openfoodfacts-mcp

Instructions

Implementation Reference

• src/tools/get-product.ts:131-177 (handler)

  The tool handler function for 'get_product' that fetches data from the Open Food Facts API and processes the response.

  async (args) => {
  	const fields = args.fields ?? DEFAULT_FIELDS;
  	const lang = args.language as string;
  
  	// For language-dependent fields, also request the lang-suffixed version
  	// so we can prefer the requested language regardless of the product's
  	// primary language.
  	const langFields: string[] = [];
  	for (const field of fields) {
  		if (LANGUAGE_DEPENDENT_FIELDS.includes(field)) {
  			langFields.push(`${field}_${lang}`);
  		}
  	}
  
  	const allFields = [...fields, ...langFields];
  	const params: Record<string, string> = {
  		fields: allFields.join(','),
  	};
  
  	const data = await offGet(config, `/api/v2/product/${args.barcode}.json`, params) as Record<string, unknown>;
  
  	// Prefer lang-suffixed values over unsuffixed (which map to the product's
  	// primary language and may not be what was requested).
  	const product = data.product as Record<string, unknown> | undefined;
  	if (product) {
  		for (const field of LANGUAGE_DEPENDENT_FIELDS) {
  			const langKey = `${field}_${lang}`;
  			if (product[langKey] !== undefined && product[langKey] !== null && product[langKey] !== '') {
  				product[field] = product[langKey];
  			}
  
  			// Remove the lang-suffixed field from output to keep response clean,
  			// unless the caller explicitly requested it.
  			if (!fields.includes(langKey)) {
  				// eslint-disable-next-line @typescript-eslint/no-dynamic-delete
  				delete product[langKey];
  			}
  		}
  	}
  
  	// Restructure the flat nutriments blob into a readable nested format
  	if (product?.nutriments) {
  		product.nutriments = restructureNutriments(product.nutriments as Record<string, unknown>);
  	}
  
  	return jsonResult(data);
  },

• src/tools/get-product.ts:108-118 (schema)

  The input schema validation and alias configuration for 'get_product'.

  const inputSchema = strictSchemaWithAliases(
  	{
  		barcode: z.string().describe('Product barcode (EAN-13, UPC-A, etc.)'),
  		fields: z.array(z.string()).optional().describe(`Fields to return. Defaults to: ${DEFAULT_FIELDS.join(', ')}`),
  		language: z.string().default('en').describe('Language code for language-dependent fields (product_name, generic_name, ingredients_text). Defaults to "en". When a product has a different primary language, the unsuffixed field names return that language\'s data — this param ensures you get the language you want.'),
  	},
  	{
  		code: 'barcode',
  		ean: 'barcode',
  	},
  );

• src/tools/get-product.ts:120-130 (registration)

  Registration of the 'get_product' tool with the MCP server.

  export function registerGetProduct(server: McpServer, config: Config): void {
  	server.registerTool(
  		'get_product',
  		{
  			title: 'Get product',
  			description: 'Get product information from Open Food Facts by barcode. Reads the primary database directly (no sync lag), so this is always current even when search_products returns stale results. Prefer this over search whenever you have a barcode. If this returns "product not found", the product genuinely isn\'t in the database — you can add it with add_or_edit_product.',
  			inputSchema,
  			annotations: {
  				readOnlyHint: true,
  			},
  		},