Add 122 Python example scripts + .env.example

Each of the 122 code slides now has a standalone .py script in
examples/slide-NNN/script.py with the LLM provider pattern from
bro-js/agents/teacher/assistant/src/angry_teacher/llm.py:
  - load_dotenv() + ChatOpenAI with base_url=https://llm.brojs.ru/v1
  - OPENAI_API_KEY from .env (with safe (or '' or None) pattern)
  - Same comment block with alternative model/base_url choices

Layout:
  - sec1/sec5: code extracted from slide-NN.js (addCodeBlock)
  - sec2/sec3/sec4: code extracted from sectionN.pptx via python-pptx
    (JetBrains Mono font shapes)

100 scripts contain runnable code, 22 are visual-only (dividers,
intro, recap) and just print the slide title.

Setup:
  cp .env.example .env       # fill OPENAI_API_KEY (or symlink to your
                              # teacher/assistant/.env)
  pip install -r requirements.txt
  python examples/slide-005/script.py

examples/slide-001/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 1: Untitled
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-01.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-001/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 1: Untitled')

examples/slide-002/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 2: Что такое LangChain в 2025+
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-02.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-002/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 2: Что такое LangChain в 2025+')

examples/slide-003/script.py

@@ -0,0 +1,49 @@
+"""
+Slide 3: pip install -- и сразу в дело
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-03.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-003/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 3 ===
+# 1. Core -- обязательно для всех остальных пакетов
+pip install langchain
+
+# 2. Provider-интеграции -- ставим только те, что нужны
+pip install langchain-openai
+pip install langchain-anthropic
+pip install langchain-google
+
+# 3. (опционально) дополнительные интеграции
+pip install langchain-community   # ~700 community-пакетов
+pip install langchain-classic     # legacy chains/AgentExecutor

examples/slide-004/script.py

@@ -0,0 +1,49 @@
+"""
+Slide 4: Первый вызов модели
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-04.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-004/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 4 ===
+# Один универсальный инициализатор для всех провайдеров
+from langchain.chat_models import init_chat_model
+
+# Формат: "<provider>:<model>"
+model = init_chat_model("openai:gpt-4.1-mini")
+
+# invoke -> BaseMessage; нам нужен .content
+result = model.invoke("Say hello in one sentence")
+print(result.content)
+
+# >>> "Hello! How can I help you today?"

examples/slide-005/script.py

@@ -0,0 +1,52 @@
+"""
+Slide 5: Переключение провайдера -- одна строка
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-05.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-005/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 5 ===
+from langchain.chat_models import init_chat_model
+
+# OpenAI
+m_openai = init_chat_model("openai:gpt-4.1-mini")
+
+# Anthropic
+m_anthropic = init_chat_model("anthropic:claude-3-7-sonnet-latest")
+
+# Google Vertex AI
+m_google = init_chat_model("google_vertexai:gemini-2.0-flash")
+
+# Все три -- объекты BaseChatModel. Один и тот же .invoke()
+for m in [m_openai, m_anthropic, m_google]:
+    print(type(m).__name__, ":", m.invoke("ping").content[:30])

examples/slide-006/script.py

@@ -0,0 +1,54 @@
+"""
+Slide 6: Стандартизированные сообщения
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-06.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-006/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 6 ===
+from langchain.messages import (
+    HumanMessage, AIMessage, SystemMessage, ToolMessage,
+)
+from langchain.chat_models import init_chat_model
+
+model = init_chat_model("openai:gpt-4.1-mini")
+
+messages = [
+    SystemMessage(content="You are a concise assistant."),
+    HumanMessage(content="What is LCEL?"),
+    AIMessage(content="LCEL = pipe-based composition in LangChain."),
+    HumanMessage(content="Show a one-line example."),
+]
+
+response = model.invoke(messages)
+print(response.content)

examples/slide-007/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 7: Потоковый вывод -- token за токеном
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-07.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-007/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 7 ===
+from langchain.chat_models import init_chat_model
+
+model = init_chat_model("openai:gpt-4.1-mini")
+
+# .stream() -> итератор по AIMessageChunk
+for chunk in model.stream("Write a haiku about Python"):
+    # У каждого chunk-а есть .content (текст) и .response_metadata
+    print(chunk.content, end="", flush=True)
+
+print()  # перевод строки после потока
+
+# Async-вариант: model.astream() -- то же самое в async-контексте
+import asyncio
+
+async def main():
+    async for chunk in model.astream("Write a haiku about async"):
+        print(chunk.content, end="", flush=True)

examples/slide-008/script.py

@@ -0,0 +1,53 @@
+"""
+Slide 8: ChatPromptTemplate -- декларативно
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-08.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-008/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 8 ===
+from langchain_core.prompts import ChatPromptTemplate
+from langchain.chat_models import init_chat_model
+
+prompt = ChatPromptTemplate.from_messages([
+    ("system", "Translate the following text to {language}."),
+    ("human", "{text}"),
+])
+
+model = init_chat_model("openai:gpt-4.1-mini")
+
+# .invoke() принимает dict и подставляет переменные
+messages = prompt.invoke({"language": "French", "text": "Hello world"})
+print(messages.to_messages())
+
+# -> [SystemMessage(...), HumanMessage(...)] -- готов к model.invoke()

