generateImage

Implementation Reference

• src/index.ts:25-69 (registration)

  The tool 'generateImage' is registered via server.tool() on the McpServer instance. This is the registration point that binds the name, schema, and handler together.

  server.tool(
    'generateImage',
    {
      outputPathAbsolute: z.string().describe('The absolute path where the image should be written out.'),
      prompt: z.string().describe("Text description of the desired image content"),
      quality: z.enum(["auto", "low", "medium", "high"]).optional().describe("The quality of the image."),
      size: z.enum(['1024x1024', '1024x1536', '1536x1024', 'auto']).optional().describe("Size of the generated image"),
    },
    async ({ prompt, size = "1024x1024", quality="low", outputPathAbsolute}) => {
      try {
        const response = await openai.images.generate({
          model: "gpt-image-1",
          prompt,
          n: 1,
          size: size,
          quality: quality,
        });
  
        if (!response.data) {
          throw new Error(`API did not return any data.`);
        }
  
        if (!response.data[0]?.b64_json) {
          throw new Error('API did not return image data');
        }
        
        const imageData = response.data[0].b64_json;
        const bytes = Buffer.from(imageData, 'base64');
  
        writeFileSync(outputPathAbsolute, bytes)
  
        return {
          content: [
              {
                  type: 'text',
                  text: `The image is now available at ${outputPathAbsolute}.`
              }
          ],
          message: "Image generated successfully!"
        };
      } catch (error) {
        throw new Error(`Error generating image: ${JSON.stringify(error, null, 2)}`, {cause: error});
      }
    }
  );

• src/index.ts:27-32 (schema)

  Zod schema definitions for the 'generateImage' tool inputs: outputPathAbsolute (string), prompt (string), quality (enum: auto/low/medium/high, optional), size (enum: 1024x1024/1024x1536/1536x1024/auto, optional).

  {
    outputPathAbsolute: z.string().describe('The absolute path where the image should be written out.'),
    prompt: z.string().describe("Text description of the desired image content"),
    quality: z.enum(["auto", "low", "medium", "high"]).optional().describe("The quality of the image."),
    size: z.enum(['1024x1024', '1024x1536', '1536x1024', 'auto']).optional().describe("Size of the generated image"),
  },

• src/index.ts:33-68 (handler)

  The async handler function that executes the tool logic. It calls OpenAI's images.generate API with the gpt-image-1 model, receives base64 image data, writes it to the specified output path, and returns a success message.

  async ({ prompt, size = "1024x1024", quality="low", outputPathAbsolute}) => {
    try {
      const response = await openai.images.generate({
        model: "gpt-image-1",
        prompt,
        n: 1,
        size: size,
        quality: quality,
      });
  
      if (!response.data) {
        throw new Error(`API did not return any data.`);
      }
  
      if (!response.data[0]?.b64_json) {
        throw new Error('API did not return image data');
      }
      
      const imageData = response.data[0].b64_json;
      const bytes = Buffer.from(imageData, 'base64');
  
      writeFileSync(outputPathAbsolute, bytes)
  
      return {
        content: [
            {
                type: 'text',
                text: `The image is now available at ${outputPathAbsolute}.`
            }
        ],
        message: "Image generated successfully!"
      };
    } catch (error) {
      throw new Error(`Error generating image: ${JSON.stringify(error, null, 2)}`, {cause: error});
    }
  }