refactor(api): switch LLM provider from MiniMax to Google Generative AI

agent/agent.py

@@ -23,7 +23,14 @@ def supervisor_agent():
     return create_agent(
         model=get_llm(),
         # tools=[math_solver, websearch_agent, web_search_agents],
-        tools=[math_solver, web_search_agents, file_downloader, ocr_reader, list_files, http_get],
+        tools=[
+            math_solver,
+            web_search_agents,
+            file_downloader,
+            ocr_reader,
+            list_files,
+            http_get,
+        ],
         system_prompt=(
             f"You are a supervisor agent. "
             f"Current time is: {datetime.now(timezone.utc).isoformat()}. "
@@ -34,8 +41,8 @@ def supervisor_agent():
             f"to get a concise and accurate final answer. "
             f"If an image or photo file is attached, download and use the ocr_reader tool "
             f"to extract and describe the content before answering. "
-            f"Once you have found the answer, respond immediately. "
-            f"Do NOT continue searching or verifying unnecessarily — "
+            # f"Once you have found the answer, respond immediately. "
+            # f"Do NOT continue searching or verifying unnecessarily — "
             f"you have a limited number of action steps and must avoid exceeding them. "
             f"If you do not have enough information to answer the question "
             f"and no tool can help, respond with: "

agent/api/api.py

@@ -1,6 +1,6 @@
-# from langchain_google_genai import ChatGoogleGenerativeAI
+from langchain_google_genai import ChatGoogleGenerativeAI
 
-from langchain_community.chat_models import MiniMaxChat
+# from langchain_community.chat_models import MiniMaxChat
 
 _llm = None
 
@@ -9,6 +9,6 @@ def get_llm():
     """Return a shared LLM instance."""
     global _llm
     if _llm is None:
-        # _llm = ChatGoogleGenerativeAI(model="gemini-3-flash-preview")
-        _llm = MiniMaxChat(model="MiniMax-M2.5-highspeed")
+        _llm = ChatGoogleGenerativeAI(model="gemini-3.1-flash-lite-preview")
+        # _llm = MiniMaxChat(model="MiniMax-M2.7-highspeed")
     return _llm