examples/slide-009/script.py

@@ -0,0 +1,62 @@
+"""
+Slide 9: MessagesPlaceholder + few-shot
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-09.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-009/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 9 ===
+from langchain_core.prompts import (
+    ChatPromptTemplate, MessagesPlaceholder, FewShotChatMessagePromptTemplate,
+)
+
+# Few-shot блок: примеры "вопрос -> ответ"
+examples = [
+    {"input": "2+2", "output": "4"},
+    {"input": "3*3", "output": "9"},
+]
+example_prompt = ChatPromptTemplate.from_messages([
+    ("human", "{input}"),
+    ("ai", "{output}"),
+])
+few_shot = FewShotChatMessagePromptTemplate(
+    example_prompt=example_prompt, examples=examples,
+)
+
+# Сборка: system + few-shot + история + текущий вопрос
+prompt = ChatPromptTemplate.from_messages([
+    ("system", "You are a math assistant."),
+    few_shot,
+    MessagesPlaceholder("history"),
+    ("human", "{question}"),
+])

examples/slide-010/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 10: StrOutputParser -- самый частый
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-10.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-010/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 10 ===
+from langchain_core.prompts import ChatPromptTemplate
+from langchain_core.output_parsers import StrOutputParser
+from langchain.chat_models import init_chat_model
+
+prompt = ChatPromptTemplate.from_messages([
+    ("system", "Translate to French."),
+    ("human", "{text}"),
+])
+model = init_chat_model("openai:gpt-4.1-mini")
+
+# Склеиваем через LCEL: prompt | model | parser
+chain = prompt | model | StrOutputParser()
+
+# Теперь на выходе str, а не AIMessage
+result = chain.invoke({"text": "Hello world"})
+print(type(result).__name__, "->", result)
+# >>> str -> "Bonjour le monde"

examples/slide-011/script.py

@@ -0,0 +1,58 @@
+"""
+Slide 11: PydanticOutputParser -- типизированный выход
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-11.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-011/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 11 ===
+from pydantic import BaseModel, Field
+from langchain_core.prompts import ChatPromptTemplate
+from langchain_core.output_parsers import PydanticOutputParser
+from langchain.chat_models import init_chat_model
+
+class MovieReview(BaseModel):
+    title: str = Field(description="Movie title")
+    rating: int = Field(description="Rating from 1 to 10")
+    summary: str = Field(description="One-sentence summary")
+
+parser = PydanticOutputParser(pydantic_object=MovieReview)
+
+prompt = ChatPromptTemplate.from_messages([
+    ("system", "Extract review fields.\n{format_instructions}"),
+    ("human", "{review_text}"),
+]).partial(format_instructions=parser.get_format_instructions())
+
+chain = prompt | init_chat_model("openai:gpt-4.1-mini") | parser
+review = chain.invoke({"review_text": "Inception was brilliant. 9/10."})
+print(review.title, review.rating, review.summary)

examples/slide-012/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 12: with_structured_output -- рекомендованный путь
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-12.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-012/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 12 ===
+from pydantic import BaseModel, Field
+from langchain.chat_models import init_chat_model
+
+class Weather(BaseModel):
+    city: str = Field(description="City name")
+    temperature_c: float = Field(description="Temperature in Celsius")
+    conditions: str = Field(description="Weather summary")
+
+# Один вызов -- и модель возвращает типизированный Pydantic-объект
+model = init_chat_model("openai:gpt-4.1-mini")
+structured = model.with_structured_output(Weather)
+
+result: Weather = structured.invoke("Weather in Paris?")
+print(result.city, result.temperature_c, result.conditions)
+
+# method="json_mode" -- если провайдер не поддерживает tool calling
+# structured_json = model.with_structured_output(Weather, method="json_mode")

examples/slide-013/script.py

@@ -0,0 +1,57 @@
+"""
+Slide 13: | -- декларативная композиция
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-13.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-013/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 13 ===
+from langchain_core.prompts import ChatPromptTemplate
+from langchain_core.output_parsers import StrOutputParser
+from langchain.chat_models import init_chat_model
+
+prompt = ChatPromptTemplate.from_messages([
+    ("system", "You are a {style} assistant."),
+    ("human", "{question}"),
+])
+model = init_chat_model("openai:gpt-4.1-mini")
+
+# prompt, model, parser -- все три реализуют Runnable
+# Оператор | склеивает их в один chain
+chain = prompt | model | StrOutputParser()
+
+# type(chain) -> RunnableSequence
+print(type(chain).__name__)
+
+# invoke -> dict на вход, str на выход
+print(chain.invoke({"style": "concise", "question": "What is LCEL?"}))

