openfoodfacts-mcp

Instructions

Implementation Reference

• src/tools/call-api.ts:50-55 (handler)

  The handler logic for the 'call_api' tool, which uses 'offRequest' to execute the API call and returns a JSON result.

  	async (args) => {
  		const data = await offRequest(config, args.method, args.endpoint, args.params, args.json_body);
  
  		return jsonResult(data as Record<string, unknown>);
  	},
  );

• src/tools/call-api.ts:8-26 (schema)

  The Zod input schema defining the parameters for the 'call_api' tool.

  const inputSchema = strictSchemaWithAliases(
  	{
  		method: z.enum([
  			'GET',
  			'POST',
  			'PUT',
  			'PATCH',
  			'DELETE',
  		]).default('GET').describe('HTTP method (default: GET)'),
  		endpoint: z.string().describe('API endpoint path (e.g. "/api/v2/product/3017620422003.json")'),
  		params: z.record(z.string()).optional().describe('Query parameters (for GET) or form-encoded body fields (for POST/PUT/PATCH to v1/v2 endpoints like /cgi/product_jqm2.pl). Auth fields are added automatically.'),
  		json_body: z.record(z.unknown()).optional().describe('Raw JSON body for v3 endpoints (e.g. PATCH /api/v3/product/{code}). When set, params is ignored and Content-Type is application/json. Auth fields are injected at the top level. Use this for structured writes like packagings.'),
  	},
  	{
  		path: 'endpoint',
  		url: 'endpoint',
  		body: 'json_body',
  	},
  );

• src/tools/call-api.ts:28-56 (registration)

  The function that registers the 'call_api' tool with the MCP server.

  export function registerCallApi(server: McpServer, config: Config): void {
  	server.registerTool(
  		'call_api',
  		{
  			title: 'Call API',
  			description: `Make a direct call to any Open Food Facts API endpoint. Use get_api_docs to see available endpoints. Auth credentials are included automatically for write operations if configured.
  
  Two body modes for writes:
  - params: form-encoded (for /cgi/*.pl and /api/v2/* legacy endpoints)
  - json_body: raw JSON (for /api/v3/* endpoints — required for structured fields like packagings)
  
  Example v3 packagings write:
    method: PATCH
    endpoint: /api/v3/product/0123456789012
    json_body: {"fields":"packagings","product":{"packagings":[{"number_of_units":1,"shape":{"id":"en:bag"},"material":{"id":"en:plastic"},"recycling":{"id":"en:recycle"}}]}}
  
  WARNING: Do NOT use old-style prepared nutrition params like nutriment_fat_prepared — they have a known server bug that stores data incorrectly. Use new-style params instead: nutrition_input_sets_prepared_100g_nutrients_fat_value_string=0.5`,
  			inputSchema,
  			annotations: {
  				readOnlyHint: false,
  			},
  		},
  		async (args) => {
  			const data = await offRequest(config, args.method, args.endpoint, args.params, args.json_body);
  
  			return jsonResult(data as Record<string, unknown>);
  		},
  	);
  }