add main.py

main.py

@@ -0,0 +1,81 @@
+"""Deep agent: web search + virtual files → real filesystem export."""
+import os
+import asyncio
+from pathlib import Path
+
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+from langchain_core.messages import HumanMessage
+from langchain.tools import tool
+from deepagents import create_deep_agent
+from deepagents.backends import LocalShellBackend, CompositeBackend
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    model="openai/gpt-oss-20b:free",
+    base_url="https://openrouter.ai/api/v1",
+    api_key=os.getenv("OPENAI_API_KEY"),
+    temperature=0.0,
+)
+
+WORKSPACE = Path("./workspace")
+REAL_OUT = Path("./output")
+
+
+@tool
+def web_search(query: str) -> str:
+    """Search the web for information and return snippets."""
+    try:
+        from duckduckgo_search import DDGS
+        with DDGS() as ddgs:
+            results = list(ddgs.text(query, max_results=5))
+        return "\n".join(f"{r['title']}: {r['body']}" for r in results)
+    except Exception as exc:
+        return f"Search error: {exc}"
+
+
+backend = CompositeBackend(
+    default=LocalShellBackend(
+        root_dir=str(WORKSPACE),
+        virtual_mode=True,
+        inherit_env=True,
+    ),
+)
+
+agent = create_deep_agent(
+    model=llm,
+    tools=[web_search],
+    backend=backend,
+    system_prompt=(
+        "You are a research agent. "
+        "Use web_search to find information, then create virtual files with write_file. "
+        "When done, export all virtual files to real filesystem by calling execute with "
+        "a shell command that copies /virtual/ contents to the output directory."
+    ),
+)
+
+
+async def main(query: str = "Python LangChain agent best practices 2024") -> None:
+    WORKSPACE.mkdir(parents=True, exist_ok=True)
+    REAL_OUT.mkdir(parents=True, exist_ok=True)
+
+    config = {"configurable": {"thread_id": "research-session-1"}}
+    result = await agent.ainvoke(
+        {"messages": [HumanMessage(
+            content=(
+                f"Search the web for: {query}\n"
+                "Save your findings to results.txt as a virtual file.\n"
+                "Then export the virtual file results.txt to the real filesystem "
+                f"at {REAL_OUT}/results.txt"
+            )
+        )]},
+        config,
+    )
+    print(result["messages"][-1].content)
+
+
+if __name__ == "__main__":
+    import sys
+    q = " ".join(sys.argv[1:]) if len(sys.argv) > 1 else "Python LangChain agent best practices 2024"
+    asyncio.run(main(q))