Refactor HuggingFace model initialization to directly retrieve API token from environment variables

agent.py

@@ -61,8 +61,6 @@ def build_graph(provider: str = "google"):
         # Groq https://console.groq.com/docs/models
         llm = ChatGroq(model="qwen-qwq-32b", temperature=0) # optional : qwen-qwq-32b gemma2-9b-it
     elif provider == "huggingface":
-        # Get HuggingFace API token from environment variables
-        hf_token = os.environ.get("HF_TOKEN")
         llm = ChatHuggingFace(
             llm=HuggingFaceEndpoint(
                 repo_id="mistralai/Mistral-7B-Instruct-v0.2",
@@ -72,7 +70,7 @@ def build_graph(provider: str = "google"):
                 # "google/gemma-7b-it"
                 # "mosaicml/mpt-7b-instruct"
                 # "tiiuae/falcon-7b-instruct"
-                token=hf_token,
+                token=os.environ.get("HF_TOKEN"),
             ),
         )
     else: