125 lines
4.0 KiB
Python
125 lines
4.0 KiB
Python
import os
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import asyncio
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from typing import TypedDict, Annotated
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from langchain_openai import ChatOpenAI
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from langchain_core.messages import HumanMessage
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from langchain.tools import tool
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from deepagents import create_deep_agent
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from deepagents.backends import FilesystemBackend, LocalShellBackend, CompositeBackend
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from langgraph.graph import StateGraph, START, END
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from langgraph.graph.message import add_messages
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# ---------- LLM ----------
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llm = ChatOpenAI(
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model="openai/gpt-oss-20b:free",
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base_url="https://openrouter.ai/api/v1",
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api_key=os.getenv("OPENAI_API_KEY"),
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temperature=0.0,
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)
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# ---------- Backend for deepagents ----------
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backend = CompositeBackend([
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LocalShellBackend(workspace_dir="./workspace"),
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FilesystemBackend(),
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])
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# ---------- State definition ----------
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class ReflectState(TypedDict):
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question: str
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draft: str
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critique: str
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verdict: str # ok | needs_revision
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round: int
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max_rounds: int
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# ---------- LangGraph nodes ----------
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async def draft_answer(state: ReflectState) -> ReflectState:
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prompt = f"Write a concise answer (5–10 sentences) to the following question:\n\n{state['question']}"
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response = await llm.ainvoke([HumanMessage(content=prompt)])
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state["draft"] = response.content.strip()
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return state
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async def reflect(state: ReflectState) -> ReflectState:
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prompt = (
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"You are a critic. Evaluate the draft answer for completeness, specificity, and lack of filler.\n"
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"Return a verdict ('ok' or 'needs_revision') and 2–3 bullet points of critique.\n"
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f"Draft: {state['draft']}"
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)
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response = await llm.ainvoke([HumanMessage(content=prompt)])
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# Simple parsing: first line verdict, rest critique
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lines = response.content.strip().splitlines()
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verdict = lines[0].strip().lower()
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critique = "\n".join(lines[1:]).strip()
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state["verdict"] = verdict
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state["critique"] = critique
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return state
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async def rewrite(state: ReflectState) -> ReflectState:
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prompt = (
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"Rewrite the draft answer incorporating the following critique. Keep the answer concise (5–10 sentences).\n"
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f"Critique: {state['critique']}\n"
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f"Original draft: {state['draft']}"
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)
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response = await llm.ainvoke([HumanMessage(content=prompt)])
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state["draft"] = response.content.strip()
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state["round"] += 1
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return state
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# ---------- Graph construction ----------
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graph = StateGraph(ReflectState)
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graph.add_node("draft_answer", draft_answer)
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graph.add_node("reflect", reflect)
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graph.add_node("rewrite", rewrite)
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# Entry point
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graph.set_entry_point("draft_answer")
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# Transitions
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graph.add_edge("draft_answer", "reflect")
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# From reflect: if ok -> END, else if needs_revision and round < max_rounds -> rewrite
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graph.add_conditional_edges(
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"reflect",
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lambda state: (
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"END" if state["verdict"] == "ok" else (
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"rewrite" if state["round"] < state["max_rounds"] else "END"
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)
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),
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)
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graph.add_edge("rewrite", "reflect")
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app = graph.compile()
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# ---------- DeepAgent wrapper ----------
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@tool
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def run_graph(question: str, max_rounds: int = 2) -> str:
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"""Run the reflection graph for a given question."""
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initial_state: ReflectState = {
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"question": question,
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"draft": "",
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"critique": "",
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"verdict": "",
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"round": 0,
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"max_rounds": max_rounds,
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}
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result = app.invoke(initial_state)
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return result["draft"]
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agent = create_deep_agent(
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model=llm,
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tools=[run_graph],
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backend=backend,
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system_prompt="You are an assistant that can generate and improve answers using reflection. Use the provided tool to get a refined answer.",
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)
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async def main():
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question = "Объясни студенту разницу между tool и resource в MCP"
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response = await agent.ainvoke(
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{"messages": [HumanMessage(content=question)]},
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{"configurable": {"thread_id": "session-1"}},
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)
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print("Final answer:\n", response["messages"][-1].content)
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if __name__ == "__main__":
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asyncio.run(main())
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