Update agent.py

agent.py

@@ -54,18 +54,21 @@ def llm_call(state: MessagesState):
 
 # Tool node
 def tool_node(state: MessagesState):
+    """Executes the tools"""
+    
     result = []
-    for tool_call in state["messages"][-1].tool_calls:
-        tool = tools_by_name[tool_call["name"]]
-        observation = tool.invoke(tool_call["args"])
-        result.append(ToolMessage(content=observation, tool_call_id=tool_call["id"]))
-    return {"messages": result}
+    for tool_call in state["messages"][-1].tool_calls:   # gives a list of the tools the LLM decided to call
+        tool = tools_by_name[tool_call["name"]]   # look up the actual tool function using a dictionary
+        observation = tool.invoke(tool_call["args"])   # executes the tool
+        result.append(ToolMessage(content=observation, tool_call_id=tool_call["id"]))   # the result from the tool is added to the memory
+    return {"messages": result}   # thanks to add_messages, LangGraph will automatically append the result to the agent's message history
 
 # Conditional edge function to route to the tool node or end based upon whether the LLM made a tool call
 def should_continue(state: MessagesState) -> Literal["Action", END]:
     """Decide if we should continue the loop or stop based upon whether the LLM made a tool call"""
 
-    last_message = state["messages"][-1]
+    last_message = state["messages"][-1]  # looks at the last message (usually from the LLM)
+    
     # If the LLM makes a tool call, then perform an action
     if last_message.tool_calls:
         return "Action"
@@ -82,9 +85,11 @@ builder.add_node("environment", tool_node)
 # Add edges to connect nodes
 builder.add_edge(START, "llm_call")
 builder.add_conditional_edges(
-    "llm_call", 
+    "llm_call",
     should_continue,
-    {"Action": "environment", END: END})  # Name returned by should_continue : Name of the next node
+    {"Action": "environment",  # name returned by should_continue : Name of the next node
+     END: END}
+)
 builder.add_edge("environment", "llm_call")
 
 gaia_agent = builder.compile()