diff --git a/examples/rag_pipeline.py b/examples/rag_pipeline.py
index bdb22cb4a..045d2162a 100644
--- a/examples/rag_pipeline.py
+++ b/examples/rag_pipeline.py
@@ -1,4 +1,5 @@
 """RAG pipeline"""
+
 import asyncio
 
 from pydantic import BaseModel
diff --git a/examples/rag_search.py b/examples/rag_search.py
index b7f75385e..258c5ba60 100644
--- a/examples/rag_search.py
+++ b/examples/rag_search.py
@@ -1,4 +1,5 @@
-"""Agent with RAG search"""
+"""Agent with RAG search."""
+
 import asyncio
 
 from examples.rag_pipeline import DOC_PATH, QUESTION
@@ -8,7 +9,8 @@ from metagpt.roles import Sales
 
 
 async def search():
-    """Agent with RAG search"""
+    """Agent with RAG search."""
+
     store = SimpleEngine.from_docs(input_files=[DOC_PATH])
     role = Sales(profile="Sales", store=store)
     result = await role.run(QUESTION)
diff --git a/metagpt/rag/engines/__init__.py b/metagpt/rag/engines/__init__.py
index 4e862b908..373181384 100644
--- a/metagpt/rag/engines/__init__.py
+++ b/metagpt/rag/engines/__init__.py
@@ -1,6 +1,5 @@
 """Engines init"""
 
-__all__ = ["SimpleEngine"]
-
-
 from metagpt.rag.engines.simple import SimpleEngine
+
+__all__ = ["SimpleEngine"]
diff --git a/metagpt/rag/engines/simple.py b/metagpt/rag/engines/simple.py
index 9afee9b35..dc13adf28 100644
--- a/metagpt/rag/engines/simple.py
+++ b/metagpt/rag/engines/simple.py
@@ -1,6 +1,5 @@
 """Simple Engine."""
 
-
 from typing import Optional
 
 from llama_index.core import SimpleDirectoryReader, VectorStoreIndex
diff --git a/metagpt/rag/factories/__init__.py b/metagpt/rag/factories/__init__.py
index d7fcc27ed..56101de7c 100644
--- a/metagpt/rag/factories/__init__.py
+++ b/metagpt/rag/factories/__init__.py
@@ -1,4 +1,5 @@
 """RAG factories"""
+
 from metagpt.rag.factories.retriever import get_retriever
 from metagpt.rag.factories.ranker import get_rankers
 from metagpt.rag.factories.embedding import get_rag_embedding
diff --git a/metagpt/rag/factories/base.py b/metagpt/rag/factories/base.py
index 5d27eb273..5c6173a3f 100644
--- a/metagpt/rag/factories/base.py
+++ b/metagpt/rag/factories/base.py
@@ -1,4 +1,5 @@
 """Base Factory."""
+
 from typing import Any, Callable
 
 
diff --git a/metagpt/rag/factories/embedding.py b/metagpt/rag/factories/embedding.py
index ebabf7b8a..4247db256 100644
--- a/metagpt/rag/factories/embedding.py
+++ b/metagpt/rag/factories/embedding.py
@@ -1,4 +1,5 @@
 """RAG Embedding Factory."""
+
 from llama_index.core.embeddings import BaseEmbedding
 from llama_index.embeddings.azure_openai import AzureOpenAIEmbedding
 from llama_index.embeddings.openai import OpenAIEmbedding
diff --git a/metagpt/rag/factories/index.py b/metagpt/rag/factories/index.py
index eaa2ab97c..3e0c13c25 100644
--- a/metagpt/rag/factories/index.py
+++ b/metagpt/rag/factories/index.py
@@ -1,4 +1,5 @@
 """RAG Index Factory."""
+
 import chromadb
 from llama_index.core import StorageContext, VectorStoreIndex, load_index_from_storage
 from llama_index.core.embeddings import BaseEmbedding
diff --git a/metagpt/rag/interface.py b/metagpt/rag/interface.py
index 8039e76d5..9f5d8375c 100644
--- a/metagpt/rag/interface.py
+++ b/metagpt/rag/interface.py
@@ -1,4 +1,5 @@
 """RAG Interfaces."""
+
 from typing import Any, Protocol
 
