generate_image
Create images from text descriptions using Volcengine's AI technology, with customizable parameters for size, style, and output format.
Instructions
Generate images using Volcengine's text-to-image API
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| prompt | Yes | Text prompt for image generation (max 1000 characters) | |
| model | No | Model to use for image generation | doubao-seedream-3-0-t2i-250415 |
| size | No | Image size dimensions | 1024x1024 |
| seed | No | Random seed for reproducible results (-1 for random) | |
| guidance_scale | No | How closely to follow the prompt (1-10) | |
| watermark | No | Whether to add watermark to generated images | |
| response_format | No | Format for returned image data | url |
Implementation Reference
- src/tools.ts:28-59 (handler)The primary handler function for the 'generate_image' tool. Validates input arguments using Zod schema, prepares the request, calls the Volcengine API, and returns formatted success/error response.async generateImage(args: VolcengineImageGenerationToolArgs) { try { const validatedArgs = generateImageSchema.parse(args); const request = { model: validatedArgs.model, prompt: validatedArgs.prompt, response_format: validatedArgs.response_format, size: validatedArgs.size, seed: validatedArgs.seed, guidance_scale: validatedArgs.guidance_scale, watermark: validatedArgs.watermark, }; const response = await this.api.generateImage(request); return { success: true, data: { model: response.model, created: response.created, images: response.data, usage: response.usage, }, }; } catch (error) { return { success: false, error: error instanceof Error ? error.message : 'Unknown error occurred', }; } }
- src/tools.ts:11-19 (schema)Zod schema used for input validation of the 'generate_image' tool arguments.export const generateImageSchema = z.object({ prompt: z.string().min(1, 'Prompt is required').max(1000, 'Prompt too long'), model: z.string().default(DEFAULT_MODEL), size: z.enum(SUPPORTED_SIZES).default(DEFAULT_SIZE), seed: z.number().int().min(-1).max(2147483647).optional(), guidance_scale: z.number().min(1).max(10).optional(), watermark: z.boolean().default(true), response_format: z.enum(['url', 'b64_json']).default(DEFAULT_RESPONSE_FORMAT), });
- src/tools.ts:61-110 (registration)Tool definition method returning the MCP tool specification for 'generate_image', including name, description, and input schema. Used in listTools response.getToolDefinition() { return { name: 'generate_image', description: 'Generate images using Volcengine\'s text-to-image API', inputSchema: { type: 'object', properties: { prompt: { type: 'string', description: 'Text prompt for image generation (max 1000 characters)', }, model: { type: 'string', description: 'Model to use for image generation', default: DEFAULT_MODEL, }, size: { type: 'string', description: 'Image size dimensions', enum: SUPPORTED_SIZES, default: DEFAULT_SIZE, }, seed: { type: 'number', description: 'Random seed for reproducible results (-1 for random)', minimum: -1, maximum: 2147483647, }, guidance_scale: { type: 'number', description: 'How closely to follow the prompt (1-10)', minimum: 1, maximum: 10, }, watermark: { type: 'boolean', description: 'Whether to add watermark to generated images', default: true, }, response_format: { type: 'string', description: 'Format for returned image data', enum: ['url', 'b64_json'], default: DEFAULT_RESPONSE_FORMAT, }, }, required: ['prompt'], }, }; }
- src/index.ts:47-82 (registration)Dispatch logic in MCP callTool request handler: checks for 'generate_image' tool name and invokes the handler, formats MCP response.if (name === 'generate_image') { try { const result = await this.imageTools.generateImage(args); if (result.success) { return { content: [ { type: 'text', text: JSON.stringify(result.data, null, 2), }, ], }; } else { return { content: [ { type: 'text', text: `Error: ${result.error}`, }, ], isError: true, }; } } catch (error) { return { content: [ { type: 'text', text: `Error: ${error instanceof Error ? error.message : 'Unknown error'}`, }, ], isError: true, }; } }
- src/volcengine-api.ts:25-51 (helper)Low-level helper that makes the HTTP POST request to Volcengine's image generation API endpoint.async generateImage(request: VolcengineImageGenerationRequest): Promise<VolcengineImageGenerationResponse> { try { const response = await this.client.post<VolcengineImageGenerationResponse>( '/images/generations', request ); return response.data; } catch (error) { if (axios.isAxiosError(error)) { const status = error.response?.status; const message = error.response?.data?.error?.message || error.message; if (status === 401) { throw new Error('Invalid API key or unauthorized access'); } else if (status === 429) { throw new Error('Rate limit exceeded. Please try again later.'); } else if (status === 400) { throw new Error(`Invalid request: ${message}`); } else { throw new Error(`API request failed: ${message}`); } } throw new Error(`Unknown error: ${error instanceof Error ? error.message : 'Unknown error'}`); } }