examples/slide-014/script.py

@@ -0,0 +1,54 @@
+"""
+Slide 14: invoke / batch / stream -- без смены кода
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-14.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-014/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 14 ===
+chain = prompt | model | StrOutputParser()
+
+# 1. invoke -- один вход, один выход
+out_one = chain.invoke({"language": "French", "text": "Good morning"})
+
+# 2. batch -- список входов, список выходов (параллельно)
+out_many = chain.batch([
+    {"language": "French",  "text": "Good morning"},
+    {"language": "German",  "text": "Good morning"},
+    {"language": "Spanish", "text": "Good morning"},
+])
+print(out_many)  # ["Bonjour", "Guten Morgen", "Buenos dias"]
+
+# 3. stream -- итератор по чанкам (стримит последний Runnable)
+for chunk in chain.stream({"language": "French", "text": "Stream me"}):
+    print(chunk, end="", flush=True)

examples/slide-015/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 15: async + config -- полный контроль
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-15.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-015/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 15 ===
+import asyncio
+from langchain_core.runnables import ConfigurableField
+
+# Любой Runnable имеет ainvoke / astream / abatch
+async def main():
+    # Один async-вызов
+    result = await chain.ainvoke({"language": "French", "text": "Hi"})
+
+    # Async stream
+    async for chunk in chain.astream({"language": "French", "text": "Hi"}):
+        print(chunk, end="", flush=True)
+
+asyncio.run(main())
+
+# configurable_fields -- параметры, которые можно переопределять
+# на лету через config={"configurable": {...}}
+configurable_chain = init_chat_model("openai:gpt-4.1-mini",
+    temperature=0.7).configurable_fields(
+    temperature=ConfigurableField(id="temperature"),
+)
+# configurable_chain.invoke(messages, config={"configurable": {"temperature": 0.0}})

examples/slide-016/script.py

@@ -0,0 +1,57 @@
+"""
+Slide 16: RunnableLambda + RunnablePassthrough
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-16.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-016/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 16 ===
+from langchain_core.runnables import RunnableLambda, RunnablePassthrough
+
+# RunnableLambda -- оборачивает произвольную функцию
+upper = RunnableLambda(lambda x: x.upper())
+word_count = RunnableLambda(lambda text: {"text": text, "words": len(text.split())})
+
+# RunnablePassthrough -- пропускает вход дальше (для branching)
+passthrough = RunnablePassthrough()
+
+# Пример: текст -> uppercase -> посчитать слова -> смёрджить с оригиналом
+chain = (
+    word_count
+    | RunnablePassthrough.assign(upper=upper)
+)
+
+result = chain.invoke("hello world from langchain")
+print(result)
+# {"text": "hello world from langchain",
+#  "words": 4, "upper": "HELLO WORLD FROM LANGCHAIN"}

examples/slide-017/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 17: Parallel + Branch -- fan-out и роутинг
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-17.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-017/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 17 ===
+from langchain_core.runnables import RunnableParallel, RunnableBranch
+
+# Parallel -- один вход, несколько параллельных Runnable-ов, dict на выходе
+joke_chain = ChatPromptTemplate.from_template("Tell a joke about {topic}") | model
+poem_chain = ChatPromptTemplate.from_template("Write a poem about {topic}") | model
+
+parallel = RunnableParallel(joke=joke_chain, poem=poem_chain)
+result = parallel.invoke({"topic": "cats"})
+print(result.keys())  # dict_keys(["joke", "poem"])
+
+# Branch -- if/else роутинг по условию
+branch = RunnableBranch(
+    (lambda x: "code" in x["topic"].lower(), code_chain),
+    (lambda x: "math" in x["topic"].lower(), math_chain),
+    general_chain,  # default
+)
+print(branch.invoke({"topic": "code review"}))

examples/slide-018/script.py

@@ -0,0 +1,63 @@
+"""
+Slide 18: Vector store -> retriever -> RAG-цепочка
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-18.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-018/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 18 ===
+from langchain_openai import OpenAIEmbeddings
+from langchain_community.vectorstores import FAISS
+from langchain_core.runnables import RunnablePassthrough
+
+# 1. Эмбеддинги и индекс
+embeddings = OpenAIEmbeddings(model="text-embedding-3-small")
+docs = ["Cats are mammals.", "Python is a programming language.",
+        "LangChain helps build LLM apps."]
+vectorstore = FAISS.from_texts(docs, embedding=embeddings)
+
+# 2. .as_retriever() превращает store в Runnable
+retriever = vectorstore.as_retriever(search_kwargs={"k": 2})
+
+# 3. RAG-цепочка через LCEL: context + question -> answer
+from langchain_core.prompts import ChatPromptTemplate
+from langchain.chat_models import init_chat_model
+
+prompt = ChatPromptTemplate.from_template(
+    "Answer based on context.\nContext: {context}\nQ: {question}"
+)
+model = init_chat_model("openai:gpt-4.1-mini")
+rag = (
+    {"context": retriever, "question": RunnablePassthrough()}
+    | prompt | model | StrOutputParser()
+)

