feat: support duckduckgo search engine

src/config/tools.py

@@ -1,2 +1,15 @@
+import os
+import enum
+from dotenv import load_dotenv
+
+load_dotenv()
+
+
+class SearchEngine(enum.Enum):
+    TAVILY = "tavily"
+    DUCKDUCKGO = "duckduckgo"
+
+
 # Tool configuration
-TAVILY_MAX_RESULTS = 3
+SELECTED_SEARCH_ENGINE = os.getenv("SEARCH_API", SearchEngine.TAVILY.value)
+SEARCH_MAX_RESULTS = 3