refactor: refine the graph structure

src/graph/builder.py

@@ -3,6 +3,7 @@
 
 from langgraph.graph import StateGraph, START, END
 from langgraph.checkpoint.memory import MemorySaver
+from src.prompts.planner_model import StepType
 
 from .types import State
 from .nodes import (
@@ -17,6 +18,22 @@ from .nodes import (
 )
 
 
+def continue_to_running_research_step(state: State):
+    current_plan = state.get("current_plan")
+    if not current_plan or not current_plan.steps:
+        return "planner"
+    if all(step.execution_res for step in current_plan.steps):
+        return "planner"
+    for step in current_plan.steps:
+        if not step.execution_res:
+            break
+    if step.step_type and step.step_type == StepType.RESEARCH:
+        return "researcher"
+    if step.step_type and step.step_type == StepType.PROCESSING:
+        return "coder"
+    return "planner"
+
+
 def _build_base_graph():
     """Build and return the base state graph with all nodes and edges."""
     builder = StateGraph(State)
@@ -29,6 +46,12 @@ def _build_base_graph():
     builder.add_node("researcher", researcher_node)
     builder.add_node("coder", coder_node)
     builder.add_node("human_feedback", human_feedback_node)
+    builder.add_edge("background_investigator", "planner")
+    builder.add_conditional_edges(
+        "research_team",
+        continue_to_running_research_step,
+        ["planner", "researcher", "coder"],
+    )
     builder.add_edge("reporter", END)
     return builder
 

src/graph/nodes.py

@@ -24,7 +24,7 @@ from src.tools import (
 from src.config.agents import AGENT_LLM_MAP
 from src.config.configuration import Configuration
 from src.llms.llm import get_llm_by_type
-from src.prompts.planner_model import Plan, StepType
+from src.prompts.planner_model import Plan
 from src.prompts.template import apply_prompt_template
 from src.utils.json_utils import repair_json_output
 
@@ -45,22 +45,24 @@ def handoff_to_planner(
     return
 
 
-def background_investigation_node(
-    state: State, config: RunnableConfig
-) -> Command[Literal["planner"]]:
+def background_investigation_node(state: State, config: RunnableConfig):
     logger.info("background investigation node is running.")
     configurable = Configuration.from_runnable_config(config)
     query = state["messages"][-1].content
+    background_investigation_results = None
     if SELECTED_SEARCH_ENGINE == SearchEngine.TAVILY.value:
         searched_content = LoggedTavilySearch(
             max_results=configurable.max_search_results
         ).invoke(query)
-        background_investigation_results = None
         if isinstance(searched_content, list):
             background_investigation_results = [
-                {"title": elem["title"], "content": elem["content"]}
-                for elem in searched_content
+                f"## {elem['title']}\n\n{elem['content']}" for elem in searched_content
             ]
+            return {
+                "background_investigation_results": "\n\n".join(
+                    background_investigation_results
+                )
+            }
         else:
             logger.error(
                 f"Tavily search returned malformed response: {searched_content}"
@@ -69,14 +71,11 @@ def background_investigation_node(
         background_investigation_results = get_web_search_tool(
             configurable.max_search_results
         ).invoke(query)
-    return Command(
-        update={
+    return {
         "background_investigation_results": json.dumps(
             background_investigation_results, ensure_ascii=False
         )
-        },
-        goto="planner",
-    )
+    }
 
 
 def planner_node(
@@ -287,24 +286,10 @@ def reporter_node(state: State):
     return {"final_report": response_content}
 
 
-def research_team_node(
-    state: State,
-) -> Command[Literal["planner", "researcher", "coder"]]:
+def research_team_node(state: State):
     """Research team node that collaborates on tasks."""
     logger.info("Research team is collaborating on tasks.")
-    current_plan = state.get("current_plan")
-    if not current_plan or not current_plan.steps:
-        return Command(goto="planner")
-    if all(step.execution_res for step in current_plan.steps):
-        return Command(goto="planner")
-    for step in current_plan.steps:
-        if not step.execution_res:
-            break
-    if step.step_type and step.step_type == StepType.RESEARCH:
-        return Command(goto="researcher")
-    if step.step_type and step.step_type == StepType.PROCESSING:
-        return Command(goto="coder")
-    return Command(goto="planner")
+    pass
 
 
 async def _execute_agent_step(

tests/integration/test_nodes.py

@@ -82,27 +82,25 @@ def test_background_investigation_node_tavily(
         result = background_investigation_node(mock_state, mock_config)
 
         # Verify the result structure
-        assert isinstance(result, Command)
-        assert result.goto == "planner"
+        assert isinstance(result, dict)
 
         # Verify the update contains background_investigation_results
-        update = result.update
-        assert "background_investigation_results" in update
+        assert "background_investigation_results" in result
 
         # Parse and verify the JSON content
-        results = json.loads(update["background_investigation_results"])
-        assert isinstance(results, list)
+        results = result["background_investigation_results"]
 
         if search_engine == SearchEngine.TAVILY.value:
             mock_tavily_search.return_value.invoke.assert_called_once_with("test query")
-            assert len(results) == 2
-            assert results[0]["title"] == "Test Title 1"
-            assert results[0]["content"] == "Test Content 1"
+            assert (
+                results
+                == "## Test Title 1\n\nTest Content 1\n\n## Test Title 2\n\nTest Content 2"
+            )
         else:
             mock_web_search_tool.return_value.invoke.assert_called_once_with(
                 "test query"
             )
-            assert len(results) == 2
+            assert len(json.loads(results)) == 2
 
 
 def test_background_investigation_node_malformed_response(
@@ -116,13 +114,11 @@ def test_background_investigation_node_malformed_response(
         result = background_investigation_node(mock_state, mock_config)
 
         # Verify the result structure
-        assert isinstance(result, Command)
-        assert result.goto == "planner"
+        assert isinstance(result, dict)
 
         # Verify the update contains background_investigation_results
-        update = result.update
-        assert "background_investigation_results" in update
+        assert "background_investigation_results" in result
 
         # Parse and verify the JSON content
-        results = json.loads(update["background_investigation_results"])
-        assert results is None
+        results = result["background_investigation_results"]
+        assert json.loads(results) is None