Fix retriever

agent.py

@@ -56,6 +56,7 @@ def build_graph():
     def retriever(state: MessagesState):
         """Retriever node"""
         # Add system message if not present
+        messages = state["messages"]
         if not any(isinstance(m, SystemMessage) for m in messages):
             messages = [SystemMessage(content="You are a helpful AI assistant. Use the available tools to answer questions accurately. When providing your final answer, use the format: FINAL ANSWER: [your answer]")] + messages
         similar_question = vector_store.similarity_search(state["messages"][0].content)
@@ -64,7 +65,7 @@ def build_graph():
             content=f"Here I provide a similar question and answer for reference: \n\n{similar_question[0].page_content}",
         )
         
-        return {"messages": state["messages"] + [example_msg]}
+        return {"messages": messages + [example_msg]}
 
 
     builder = StateGraph(MessagesState)

pyproject.toml

@@ -7,6 +7,7 @@ requires-python = ">=3.12"
 dependencies = [
     "dotenv>=0.9.9",
     "gradio>=5.29.0",
+    "langchain>=0.3.25",
     "langchain-community>=0.3.23",
     "langchain-core>=0.3.59",
     "langchain-google-genai>=2.1.4",

uv.lock

@@ -362,6 +362,7 @@ source = { virtual = "." }
 dependencies = [
     { name = "dotenv" },
     { name = "gradio" },
+    { name = "langchain" },
     { name = "langchain-community" },
     { name = "langchain-core" },
     { name = "langchain-google-genai" },
@@ -378,6 +379,7 @@ dependencies = [
 requires-dist = [
     { name = "dotenv", specifier = ">=0.9.9" },
     { name = "gradio", specifier = ">=5.29.0" },
+    { name = "langchain", specifier = ">=0.3.25" },
     { name = "langchain-community", specifier = ">=0.3.23" },
     { name = "langchain-core", specifier = ">=0.3.59" },
     { name = "langchain-google-genai", specifier = ">=2.1.4" },