// 1. 註冊工具：名稱、參數格式與執行函式
await api.registerTool({
  name: names[action], description, inputSchema,
  annotations: { readOnlyHint, untrustedContentHint: true },
  execute: async (args, context = {}) => JSON.stringify(
    await run(action, args, 'WebMCP', context.signal)
  )
}, { signal: controller.signal });

// 2. run() 呼叫同站 REST API，帶入登入狀態與 nonce
const res = await fetch(cfg.api + action, {
  method: 'POST', credentials: 'same-origin',
  headers: { 'Content-Type': 'application/json',
             'X-WP-Nonce': cfg.nonce },
  body: JSON.stringify(args), signal
});
const data = await res.json();
// 成功後：products(data) / detail(data) / cart(data)

// 3. 每個 REST 工具都先驗證管理員身分與 nonce
'permission_callback' => function ($r) {
  return current_user_can('manage_options')
    && wp_verify_nonce(
      $r->get_header('X-WP-Nonce'), 'wp_rest'
    );
},

// 4. 通過商品與庫存檢查後，加入真實購物車
$key = WC()->cart->add_to_cart(
  $p->get_id(), 1, 0, [],
  ['merveille_demo_owner' => get_current_user_id()]
);
WC()->cart->calculate_totals();
WC()->cart->set_session();
return mwd_cart_data();