Switch from IsLastStep to RemainingSteps for research_assistant (#103)

src/agents/research_assistant.py

@@ -7,7 +7,7 @@
 from langchain_core.runnables import RunnableConfig, RunnableLambda, RunnableSerializable
 from langgraph.checkpoint.memory import MemorySaver
 from langgraph.graph import END, MessagesState, StateGraph
-from langgraph.managed import IsLastStep
+from langgraph.managed import RemainingSteps
 from langgraph.prebuilt import ToolNode
 
 from agents.llama_guard import LlamaGuard, LlamaGuardOutput, SafetyAssessment
@@ -22,7 +22,7 @@ class AgentState(MessagesState, total=False):
     """
 
     safety: LlamaGuardOutput
-    is_last_step: IsLastStep
+    remaining_steps: RemainingSteps
 
 
 web_search = DuckDuckGoSearchResults(name="WebSearch")
@@ -75,7 +75,7 @@ async def acall_model(state: AgentState, config: RunnableConfig) -> AgentState:
     if safety_output.safety_assessment == SafetyAssessment.UNSAFE:
         return {"messages": [format_safety_message(safety_output)], "safety": safety_output}
 
-    if state["is_last_step"] and response.tool_calls:
+    if state["remaining_steps"] < 2 and response.tool_calls:
         return {
             "messages": [
                 AIMessage(