feat: solution for 'Повторный экзамен: Исследовательский бриф (план → шаги → сводка)'

.env.example

@@ -0,0 +1,5 @@
+# OpenAI API key
+OPENAI_API_KEY=your_openai_api_key_here
+
+# Tavily API key
+TAVILY_API_KEY=your_tavily_api_key_here

README.md

@@ -1,27 +1,90 @@
-# Экзамен: Самокорректирующийся агент
+# LangGraph Research Brief Agent
 
-Главная
-Мои задания
-Экзамен: Самокорректирующийся агент
-5Д
-EN
-Экзамен: Самокорректирующийся агент
-Зачёт
-Версия 2
-Дедлайн сдачи: 31.08.2026
+This project demonstrates how to build a LangGraph agent that generates a short research brief for a given topic.  
+The agent:
 
-В работе
+1. Creates an outline of 4‑5 research steps.  
+2. For each step, performs a web search (via Tavily) and writes a concise note.  
+3. Synthesizes all notes into a coherent brief.
 
-Требуется доработка
+## Prerequisites
 
-В вашем репозитории не реализовано требуемое LangGraph‑агент и отсутствует зависимость langgraph, необходимая для выполнения задачи. Пожалуйста, добавьте соответствующую реализацию и обновите требования.
+- Python 3.10+
+- A **Tavily** API key (free tier available).  
+- An **OpenAI** API key (or any compatible LLM provider).
 
-Редактирование ответа
+## Setup
 
-Заполните ответ и отправьте работу на проверку преподавателю.
+```bash
+# Clone the repository
+git clone https://github.com/your-username/langgraph-research-brief.git
+cd langgraph-research-brief
 
-Тип ответа
-Текст
-Ссылка
-Файлы
-Ссылка (
+# Create a virtual environment (optional but recommended)
+python -m venv venv
+source venv/bin/activate   # On Windows: venv\Scripts\activate
+
+# Install dependencies
+pip install -r requirements.txt
+```
+
+Create a `.env` file in the project root based on the example:
+
+```bash
+cp .env.example .env
+```
+
+Edit `.env` and replace the placeholders with your actual keys:
+
+```
+OPENAI_API_KEY=sk-...
+TAVILY_API_KEY=your_tavily_key
+```
+
+## Running the Agent
+
+```bash
+python src/main.py
+```
+
+You should see output similar to:
+
+```
+=== Outline ===
+1. Identify the security requirements for MCP integration
+2. Review LangChain's authentication mechanisms
+3. Evaluate secure communication protocols
+4. Test the integration in a sandbox environment
+5. Document best practices and compliance checks
+
+=== Notes ===
+[Step 1] ... (5‑8 sentence note)
+[Step 2] ... (5‑8 sentence note)
+...
+
+=== Final Brief ===
+...
+```
+
+## Project Structure
+
+```
+src/
+├── main.py          # Entry point
+├── graph.py         # LangGraph definition
+├── nodes.py         # Node implementations
+├── state.py         # TypedDict for state
+├── .env.example     # Environment variable template
+requirements.txt
+README.md
+```
+
+## Customization
+
+- **Topic**: Change the `default_topic` variable in `src/main.py` to generate a brief on a different subject.  
+- **LLM**: Swap `ChatOpenAI` for another provider (e.g., Ollama) by adjusting the imports and initialization in `src/nodes.py`.  
+- **Search**: Replace `TavilySearchResults` with another search tool if desired.
+
+## License
+
+MIT License

requirements.txt

@@ -1,3 +1,5 @@
 langgraph
 langchain-openai
-openai
+langchain-tavily
+tavily-python
+python-dotenv

src/graph.py

@@ -1,92 +1,28 @@
-import json
-from typing import Dict, Any
-from langgraph.graph import StateGraph, END
-from langchain_openai import ChatOpenAI
-from .state import PlanningState
+from langgraph import StateGraph
+from src.state import BriefState
+from src.nodes import outline_node, research_step_node, synthesize_node
 
-def planning(state: PlanningState) -> PlanningState:
-    """LLM node that splits the task into 3‑6 concrete steps."""
-    llm = ChatOpenAI(temperature=0)
-    prompt = (
-        f"Task: {state['task']}\n\n"
-        "Please break this task into 3-6 concrete steps. "
-        "Return the steps as a numbered list or a JSON array. "
-        "Do not add any extra text."
-    )
-    response = llm.invoke(prompt)
-    text = response.content.strip()
+def build_graph() -> StateGraph:
+    graph = StateGraph(BriefState)
 
