update private attributes in hybrid_retriever_tool file

tools/hybrid_retriever_tool.py

@@ -4,19 +4,24 @@ from sentence_transformers import SentenceTransformer
 from tavily import TavilyClient
 from openai import OpenAI
 from crewai_tools import RagTool
-from pydantic import Field
+from pydantic import Field, PrivateAttr
 import os
 
 class HybridRetrieverTool(RagTool):
     name: str = "Hybrid Retriever Tool"
     description: str = "Combines BM25 keyword scoring with semantic similarity for hybrid retrieval"
     alpha: float = Field(default=0.6, description="Weight between semantic and lexical scores")
+
+    # Define private attributes
+    _embedder: SentenceTransformer = PrivateAttr()
+    _tavily: TavilyClient = PrivateAttr()
+    _client: OpenAI = PrivateAttr()
     
     def __init__(self, **data):
         super().__init__(**data)
-        self.embedder = SentenceTransformer("all-MiniLM-L6-v2")
-        self.tavily = TavilyClient(api_key=os.getenv("TAVILY_API_KEY"))
-        self.client = OpenAI(api_key=os.getenv("OPENAI_API_KEY"))
+        self._embedder = SentenceTransformer("all-MiniLM-L6-v2")
+        self._tavily = TavilyClient(api_key=os.getenv("TAVILY_API_KEY"))
+        self._client = OpenAI(api_key=os.getenv("OPENAI_API_KEY"))
 
     def _build_corpus(self, topic):
         """Fetch up-to-date search results."""