getAllergenCheck

Instructions

Implementation Reference

• src/tools/helpers.ts:294-327 (handler)

  Core handler function that checks if a product contains a specific allergen by scanning allergens_tags, allergens_hierarchy, and traces_tags fields.

  export function checkAllergen(product: any, allergen: string): AllergenResult {
      const allergensTags = product.allergens_tags || [];
      const allergensHierarchy = product.allergens_hierarchy || [];
      const tracesTags = product.traces_tags || [];
  
      const allergenLower = allergen.toLowerCase();
  
      const allAllergenTags = [...new Set([...allergensTags, ...allergensHierarchy])];
      const allergenFound = allAllergenTags.some(tag =>
          tag.toLowerCase().includes(allergenLower)
      );
  
      const inTraces = tracesTags.some((tag: string) =>
          tag.toLowerCase().includes(allergenLower)
      );
  
      const allAllergens = allAllergenTags.map((tag: string) =>
          tag.replace('en:', '').replace(/-/g, ' ')
      );
  
      const traces = tracesTags.map((tag: string) =>
          tag.replace('en:', '').replace(/-/g, ' ')
      );
  
      return {
          barcode: product.barcode || product.code,
          productName: product.name || product.product_name || 'Unknown',
          allergenFound: allergenFound || inTraces,
          allergenChecked: allergen,
          allAllergens,
          allergensTags: allAllergenTags,
          traces
      };
  }

• src/tools/types.ts:55-63 (schema)

  Type definition for the allergen check result returned by checkAllergen.

  export interface AllergenResult {
      barcode: string;
      productName: string;
      allergenFound: boolean;
      allergenChecked: string;
      allAllergens: string[];
      allergensTags: string[];
      traces: string[];
  }

• src/tools/nutrition-tools.ts:77-105 (registration)

  Registration of the getAllergenCheck tool on the MCP server with its description, input schema, and handler callback that calls checkAllergen.

  server.registerTool('getAllergenCheck', {
      description: 'Check if a product contains a specific allergen (gluten, milk, eggs, nuts, peanuts, soy, fish, shellfish, etc.)',
      inputSchema: allergenCheckSchema
  }, async ({ nameOrBarcode, allergen }) => {
      try {
          const product = await findProduct(nameOrBarcode);
          if (!product) {
              return { content: [{ type: 'text' as const, text: `Product "${nameOrBarcode}" not found.` }], isError: true };
          }
          const result = checkAllergen(product, allergen);
  
          let message = result.allergenFound
              ? `WARNING: ${result.allergenChecked.toUpperCase()} found in this product!`
              : `${result.allergenChecked.toUpperCase()} not detected in this product.`;
  
          if (result.traces.length > 0) {
              message += `\n\nNote: May contain traces of: ${result.traces.join(', ')}`;
          }
  
          return {
              content: [{
                  type: 'text' as const,
                  text: `${message}\n\n${JSON.stringify(result, null, 2)}`
              }]
          };
      } catch (error: any) {
          return { content: [{ type: 'text' as const, text: `Error: ${error.message}` }], isError: true };
      }
  });

• src/tools/nutrition-tools.ts:18-21 (schema)

  Zod input schema for the getAllergenCheck tool specifying nameOrBarcode and allergen string parameters.

  const allergenCheckSchema = {
      nameOrBarcode: z.string().describe('Product name or barcode'),
      allergen: z.string().describe('Allergen to check for (e.g., "gluten", "milk", "eggs", "nuts", "peanuts", "soy", "fish", "shellfish")')
  };