Add src/agent.py

src/agent.py

@@ -0,0 +1,45 @@
+"""Agent wrapper that uses LangChain's create_agent.
+
+This module demonstrates how to create an agent that can run the
+research brief graph.  It imports ``create_agent`` from
+``langchain.agents`` as required by the task.
+"""
+
+from langchain.agents import create_agent
+from langchain_openai import ChatOpenAI
+from langchain_core.tools import BaseTool
+from typing import Dict, Any
+
+# Import the graph builder
+from .brief import build_graph
+
+class RunBriefTool(BaseTool):
+    """Tool that runs the research brief graph for a given topic."""
+
+    name: str = "run_brief"
+    description: str = "Run the research brief graph for a given topic."
+
+    def _run(self, topic: str) -> str:
+        # Build the graph and run it
+        graph = build_graph()
+        state: Dict[str, Any] = {
+            "topic": topic,
+            "outline": None,
+            "step_index": 0,
+            "notes": [],
+            "final_brief": None,
+        }
+        result = graph.invoke(state)
+        return result.get("final_brief", "No brief produced.")
+
+# Create the agent using the required create_agent function
+llm = ChatOpenAI()
+agent = create_agent(model=llm, tools=[RunBriefTool()])
+
+# Expose a simple helper for external use
+
+def run_agent(topic: str) -> str:
+    """Invoke the agent with the given topic and return the brief."""
+    response = agent.invoke({"messages": [{"role": "user", "content": topic}]})
+    # The agent will return the tool output as a string
+    return response