Add Gemini API key

agent.py

@@ -19,6 +19,7 @@ def build_graph():
         max_tokens=None,
         timeout=None,
         max_retries=2,
+        google_api_key=os.getenv("GOOGLE_API_KEY")  # Get API key from environment variable
         )
     tools = [add, subtract, multiply, divide, modulus, power, sqrt, web_search, search_wikipedia]