diff --git a/metagpt/provider/google_gemini_api.py b/metagpt/provider/google_gemini_api.py
index e4b3a3f17..5c1b92503 100644
--- a/metagpt/provider/google_gemini_api.py
+++ b/metagpt/provider/google_gemini_api.py
@@ -22,7 +22,6 @@ from metagpt.const import USE_CONFIG_TIMEOUT
 from metagpt.logs import log_llm_stream, logger
 from metagpt.provider.base_llm import BaseLLM
 from metagpt.provider.llm_provider_registry import register_provider
-from metagpt.schema import Message
 
 
 class GeminiGenerativeModel(GenerativeModel):
@@ -73,7 +72,7 @@ class GeminiLLM(BaseLLM):
     def _system_msg(self, msg: str) -> dict[str, str]:
         return {"role": "user", "parts": [msg]}
 
-    def format_msg(self, messages: Union[str, Message, list[dict], list[Message], list[str]]) -> list[dict]:
+    def format_msg(self, messages: Union[str, "Message", list[dict], list["Message"], list[str]]) -> list[dict]:
         """convert messages to list[dict]."""
         from metagpt.schema import Message
 
diff --git a/metagpt/tools/libs/index_repo.py b/metagpt/tools/libs/index_repo.py
index dc23987c9..720fec4fd 100644
--- a/metagpt/tools/libs/index_repo.py
+++ b/metagpt/tools/libs/index_repo.py
@@ -11,6 +11,7 @@ from pydantic import BaseModel, Field, model_validator
 
 from metagpt.config2 import Config
 from metagpt.logs import logger
+from metagpt.rag.engines import SimpleEngine
 from metagpt.rag.factories.embedding import RAGEmbeddingFactory
 from metagpt.rag.schema import FAISSIndexConfig, FAISSRetrieverConfig, LLMRankerConfig
 from metagpt.utils.common import aread, awrite, generate_fingerprint, list_files
@@ -99,8 +100,6 @@ class IndexRepo(BaseModel):
         await self._add_batch(filenames=filter_filenames, delete_filenames=delete_filenames)
 
     async def _add_batch(self, filenames: List[Union[str, Path]], delete_filenames: List[Union[str, Path]]):
-        from metagpt.rag.engines import SimpleEngine
-
         if not filenames:
             return
         engine = None
@@ -161,8 +160,6 @@ class IndexRepo(BaseModel):
         return pathnames, excludes
 
     async def _search(self, query: str, filters: Set[str]) -> List[NodeWithScore]:
-        from metagpt.rag.engines import SimpleEngine
-
         if not Path(self.filename).exists():
             return []
         engine = SimpleEngine.from_index(