 
diff --git a/metagpt/rag/llm.py b/metagpt/rag/llm.py
index fdcd1904f..9c946698a 100644
--- a/metagpt/rag/llm.py
+++ b/metagpt/rag/llm.py
@@ -1,4 +1,5 @@
 """RAG LLM."""
+
 from typing import Any
 
 from llama_index.core.llms import (
diff --git a/metagpt/rag/retrievers/__init__.py b/metagpt/rag/retrievers/__init__.py
index 7f4371423..2f70e0328 100644
--- a/metagpt/rag/retrievers/__init__.py
+++ b/metagpt/rag/retrievers/__init__.py
@@ -1,4 +1,4 @@
-"""Retrievers init"""
+"""Retrievers init."""
 
 from metagpt.rag.retrievers.hybrid_retriever import SimpleHybridRetriever
 
diff --git a/metagpt/rag/retrievers/base.py b/metagpt/rag/retrievers/base.py
index 87d678809..ea73a0017 100644
--- a/metagpt/rag/retrievers/base.py
+++ b/metagpt/rag/retrievers/base.py
@@ -1,6 +1,5 @@
 """Base retriever."""
 
-
 from abc import abstractmethod
 
 from llama_index.core.retrievers import BaseRetriever
diff --git a/metagpt/rag/retrievers/bm25_retriever.py b/metagpt/rag/retrievers/bm25_retriever.py
index c451e98fd..2965f685a 100644
--- a/metagpt/rag/retrievers/bm25_retriever.py
+++ b/metagpt/rag/retrievers/bm25_retriever.py
@@ -1,4 +1,5 @@
 """BM25 retriever."""
+
 from llama_index.core.schema import BaseNode
 from llama_index.retrievers.bm25 import BM25Retriever
 from rank_bm25 import BM25Okapi
diff --git a/metagpt/rag/retrievers/chroma_retriever.py b/metagpt/rag/retrievers/chroma_retriever.py
index 035969421..7832fa878 100644
--- a/metagpt/rag/retrievers/chroma_retriever.py
+++ b/metagpt/rag/retrievers/chroma_retriever.py
@@ -1,10 +1,11 @@
 """Chroma retriever."""
+
 from llama_index.core.retrievers import VectorIndexRetriever
 from llama_index.core.schema import BaseNode
 
 
 class ChromaRetriever(VectorIndexRetriever):
-    """FAISS retriever."""
+    """Chroma retriever."""
 
     def add_nodes(self, nodes: list[BaseNode], **kwargs):
         """Support add nodes"""
diff --git a/metagpt/rag/retrievers/faiss_retriever.py b/metagpt/rag/retrievers/faiss_retriever.py
index 8c1bc8f8a..8c649b53e 100644
--- a/metagpt/rag/retrievers/faiss_retriever.py
+++ b/metagpt/rag/retrievers/faiss_retriever.py
@@ -1,4 +1,5 @@
 """FAISS retriever."""
+
 from llama_index.core.retrievers import VectorIndexRetriever
 from llama_index.core.schema import BaseNode
 
diff --git a/metagpt/rag/retrievers/hybrid_retriever.py b/metagpt/rag/retrievers/hybrid_retriever.py
index 1a752855a..14deb6ebf 100644
--- a/metagpt/rag/retrievers/hybrid_retriever.py
+++ b/metagpt/rag/retrievers/hybrid_retriever.py
@@ -1,4 +1,5 @@
 """Hybrid retriever."""
+
 import copy
 
 from llama_index.core.schema import BaseNode, QueryType