examples/slide-019/script.py

@@ -0,0 +1,58 @@
+"""
+Slide 19: @tool -- любая функция становится инструментом
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-19.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-019/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 19 ===
+from langchain.tools import tool
+from langchain.chat_models import init_chat_model
+
+@tool
+def get_weather(city: str) -> str:
+    """Get the current weather for a given city."""
+    return f"Sunny, 22C in {city}"
+
+@tool
+def search_docs(query: str, top_k: int = 3) -> list[str]:
+    """Search internal documentation. Returns top_k snippets."""
+    return [f"doc about {query} #{i}" for i in range(top_k)]
+
+# bind_tools -- модель знает, какие функции можно вызвать
+model = init_chat_model("openai:gpt-4.1-mini")
+bound = model.bind_tools([get_weather, search_docs])
+
+result = bound.invoke("What is the weather in Paris?")
+print(result.tool_calls)
+# [{"name": "get_weather", "args": {"city": "Paris"}, "id": "..."}]

examples/slide-020/script.py

@@ -0,0 +1,57 @@
+"""
+Slide 20: create_agent -- один вход для всех агентов
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-20.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-020/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 20 ===
+from langchain.agents import create_agent
+from langchain.tools import tool
+
+@tool
+def get_weather(city: str) -> str:
+    """Get weather for a city."""
+    return f"Sunny, 22C in {city}"
+
+# Один вызов вместо create_react_agent / create_openai_functions_agent / ...
+agent = create_agent(
+    model="openai:gpt-4.1",
+    tools=[get_weather],
+    system_prompt="You are a weather assistant.",
+)
+
+# invoke -> dict {"messages": [...]}; последнее сообщение = ответ
+result = agent.invoke({"messages": [{"role": "user",
+    "content": "weather in Paris?"}]})
+print(result["messages"][-1].content)

examples/slide-021/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 21: Краткосрочная память: thread + checkpointer
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-21.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-021/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 21 ===
+from langchain.agents import create_agent
+from langgraph.checkpoint.memory import InMemorySaver
+
+checkpointer = InMemorySaver()
+
+agent = create_agent(
+    model="openai:gpt-4.1-mini",
+    tools=[...],
+    checkpointer=checkpointer,  # <-- persistent state
+)
+
+config = {"configurable": {"thread_id": "user-42"}}
+
+# Первый turn
+agent.invoke({"messages": [{"role": "user",
+    "content": "My name is Alice."}]}, config=config)
+
+# Второй turn -- модель помнит имя
+result = agent.invoke({"messages": [{"role": "user",
+    "content": "What is my name?"}]}, config=config)
+print(result["messages"][-1].content)  # "Alice"

examples/slide-022/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 22: Долгосрочная память: store + namespace
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-22.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-022/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 22 ===
+from langgraph.store.memory import InMemoryStore
+from langchain.agents import create_agent
+from langchain.embeddings import init_embeddings
+
+# Store может быть in-memory (dev) или Postgres (prod)
+store = InMemoryStore(
+    index={"embed": init_embeddings("openai:text-embedding-3-small"),
+           "dims": 1536},
+)
+
+agent = create_agent(
+    model="openai:gpt-4.1-mini",
+    tools=[...],
+    store=store,
+)
+
+# Namespace = ("user-id", "facts") -- разделение по пользователям
+ns = ("user-42", "facts")
+store.put(ns, "pref-1", {"text": "User prefers concise answers."})
+
+# В новой сессии store.search(ns, query="preferences") вернёт факты

examples/slide-023/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 23: Cross-cutting concerns одной строкой
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-23.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-023/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 23 ===
+from langchain.agents import create_agent
+from langchain.agents.middleware import (
+    HumanInTheLoopMiddleware,
+    PIIRedactionMiddleware,
+    SummarizationMiddleware,
+)
+from langchain.tools import tool
+
+@tool
+def send_email(to: str, body: str) -> str:
+    """Send an email to recipient."""
+    return f"sent to {to}"
+
+agent = create_agent(
+    model="openai:gpt-4.1",
+    tools=[send_email],
+    middleware=[
+        HumanInTheLoopMiddleware(interrupt_on={"send_email": True}),
+        PIIRedactionMiddleware(redact_emails=True, redact_phones=True),
+        SummarizationMiddleware(trigger=("tokens", 4000)),
+    ],
+)

examples/slide-024/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 24: Что нового в 1.0 vs 0.3
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-24.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-024/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 24: Что нового в 1.0 vs 0.3')

examples/slide-025/script.py

@@ -0,0 +1,54 @@
+"""
+Slide 25: JS-аналог: что есть, чего нет
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-25.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-025/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 25 ===
+import { initChatModel } from "langchain/chat_models/universal";
+import { createAgent } from "langchain/agents";
+import { tool } from "@langchain/core/tools";
+import { z } from "zod";
+
+const getWeather = tool(
+  async ({ city }) => `Sunny, 22C in ${city}`,
+  { name: "get_weather", description: "Get weather",
+    schema: z.object({ city: z.string() }) },
+);
+
+const model = await initChatModel("openai:gpt-4.1");
+const agent = createAgent({ model, tools: [getWeather] });
+const result = await agent.invoke({
+  messages: [{ role: "user", content: "weather in Paris?" }],
+});

examples/slide-026/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 26: Когда LangChain 1.0 -- правильный выбор
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-26.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-026/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 26: Когда LangChain 1.0 -- правильный выбор')

