Add exponential backoff retry for Gemini 503s

src/agent.py

@@ -97,6 +97,12 @@ def send_email(to_email: str, subject: str, body: str) -> str:
 
 tools = [send_whatsapp, set_reminder, schedule_calendar, trigger_utility_scraper, get_k8s_pods, delete_k8s_pod, send_email]
 
+from tenacity import retry, stop_after_attempt, wait_exponential
+
+@retry(stop=stop_after_attempt(5), wait=wait_exponential(multiplier=1, min=4, max=20))
+def _invoke_with_retry(agent, messages):
+    return agent.invoke({"messages": messages})
+
 @activity.defn
 def run_agent_activity(payload: dict) -> str:
     user_request = payload.get("text", "")
@@ -122,5 +128,5 @@ TOOLS AVAILABLE:
 """
     
     agent = create_react_agent(llm, tools)
-    result = agent.invoke({"messages": [("system", system_prompt), ("user", user_request)]})
+    result = _invoke_with_retry(agent, [("system", system_prompt), ("user", user_request)])
     return result["messages"][-1].content