
async function generateI2IImage({ 
  model = 'doubao-seededit-3-0-i2i-250628', 
  prompt, 
  image, 
  response_format = 'url', 
  size = 'adaptive', 
  seed = 21, 
  guidance_scale = 5.5, 
  watermark = true 
}) {
  const apiKey = process.env.ARK_API_KEY;
  if (!apiKey) {
    throw new Error('请设置 ARK_API_KEY');
  }
  const baseUrl = (process.env.ARK_BASE_URL || 'https://ark.cn-beijing.volces.com/api/v3').replace(/\/+$/,'');

  const payload = {
    model,
    prompt,
    image,
    response_format,
    size,
    seed,
    guidance_scale,
    watermark
  };

  return new Promise((resolve, reject) => {
    const hasFullEndpoint = /\/images\/generations$/.test(baseUrl);
    const endpoint = hasFullEndpoint ? baseUrl : `${baseUrl}/images/generations`;
    const args = [
      '-sS',
      '-X', 'POST', endpoint,
      '-H', 'Content-Type: application/json',
      '-H', `Authorization: Bearer ${apiKey}`,
      '-d', JSON.stringify(payload)
    ];

    const proc = spawn('curl', args, { stdio: ['ignore', 'pipe', 'pipe'] });
    let stdout = '';
    let stderr = '';
    proc.stdout.on('data', (d) => { stdout += d.toString(); });
    proc.stderr.on('data', (d) => { stderr += d.toString(); });
    proc.on('close', (code) => {
      if (code !== 0) {
        return reject(new Error(`curl 执行失败，退出码 ${code}, 错误: ${stderr || '无'}`));
      }
      try {
        const json = JSON.parse(stdout);
        resolve(json);
      } catch (e) {
        reject(new Error(`解析响应失败: ${e.message}; 原始输出: ${stdout}`));
      }
    });
    proc.on('error', (err) => reject(new Error(`启动curl失败: ${err.message}`)));
  });
}

// 启动服务器
async function main() {
  const transport = new StdioServerTransport();
  await server.connect(transport);
  console.error('Doubao I2I Image Generator MCP Server started');
}

main().catch(console.error);