examples/slide-027/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 27: Дальше: LangGraph -- явный control flow
+Section 1: LangChain 1.0
+Source: slides/section1-chains/slide-27.js
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-027/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 27: Дальше: LangGraph -- явный control flow')

examples/slide-028/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 28: LangGraph 1.0: stateful runtime
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-028/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 28: LangGraph 1.0: stateful runtime')

examples/slide-029/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 29: Slide 2
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-029/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 29: Slide 2')

examples/slide-030/script.py

@@ -0,0 +1,46 @@
+"""
+Slide 30: Slide 3
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-030/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 30 ===
+  pip install -U langgraph
+
+  # extras: postgres / sqlite checkpointers -- отдельные пакеты
+  pip install -U langgraph langgraph-checkpoint-postgres
+  pip install -U langgraph langgraph-checkpoint-sqlite
+
+  # JS / TypeScript
+  npm install @langchain/langgraph @langchain/langgraph-checkpoint

examples/slide-031/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 31: Slide 4
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-031/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 31 ===
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+> class State(TypedDict):
+>     question: str
+>     answer:   str
+      steps:    int
+
+  def answer(state: State) -> dict:
+      return {"answer": f"echo: {state['question']}", "steps": 1}
+
+  builder = StateGraph(State)
+  builder.add_node("answer", answer)
+  builder.add_edge(START, "answer")
+  builder.add_edge("answer", END)
+  graph = builder.compile()
+>  
+> print(graph.invoke({"question": "hi", "steps": 0}))
+> # -> {'question': 'hi', 'answer': 'echo: hi', 'steps': 1}
+
+// note: snippet has 19 lines, card fits ~17

examples/slide-032/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 32: Slide 5
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-032/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 32 ===
+  from typing import Annotated
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.graph.message import add_messages
+
+  class State(TypedDict):
+      # reducer add_messages склеивает списки сообщений по правилам
+>     messages: Annotated[list, add_messages]
+
+  def echo(state: State):
+      last = state["messages"][-1]
+>     return {"messages": [{"role": "assistant", "content": f"echo: {last.content}"}]}
+>  
+  g = StateGraph(State)
+  g.add_node("echo", echo)
+  g.add_edge(START, "echo")
+  g.add_edge("echo", END)
+  app = g.compile()
+
+  print(app.invoke({"messages": [{"role": "user", "content": "hi"}]}))
+
+// note: snippet has 20 lines, card fits ~18

examples/slide-033/script.py

@@ -0,0 +1,65 @@
+"""
+Slide 33: Slide 6
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-033/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 33 ===
+  import operator
+  from typing import Annotated
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+  class State(TypedDict):
+      # каждый узел возвращает кусок списка, operator.add склеивает
+      log:    Annotated[list[str], operator.add]
+>     tokens: Annotated[int,   operator.add]
+>  
+  def step(state: State):
+      return {"log": ["step-1"], "tokens": 12}
+
+  def another(state: State):
+      return {"log": ["step-2"], "tokens": 7}
+
+  g = StateGraph(State)
+  g.add_node("a", step)
+  g.add_node("b", another)
+  g.add_edge(START, "a")
+  g.add_edge("a", "b")
+  g.add_edge("b", END)
+  app = g.compile()
+  print(app.invoke({"log": [], "tokens": 0}))
+  # -> {'log': ['step-1', 'step-2'], 'tokens': 19}
+
+// note: snippet has 25 lines, card fits ~18

examples/slide-034/script.py

@@ -0,0 +1,61 @@
+"""
+Slide 34: Slide 7
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-034/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 34 ===
+  from dataclasses import dataclass, field
+  from typing import Annotated
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.graph.message import add_messages
+
+  @dataclass
+  class State:
+      question:  str = ""
+>     # dataclass + Annotated -- каналы работают точно так же
+>     messages:  Annotated[list, add_messages] = field(default_factory=list)
+      approved:  bool = False
+
+  def greet(state: State):
+      return {"messages": [{"role": "assistant", "content": f"hi, {state.question}"}]}
+
+  g = StateGraph(State)
+  g.add_node("greet", greet)
+  g.add_edge(START, "greet")
+  g.add_edge("greet", END)
+  app = g.compile()
+  print(app.invoke(State(question="alex")))
+
+// note: snippet has 21 lines, card fits ~18

examples/slide-035/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 35: Slide 8
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-035/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 35 ===
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+  class State(TypedDict):
+      n: int
+
+  def inc(state: State):
+      return {"n": state["n"] + 1}
+
+  builder = StateGraph(State)
+  builder.add_node("inc", inc)        # регистрируем узел
+> builder.add_edge(START, "inc")      # поток входа
+> builder.add_edge("inc", END)        # поток выхода
+>  
+  graph = builder.compile()           # компиляция -- граф готов к invoke
+
+> print(graph.invoke({"n": 0}))       # -> {'n': 1}

