diff --git a/agent.py b/agent.py
new file mode 100644
index 0000000..8628897
--- /dev/null
+++ b/agent.py
@@ -0,0 +1,39 @@
+"""
+Agent definition using LangChain create_agent.
+"""
+
+import os
+from langchain_openai import ChatOpenAI
+from langchain.agents import create_agent
+from langchain_core.messages import HumanMessage
+from tools import search_knowledge_base, add_to_knowledge_base
+
+# LLM – Ollama via BroJS endpoint (placeholder)
+llm = ChatOpenAI(
+    model="openai/gpt-oss-20b:free",
+    base_url="https://platform.brojs.ru/jrnl-bh/api/inference/v1",
+    api_key=os.getenv("JOURNAL_MCP_PAT"),
+    temperature=0.5,
+)
+
+agent = create_agent(
+    llm=llm,
+    tools=[search_knowledge_base, add_to_knowledge_base],
+    system_prompt="You are a helpful assistant with access to a knowledge base.",
+)
+
+async def main():
+    # Simple demo: add and search
+    await agent.ainvoke(
+        {"messages": [HumanMessage(content="Add sample text about Python")]},
+        {"configurable": {"thread_id": "demo-1"}},
+    )
+    result = await agent.ainvoke(
+        {"messages": [HumanMessage(content="Search for Python")]},
+        {"configurable": {"thread_id": "demo-1"}},
+    )
+    print(result["messages"][-1].content)
+
+if __name__ == "__main__":  # pragma: no cover
+    import asyncio
+    asyncio.run(main())