diff --git a/.env.example b/.env.example
index f9a4a24..d65654b 100644
--- a/.env.example
+++ b/.env.example
@@ -155,3 +155,17 @@ RATE_LIMIT_MAX=100
 # ===========================================
 LOG_LEVEL=info
 LOG_FORMAT=json
+
+# ===========================================
+# Real-time Tools API Keys (可选)
+# ===========================================
+# Google Custom Search API
+# 注册地址: https://developers.google.com/custom-search/v1/overview
+# 免费额度: 100次/天，超出后 $5/1000次
+GOOGLE_SEARCH_API_KEY=
+GOOGLE_CSE_ID=
+
+# Exchange Rate API (可选，v4 API 免费无需配置)
+# 注册地址: https://www.exchangerate-api.com/
+# 免费版无需 Key，Premium 版需要
+EXCHANGE_RATE_API_KEY=