examples/slide-036/script.py

@@ -0,0 +1,61 @@
+"""
+Slide 36: Slide 9
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-036/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 36 ===
+  # START и END -- это специальные sentinel-узлы, не callable
+  from langgraph.graph import StateGraph, START, END
+>  
+  class State(TypedDict):
+      text: str
+
+  def upper(state: State):
+      return {"text": state["text"].upper()}
+
+  def exclaim(state: State):
+      return {"text": state["text"] + "!"}
+
+  g = StateGraph(State)
+> g.add_node("upper",   upper)
+  g.add_node("exclaim", exclaim)
+> g.add_edge(START, "upper")         # вход в граф
+> g.add_edge("upper",   "exclaim")   # внутреннее ребро
+  g.add_edge("exclaim", END)         # выход из графа
+
+  app = g.compile()
+  print(app.invoke({"text": "hi"}))  # -> {'text': 'HI!'}
+
+// note: snippet has 21 lines, card fits ~18

examples/slide-037/script.py

@@ -0,0 +1,64 @@
+"""
+Slide 37: Slide 10
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-037/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 37 ===
+  import asyncio
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+  class State(TypedDict):
+      out: str
+
+  def sync_node(state: State):                 # обычная функция
+      return {"out": "sync-ok"}
+
+> async def async_node(state: State):          # async тоже работает
+      await asyncio.sleep(0)
+>     return {"out": "async-ok"}
+
+  g = StateGraph(State)
+  g.add_node("s", sync_node)
+  g.add_node("a", async_node)
+  g.add_edge(START, "s")
+  g.add_edge("s", "a")
+  g.add_edge("a", END)
+  app = g.compile()
+
+  print(app.invoke({"out": ""}))
+  print(asyncio.run(app.ainvoke({"out": ""})))
+
+// note: snippet has 24 lines, card fits ~18

examples/slide-038/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 38: Slide 11
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-038/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 38 ===
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.types import Command
+  from typing_extensions import TypedDict
+  from typing import Literal
+  class State(TypedDict):
+      n: int
+> def decide(state: State) -> Command[Literal["inc", "halt"]]:
+>     # Command(update, goto) -- обновляет state и сам выбирает узел
+      if state["n"] < 3:
+>         return Command(update={"n": state["n"] + 1}, goto="inc")
+      return Command(update={}, goto="halt")
+  g = StateGraph(State)
+  g.add_node("decide", decide)
+  g.add_node("inc",    inc)
+  g.add_node("halt",   lambda s: s)
+  g.add_edge(START, "decide")
+  g.add_edge("inc", "decide")
+  g.add_edge("halt", END)
+  app = g.compile()
+  print(app.invoke({"n": 0}))
+
+// note: snippet has 20 lines, card fits ~18

examples/slide-039/script.py

@@ -0,0 +1,68 @@
+"""
+Slide 39: Slide 12
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-039/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 39 ===
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+  class State(TypedDict):
+      needs_tool: bool
+      answer: str
+
+  def agent(state: State) -> dict:
+      return {"answer": "model-output"}
+
+  def tool_node(state: State) -> dict:
+      return {"answer": "tool-output"}
+
+  def route(state: State) -> str:
+      # возвращаем ключ, который есть в path_map ниже
+      return "tool_node" if state["needs_tool"] else END
+
+  g = StateGraph(State)
+> g.add_node("agent",     agent)
+> g.add_node("tool_node", tool_node)
+> g.add_edge(START, "agent")
+> g.add_conditional_edges("agent", route, {
+>     "tool_node": "tool_node",
+      END: END,
+  })
+  g.add_edge("tool_node", END)
+  app = g.compile()
+  print(app.invoke({"needs_tool": True, "answer": ""}))
+
+// note: snippet has 28 lines, card fits ~18

examples/slide-040/script.py

@@ -0,0 +1,61 @@
+"""
+Slide 40: Slide 13
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-040/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 40 ===
+  # агентный цикл: agent <-> tools, выход когда done=true
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+  class State(TypedDict):
+      done: bool
+      iter: int
+
+  def agent(state: State) -> dict:
+      return {"iter": state["iter"] + 1, "done": state["iter"] >= 3}
+
+  def maybe_continue(state: State) -> str:
+      return "agent" if not state["done"] else END
+
+> g = StateGraph(State)
+> g.add_node("agent", agent)
+  g.add_edge(START, "agent")
+  g.add_conditional_edges("agent", maybe_continue, {"agent": "agent", END: END})
+  app = g.compile()
+  print(app.invoke({"done": False, "iter": 0}))
+  # agent крутится 3 раза, потом уходит в END
+
+// note: snippet has 21 lines, card fits ~18

examples/slide-041/script.py

@@ -0,0 +1,66 @@
+"""
+Slide 41: Slide 14
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-041/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 41 ===
+  from typing import Annotated
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.graph.message import add_messages
+  from langgraph.checkpoint.memory import InMemorySaver
+
+  class State(TypedDict):
+      messages: Annotated[list, add_messages]
+
+  def echo(state: State):
+      last = state["messages"][-1]
+      return {"messages": [{"role": "assistant", "content": f"echo: {last.content}"}]}
+
+  g = StateGraph(State)
+  g.add_node("echo", echo)
+  g.add_edge(START, "echo")
+  g.add_edge("echo", END)
+
+  # checkpointer -- обязателен для thread persistence
+  checkpointer = InMemorySaver()
+  app = g.compile(checkpointer=checkpointer)
+>  
+> cfg = {"configurable": {"thread_id": "user-1"}}
+  app.invoke({"messages": [{"role": "user", "content": "hi"}]},   cfg)
+> app.invoke({"messages": [{"role": "user", "content": "again"}]}, cfg)
+> # второй вызов видит все сообщения первого: thread persistence работает
+
+// note: snippet has 26 lines, card fits ~18

