Open Food Facts MCP Server

Instructions

Implementation Reference

• src/handlers.ts:63-87 (handler)

  The main handler function that fetches the product data using OpenFoodFactsClient and generates nutritional analysis by calling the private analyzeNutrition method, returning formatted text content.

  async handleAnalyzeProduct(barcode: string) {
    const response = await this.client.getProduct(barcode);
    
    if (response.status === 0 || !response.product) {
      return {
        content: [
          {
            type: "text" as const,
            text: `Product not found for barcode: ${barcode}`,
          },
        ],
      };
    }
  
    const analysis = this.analyzeNutrition(response.product);
  
    return {
      content: [
        {
          type: "text" as const,
          text: analysis,
        },
      ],
    };
  }

• src/tools.ts:68-81 (schema)

  Tool schema definition in the tools array, specifying the name, description, and input schema that requires a 'barcode' string.

  {
    name: "analyze_product",
    description: "Get nutritional analysis and scores for a product by barcode",
    inputSchema: {
      type: "object",
      properties: {
        barcode: {
          type: "string",
          description: "The barcode/ID of the product to analyze",
        },
      },
      required: ["barcode"],
    },
  },

• src/index.ts:51-52 (registration)

  Registration in the MCP server's CallToolRequestHandler switch statement, dispatching 'analyze_product' tool calls to handlers.handleAnalyzeProduct with the barcode argument.

  case 'analyze_product':
    return await handlers.handleAnalyzeProduct(args.barcode);

• src/handlers.ts:212-248 (helper)

  Core helper method implementing the nutritional analysis logic, interpreting Nutri-Score, NOVA, Eco-Score, and breaking down key nutriments with qualitative assessments.

  private analyzeNutrition(product: Product): string {
    const sections = [`**Nutritional Analysis: ${product.product_name || 'Unknown Product'}**\n`];
    
    // Scores interpretation
    const scoreAnalysis = [];
    if (product.nutriscore_grade) {
      const grade = product.nutriscore_grade.toUpperCase();
      const gradeDesc = this.getNutriscoreDescription(grade);
      scoreAnalysis.push(`• Nutri-Score ${grade}: ${gradeDesc}`);
    }
    
    if (product.nova_group) {
      const group = String(product.nova_group);
      const groupDesc = this.getNovaDescription(group);
      scoreAnalysis.push(`• NOVA Group ${group}: ${groupDesc}`);
    }
    
    if (product.ecoscore_grade) {
      const grade = product.ecoscore_grade.toUpperCase();
      const gradeDesc = this.getEcoscoreDescription(grade);
      scoreAnalysis.push(`• Eco-Score ${grade}: ${gradeDesc}`);
    }
    
    if (scoreAnalysis.length > 0) {
      sections.push(`**Scores:**\n${scoreAnalysis.join('\n')}\n`);
    }
    
    // Detailed nutrition
    if (product.nutriments) {
      const nutrition = this.analyzeNutriments(product.nutriments);
      if (nutrition) {
        sections.push(`**Nutritional Breakdown:**\n${nutrition}\n`);
      }
    }
    
    return sections.join('\n');
  }