-    # Try to parse JSON first
-    plan: List[str] | None = None
-    try:
-        parsed = json.loads(text)
-        if isinstance(parsed, list):
-            plan = [str(item) for item in parsed]
-    except Exception:
-        pass
+    # Add nodes
+    graph.add_node("outline", outline_node)
+    graph.add_node("research_step", research_step_node)
+    graph.add_node("synthesize", synthesize_node)
 
-    # Fallback: parse numbered list
-    if plan is None:
-        plan = []
-        for line in text.splitlines():
-            line = line.strip()
-            if not line:
-                continue
-            # Remove leading number if present
-            if '.' in line:
-                _, rest = line.split('.', 1)
-                step = rest.strip()
+    # Define the condition for looping research steps
+    def condition(state: BriefState):
+        if state["step_index"] < len(state["outline"]):
+            return "research_step"
         else:
-                step = line
-            plan.append(step)
+            return "synthesize"
 
-    state["plan"] = plan
-    state["current_step"] = 0
-    state["results"] = []
-    return state
+    # Build edges
+    graph.add_edge("outline", "research_step")
+    graph.add_conditional_edges("research_step", condition, {
+        "research_step": "research_step",
+        "synthesize": "synthesize"
+    })
+    graph.add_edge("synthesize", "__end__")
 
-def execution(state: PlanningState) -> PlanningState:
-    """Execute one step of the plan."""
-    llm = ChatOpenAI(temperature=0)
-    step = state["plan"][state["current_step"]]
-    prompt = (
-        f"Task: {state['task']}\n\n"
-        f"You are executing step {state['current_step'] + 1} of the plan.\n\n"
-        f"Step: {step}\n\n"
-        "Provide the result of this step."
-    )
-    response = llm.invoke(prompt)
-    result = response.content.strip()
-    state["results"].append(result)
-    state["current_step"] += 1
-    return state
-
-def should_continue(state: PlanningState) -> str:
-    """Decide whether to loop back to execution or finish."""
-    if state["current_step"] < len(state["plan"]):
-        return "execute"
-    return "finish"
-
-def create_graph() -> StateGraph:
-    graph = StateGraph(PlanningState)
-
-    graph.add_node("planning", planning)
-    graph.add_node("execution", execution)
-    graph.add_node("finish", lambda state: state)
-
-    graph.add_conditional_edges(
-        "planning",
-        lambda _: "execute",
-        {"execute": "execution"}
-    )
-
-    graph.add_conditional_edges(
-        "execution",
-        should_continue,
-        {"execute": "execution", "finish": "finish"}
-    )
-
-    graph.set_entry_point("planning")
-    graph.set_finish_point("finish")
-
-    return graph
+    return graph.compile()

src/main.py

@@ -1,34 +1,38 @@
 import os
-from src.graph import create_graph
-from src.state import PlanningState
+from dotenv import load_dotenv
+from src.graph import build_graph
+from src.state import BriefState
 
-def main() -> None:
-    # Ensure the OpenAI API key is set
-    if "OPENAI_API_KEY" not in os.environ:
-        raise RuntimeError("Please set the OPENAI_API_KEY environment variable.")
+def main():
+    # Load environment variables
+    load_dotenv()
+    # Default topic
+    default_topic = "Как студенту безопасно подключать MCP к LangChain"
 
-    task = "Compare Python and JavaScript"
-    initial_state: PlanningState = {
-        "task": task,
-        "plan": None,
-        "current_step": 0,
-        "results": []
+    # Initial state
+    initial_state: BriefState = {
+        "topic": default_topic,
+        "outline": None,
+        "step_index": 0,
+        "notes": [],
+        "final_brief": None
     }
 
-    graph = create_graph()
+    # Build and run the graph
+    graph = build_graph()
     final_state = graph.invoke(initial_state)
 
-    print("\n=== Plan ===")
-    for i, step in enumerate(final_state["plan"], 1):
+    # Print results
+    print("\n=== Outline ===")
+    for i, step in enumerate(final_state["outline"], 1):
         print(f"{i}. {step}")
 