examples/slide-042/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 42: Slide 15
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-042/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 42 ===
+> # SQLite -- файл на диске, идеален для dev / small-prod
+  from langgraph.checkpoint.sqlite import SqliteSaver
+>  
+> with SqliteSaver.from_conn_string("./checkpoints.db") as cp:
+>     app = g.compile(checkpointer=cp)
+      cfg = {"configurable": {"thread_id": "u1"}}
+      app.invoke({"messages": []}, cfg)
+
+  # данные переживают рестарт процесса.
+  # Для asyncio-варианта -- aiosqlite.
+
+> # Postgres -- production-grade, multi-instance
+  from langgraph.checkpoint.postgres import PostgresSaver
+>  
+  DB = "postgresql://user:pass@host:5432/lg"
+  with PostgresSaver.from_conn_string(DB) as cp:
+>     # первый запуск создаст schema
+      cp.setup()
+      app = g.compile(checkpointer=cp)
+      cfg = {"configurable": {"thread_id": "u1"}}
+      app.invoke({"messages": []}, cfg)

examples/slide-043/script.py

@@ -0,0 +1,50 @@
+"""
+Slide 43: Slide 16
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-043/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 43 ===
+  # После invoke можно достать текущий snapshot:
+> snapshot = app.get_state(cfg)
+
+  # snapshot -- это StateSnapshot с полями:
+> #   .config     -- thread_id + checkpoint_id
+> #   .metadata   -- step, source, writes
+> #   .values     -- текущие значения всех каналов state
+> #   .next       -- tuple узлов, которые будут выполняться следующими
+> #   .tasks      -- PregelTask с pending/result/error
+
+  print(snapshot.next)        # ()  -- граф завершён
+  print(snapshot.values["messages"][-1].content)

examples/slide-044/script.py

@@ -0,0 +1,50 @@
+"""
+Slide 44: Slide 17
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-044/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 44 ===
+  # Каждый super-step -- отдельный checkpoint в thread
+> history = list(app.get_state_history(cfg))
+>  
+> # history[0]  -- последний шаг (самый свежий)
+  # history[-1] -- самый первый (начало сессии)
+
+> for i, snap in enumerate(history):
+      print(i, snap.metadata.get("step"), snap.values.get("iter"))
+
+> # replays = форк от любого прошлого snapshot:
+> old = history[2].config
+  app.invoke(None, old)   # переигрывает только следующие шаги

examples/slide-045/script.py

@@ -0,0 +1,50 @@
+"""
+Slide 45: Slide 18
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-045/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 45 ===
+  # patch значения канала прямо в snapshot -- создаётся новый checkpoint
+> app.update_state(
+>     cfg,
+>     values={"messages": [{"role": "user", "content": "rewind"}]},
+>     as_node="user_input",   # от имени какого узла пишем
+  )
+
+  # Дальше invoke(None, cfg) переигрывает граф с нового состояния
+  app.invoke(None, cfg)
+>  
+> # Типичный приём: "что если пользователь сказал не X, а Y?" --
+  # ответвляемся, смотрим альтернативный прогон без потери истории.

examples/slide-046/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 46: Slide 19
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-046/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 46 ===
+  from langgraph.types import interrupt, Command
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.checkpoint.memory import InMemorySaver
+  from typing_extensions import TypedDict
+  class State(TypedDict):
+      question: str
+      approved: bool
+  def ask(state: State):
+      # interrupt() -- пауза. Возвращает значение из Command(resume=...)
+>     answer = interrupt({"question": "Approve sending this message?"})
+      return {"approved": answer == "yes"}
+  g = StateGraph(State)
+  g.add_node("ask", ask)
+  g.add_edge(START, "ask")
+  g.add_edge("ask", END)
+  app = g.compile(checkpointer=InMemorySaver())
+> cfg = {"configurable": {"thread_id": "approval-1"}}
+> app.invoke({"question": "send email", "approved": False}, cfg)   # пауза
+> result = app.invoke(Command(resume="yes"), cfg)                  # resume
+  print(result["approved"])  # -> True
+
+// note: snippet has 20 lines, card fits ~18

examples/slide-047/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 47: Slide 20
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-047/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 47: Slide 20')

