Open Food Facts MCP Server

Instructions

Implementation Reference

• src/handlers.ts:116-154 (handler)

  Main handler function executing the tool: destructures params, builds search query for category and nutriscore, calls client.searchProducts, filters by dietary preferences, formats suggestions, returns formatted text response.

  async handleGetProductSuggestions(params: any) {
    const { category, dietary_preferences = [], max_results = 10, min_nutriscore } = params;
    
    const searchParams: any = {
      categories: category,
      page_size: Math.min(max_results * 2, 100), // Get extra to filter
      sort_by: 'popularity',
    };
  
    if (min_nutriscore) {
      const validGrades = ['a', 'b', 'c', 'd', 'e'];
      const minIndex = validGrades.indexOf(min_nutriscore);
      const allowedGrades = validGrades.slice(0, minIndex + 1);
      searchParams.nutrition_grades = allowedGrades.join(',');
    }
  
    const response = await this.client.searchProducts(searchParams);
    
    let filteredProducts = response.products;
  
    // Filter by dietary preferences
    if (dietary_preferences.length > 0) {
      filteredProducts = this.filterByDietaryPreferences(filteredProducts, dietary_preferences);
    }
  
    const suggestions = filteredProducts
      .slice(0, max_results)
      .map((product, index) => `${index + 1}. ${this.formatProductSuggestion(product)}`)
      .join('\n\n');
  
    return {
      content: [
        {
          type: "text" as const,
          text: `Product suggestions in ${category}:\n\n${suggestions}`,
        },
      ],
    };
  }

• src/tools.ts:106-138 (schema)

  Tool schema definition including input schema with parameters: category (required), dietary_preferences, max_results, min_nutriscore.

  {
    name: "get_product_suggestions",
    description: "Get product suggestions based on dietary preferences or restrictions",
    inputSchema: {
      type: "object",
      properties: {
        category: {
          type: "string",
          description: "Product category to search within",
        },
        dietary_preferences: {
          type: "array",
          items: {
            type: "string",
            enum: ["vegan", "vegetarian", "gluten-free", "organic", "low-fat", "low-sugar", "high-protein"],
          },
          description: "Dietary preferences or restrictions",
        },
        max_results: {
          type: "number",
          description: "Maximum number of suggestions (default: 10)",
          minimum: 1,
          maximum: 50,
        },
        min_nutriscore: {
          type: "string",
          description: "Minimum Nutri-Score grade (a, b, c, d, e)",
          enum: ["a", "b", "c", "d", "e"],
        },
      },
      required: ["category"],
    },
  },

• src/index.ts:57-58 (registration)

  Registration in the MCP server request handler switch statement, dispatching to the handler function.

  case 'get_product_suggestions':
    return await handlers.handleGetProductSuggestions(args);

• src/handlers.ts:294-321 (helper)

  Helper method to filter products based on dietary preferences by checking labels, categories, and ingredients.

  private filterByDietaryPreferences(products: Product[], preferences: string[]): Product[] {
    return products.filter(product => {
      const labels = (product.labels || '').toLowerCase();
      const categories = (product.categories || '').toLowerCase();
      const ingredients = (product.ingredients_text || '').toLowerCase();
      
      return preferences.every(pref => {
        switch (pref) {
          case 'vegan':
            return labels.includes('vegan') || categories.includes('vegan');
          case 'vegetarian':
            return labels.includes('vegetarian') || categories.includes('vegetarian');
          case 'gluten-free':
            return labels.includes('gluten') && labels.includes('free');
          case 'organic':
            return labels.includes('organic') || labels.includes('bio');
          case 'low-fat':
            return labels.includes('low-fat') || labels.includes('light');
          case 'low-sugar':
            return labels.includes('sugar-free') || labels.includes('no-sugar');
          case 'high-protein':
            return labels.includes('high-protein') || labels.includes('protein');
          default:
            return true;
        }
      });
    });
  }

• src/handlers.ts:202-210 (helper)

  Helper method to format individual product suggestions including summary and scores.

  private formatProductSuggestion(product: Product): string {
    const summary = this.formatProductSummary(product);
    const scores = [];
    if (product.nutriscore_grade) scores.push(`Nutri-Score: ${product.nutriscore_grade.toUpperCase()}`);
    if (product.nova_group) scores.push(`Processing: NOVA ${product.nova_group}`);
    if (product.ecoscore_grade) scores.push(`Eco: ${product.ecoscore_grade.toUpperCase()}`);
    
    return summary + (scores.length > 0 ? `\nScores: ${scores.join(' | ')}` : '');
  }