-    print("\n=== Results ===")
-    for i, res in enumerate(final_state["results"], 1):
-        print(f"[Step {i}] {res}")
+    print("\n=== Notes ===")
+    for i, note in enumerate(final_state["notes"], 1):
+        print(f"[Step {i}] {note}\n")
 
-    print("\n=== Final Summary ===")
-    summary = "\n".join(final_state["results"])
-    print(summary)
+    print("\n=== Final Brief ===")
+    print(final_state["final_brief"])
 
 if __name__ == "__main__":
     main()

src/nodes.py

@@ -0,0 +1,83 @@
+import os
+import re
+from typing import Dict, Any
+from langchain_openai import ChatOpenAI
+from langchain_tavily import TavilySearchResults
+from src.state import BriefState
+
+# Load API keys from environment
+OPENAI_API_KEY = os.getenv("OPENAI_API_KEY")
+TAVILY_API_KEY = os.getenv("TAVILY_API_KEY")
+
+# Initialize LLM and Tavily
+llm = ChatOpenAI(model="gpt-3.5-turbo", temperature=0.2, openai_api_key=OPENAI_API_KEY)
+tavily = TavilySearchResults(tavily_api_key=TAVILY_API_KEY, max_results=3)
+
+def outline_node(state: BriefState) -> Dict[str, Any]:
+    """
+    Generate a concise outline of 4-5 research steps for the given topic.
+    """
+    topic = state["topic"]
+    prompt = (
+        f"Create a concise outline of 4-5 research steps for the topic: \"{topic}\".\n"
+        "Return the steps as a numbered list, one step per line."
+    )
+    response = llm.invoke(prompt)
+    text = response.content if hasattr(response, "content") else str(response)
+
+    # Extract lines that look like numbered steps
+    steps = re.findall(r"^\s*\d+\.\s*(.+)$", text, re.MULTILINE)
+    if not steps:
+        # Fallback: split by newlines
+        steps = [line.strip() for line in text.splitlines() if line.strip()]
+    state["outline"] = steps
+    state["step_index"] = 0
+    state["notes"] = []
+    return {"outline": steps, "step_index": 0, "notes": []}
+
+def research_step_node(state: BriefState) -> Dict[str, Any]:
+    """
+    Perform a web search for the current outline step and generate a short note.
+    """
+    outline = state["outline"]
+    idx = state["step_index"]
+    if idx >= len(outline):
+        return {}
+
+    current_step = outline[idx]
+    # Perform web search
+    search_results = tavily.invoke({"query": current_step})
+    # Prepare a prompt for summarization
+    prompt = (
+        f"Using the following web search results, write a concise note (5-8 sentences) about the topic:\n\n"
+        f"{search_results}\n\n"
+        f"Note:\n"
+    )
+    response = llm.invoke(prompt)
+    note = response.content if hasattr(response, "content") else str(response)
+
+    # Append note and increment step_index
+    notes = state["notes"] + [note.strip()]
+    state["notes"] = notes
+    state["step_index"] = idx + 1
+    return {"notes": notes, "step_index": idx + 1}
+
+def synthesize_node(state: BriefState) -> Dict[str, Any]:
+    """
+    Combine all notes into a coherent brief with headings.
+    """
+    outline = state["outline"]
+    notes = state["notes"]
+    combined = ""
+    for step, note in zip(outline, notes):
+        combined += f"**{step}**\n\n{note}\n\n"
+
+    prompt = (
+        f"Using the following sections, write a concise research brief (1 page) that summarizes the key points.\n\n"
+        f"{combined}\n\n"
+        f"Brief:\n"
+    )
+    response = llm.invoke(prompt)
+    final_brief = response.content if hasattr(response, "content") else str(response)
+    state["final_brief"] = final_brief.strip()
+    return {"final_brief": state["final_brief"]}

src/state.py

@@ -1,7 +1,8 @@
 from typing import TypedDict, List, Optional
 
-class PlanningState(TypedDict):
-    task: str
-    plan: Optional[List[str]]
-    current_step: int
-    results: List[str]
+class BriefState(TypedDict):
+    topic: str
+    outline: List[str] | None
+    step_index: int
+    notes: List[str]
+    final_brief: str | None