OpenRouter Image MCP Server

Instructions

Implementation Reference

• src/tools/analyze-image.ts:7-112 (handler)

  Main handler function for the 'analyze_image' tool. Processes input arguments, handles image processing with timeouts, validation, and delegates to OpenRouterClient for analysis.
  export async function handleAnalyzeImage( args: any, config: Config, openRouterClient: OpenRouterClient, logger: Logger ) { const imageProcessor = ImageProcessor.getInstance(); try { const imageInput: ImageInput = { type: args.type as 'base64' | 'file' | 'url', data: args.data as string, mimeType: args.mimeType as string, }; const options: ImageAnalysisOptions = { prompt: args.prompt as string, format: args.format as 'text' | 'json', maxTokens: args.maxTokens as number, temperature: args.temperature as number, }; logger.info(`Starting image analysis for type: ${imageInput.type}`); // Add timeout for image processing (30 seconds) const processTimeoutPromise = new Promise((_, reject) => { setTimeout(() => reject(new Error('Image processing timed out after 30 seconds')), 30000); }); // Process the image with timeout const processedImage = await Promise.race([ imageProcessor.processImage(imageInput), processTimeoutPromise ]) as { data: string; mimeType: string; size: number }; // Validate image type if (!imageProcessor.isValidImageType(processedImage.mimeType)) { throw new Error(`Unsupported image type: ${processedImage.mimeType}`); } // Check file size const serverConfig = config.getServerConfig(); const maxImageSize = serverConfig.maxImageSize || 10485760; if (processedImage.size > maxImageSize) { throw new Error(`Image size ${processedImage.size} exceeds maximum allowed size ${maxImageSize}`); } // Add timeout for the API call (120 seconds) const apiTimeoutPromise = new Promise<never>((_, reject) => { setTimeout(() => reject(new Error('Image analysis timed out after 2 minutes')), 120000); }); // Analyze the image with timeout const analysisPromise = openRouterClient.analyzeImage( processedImage.data, processedImage.mimeType, options.prompt || 'Analyze this image in detail. Describe what you see, including objects, people, text, and any notable features.', options ); const result = await Promise.race([analysisPromise, apiTimeoutPromise]); if (!result.success) { throw new Error(result.error || 'Failed to analyze image'); } logger.info(`Image analysis completed successfully`, { model: result.model, usage: result.usage, }); return { content: [ { type: 'text', text: result.analysis || 'No analysis available', }, ], }; } catch (error) { logger.error('Image analysis failed', error); // Check if it's a timeout error if (error instanceof Error && error.message.includes('timed out')) { return { content: [ { type: 'text', text: `Error: ${error.message}. The image may be too large or the server is experiencing delays.`, }, ], isError: true, }; } return { content: [ { type: 'text', text: `Error: ${(error as Error).message}`, }, ], isError: true, }; } }
• src/index.ts:48-89 (schema)

  Tool schema definition for 'analyze_image' including input schema, properties, and requirements, provided in the ListTools response.
  { name: 'analyze_image', description: 'Analyze images using OpenRouter\'s vision models. Supports various input formats including base64, file paths, and URLs.', inputSchema: { type: 'object', properties: { type: { type: 'string', enum: ['base64', 'file', 'url'], description: 'The type of image input', }, data: { type: 'string', description: 'The image data (base64 string, file path, or URL)', }, mimeType: { type: 'string', description: 'MIME type of the image (required for base64 input)', }, prompt: { type: 'string', description: 'Custom prompt for image analysis (optional)', }, format: { type: 'string', enum: ['text', 'json'], description: 'Output format (default: text)', }, maxTokens: { type: 'number', description: 'Maximum tokens in response (default: 4000)', }, temperature: { type: 'number', minimum: 0, maximum: 2, description: 'Sampling temperature (default: 0.1)', }, }, required: ['type', 'data'], }, },
• src/index.ts:192-193 (registration)

  Registration of the handler in the centralized CallToolRequestHandler switch statement.
  case 'analyze_image': return await handleAnalyzeImage(args, config, openRouterClient, logger);
• src/utils/openrouter-client.ts:81-201 (helper)

  Core helper method in OpenRouterClient that performs the actual image analysis API request to OpenRouter's chat completions endpoint with vision support.
  public async analyzeImage( imageData: string, mimeType: string, prompt: string, options: { format?: 'text' | 'json'; maxTokens?: number; temperature?: number; } = {} ): Promise<ImageAnalysisResult> { try { this.logger.debug(`Analyzing image with model: ${this.config.model}`); // Validate inputs if (!imageData || imageData.length === 0) { throw new Error('No image data provided'); } if (!mimeType) { throw new Error('No MIME type provided'); } // Check image data size (base64 encoded) if (imageData.length > 20 * 1024 * 1024) { // 20MB base64 limit throw new Error(`Image data too large: ${imageData.length} characters. Maximum allowed is 20MB.`); } // Validate prompt length const promptText = prompt || 'Analyze this image in detail. Describe what you see, including objects, people, text, and any notable features.'; if (promptText.length > 10000) { throw new Error(`Prompt too long: ${promptText.length} characters. Maximum allowed is 10000.`); } const requestBody = { model: this.config.model, messages: [ { role: 'user', content: [ { type: 'text', text: promptText, }, { type: 'image_url', image_url: { url: `data:${mimeType};base64,${imageData}`, }, }, ], }, ], max_tokens: Math.min(options.maxTokens || 4000, 8000), // Cap at 8000 tokens temperature: options.temperature || 0.1, response_format: options.format === 'json' ? { type: 'json_object' } : undefined, }; this.logger.debug(`Sending request to OpenRouter API`, { model: this.config.model, imageSize: imageData.length, promptLength: promptText.length, maxTokens: requestBody.max_tokens, }); const response = await this.client.post('/chat/completions', requestBody); const choice = response.data.choices?.[0]; if (!choice) { throw new Error('No response from model'); } const content = choice.message?.content; if (!content) { throw new Error('Empty response from model'); } let analysis: string; let structuredData: any; if (options.format === 'json') { try { structuredData = JSON.parse(content); analysis = JSON.stringify(structuredData, null, 2); } catch { // If JSON parsing fails, treat as text analysis = content; structuredData = { analysis: content }; } } else { analysis = content; structuredData = { analysis }; } const usage = response.data.usage; this.logger.info(`Image analysis completed successfully`, { model: this.config.model, usage, }); return { success: true, analysis, structuredData, model: this.config.model, usage: usage ? { promptTokens: usage.prompt_tokens, completionTokens: usage.completion_tokens, totalTokens: usage.total_tokens, } : undefined, }; } catch (error) { this.logger.error('Failed to analyze image', error); const errorMessage = this.extractErrorMessage(error); return { success: false, error: errorMessage, }; } }