examples/slide-048/script.py

@@ -0,0 +1,56 @@
+"""
+Slide 48: Slide 21
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-048/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 48 ===
+  # Узел review -- маршрутизация по ответу человека
+  from langgraph.types import interrupt, Command
+  from typing_extensions import TypedDict
+  class State(TypedDict):
+      plan: str
+      executed: bool
+  def plan(state: State):
+      return {"plan": "step-A; step-B; step-C"}
+> def review(state: State) -> Command:
+>     # interrupt() возвращает ответ из Command(resume=...)
+>     decision = interrupt({"plan": state["plan"]})
+>     if decision == "approve":
+>         return Command(goto="execute")
+>     if decision == "abort":
+>         return Command(goto=END)
+      return Command(goto="plan")  # перепланировать
+  def execute(state: State):
+      return {"executed": True}

examples/slide-049/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 49: Slide 22
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-049/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 49 ===
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.checkpoint.memory import InMemorySaver
+  # plan, review, execute -- из предыдущего слайда
+  g = StateGraph(State)
+> g.add_node("plan",    plan)
+> g.add_node("review",  review)
+  g.add_node("execute", execute)
+> g.add_edge(START, "plan")
+  g.add_edge("plan", "review")
+  g.add_edge("execute", END)
+  app = g.compile(checkpointer=InMemorySaver())
+
+  # Цикл: каждый review -- это пауза; Command(goto=...) -- ответвление
+> # plan -> review -> (approve: execute | abort: END | else: plan)
+> cfg = {"configurable": {"thread_id": "u1"}}
+  app.invoke({"plan": "", "executed": False}, cfg)         # пауза 1
+  app.invoke(Command(resume="approve"), cfg)               # resume -> execute

examples/slide-050/script.py

@@ -0,0 +1,66 @@
+"""
+Slide 50: Slide 23
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-050/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 50 ===
+  from typing_extensions import TypedDict
+  from langgraph.graph import StateGraph, START, END
+
+  class SubState(TypedDict):
+      internal: str
+
+  def inner(state: SubState):
+      return {"internal": "sub-output"}
+
+  # Собираем subgraph -- у него свой state
+> sub = StateGraph(SubState)
+> sub.add_node("inner", inner)
+> sub.add_edge(START, "inner")
+> sub.add_edge("inner", END)
+  sub_compiled = sub.compile()
+
+  # Вставляем как обычный узел в родительский граф
+  class ParentState(TypedDict):
+      out: str
+
+> parent = StateGraph(ParentState)
+> parent.add_node("sub_block", sub_compiled)   # <- subgraph целиком
+  parent.add_edge(START, "sub_block")
+  parent.add_edge("sub_block", END)
+  app = parent.compile()
+  print(app.invoke({"out": ""}))
+
+// note: snippet has 26 lines, card fits ~18

examples/slide-051/script.py

@@ -0,0 +1,54 @@
+"""
+Slide 51: Slide 24
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-051/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 51 ===
+  cfg = {"configurable": {"thread_id": "u1"}}
+  # values    -- весь state после каждого super-step
+> for snap in app.stream({"messages": []}, cfg, stream_mode="values"):
+      print(snap["messages"][-1].content)
+  # updates   -- delta: только что вернул каждый узел
+> for upd in app.stream({"messages": []}, cfg, stream_mode="updates"):
+      print(upd)
+  # events    -- низкоуровневые события (start, end, error, interrupt)
+> for ev in app.stream({"messages": []}, cfg, stream_mode="events"):
+      print(ev["event"], ev["name"])
+  # messages  -- токены LLM по мере генерации
+> for tok, meta in app.stream({"messages": []}, cfg, stream_mode="messages"):
+      print(tok.content, end="|")
+  # custom    -- только то, что узлы пишут через get_stream_writer()
+> for chunk in app.stream({"messages": []}, cfg, stream_mode="custom"):
+      print(chunk)

examples/slide-052/script.py

@@ -0,0 +1,62 @@
+"""
+Slide 52: Slide 25
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-052/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 52 ===
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.config import get_stream_writer
+  from typing_extensions import TypedDict
+
+  class State(TypedDict):
+      total: int
+
+  def progress(state: State):
+      writer = get_stream_writer()      # доступен только во время выполнения узла
+>     for i in range(3):
+>         writer({"progress": i, "phase": "thinking"})
+>     return {"total": 3}
+
+  g = StateGraph(State)
+  g.add_node("progress", progress)
+  g.add_edge(START, "progress")
+  g.add_edge("progress", END)
+  app = g.compile()
+>  
+> # в UI -- только custom-чанки, без промежуточного state
+  for chunk in app.stream({"total": 0}, stream_mode="custom"):
+      print(chunk)
+
+// note: snippet has 22 lines, card fits ~18

examples/slide-053/script.py

@@ -0,0 +1,56 @@
+"""
+Slide 53: Slide 26
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-053/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 53 ===
+  from langchain_openai import ChatOpenAI
+  from langchain.tools import tool
+  from langgraph.graph.message import add_messages
+  from typing import Annotated
+  from typing_extensions import TypedDict
+  @tool
+  def add(a: int, b: int) -> int:
+      "Add two numbers."
+      return a + b
+  tools = [add]
+> llm = ChatOpenAI(model="gpt-4o-mini").bind_tools(tools)
+  class State(TypedDict):
+      messages: Annotated[list, add_messages]
+  def agent(state: State):
+      return {"messages": [llm.invoke(state["messages"])]}
+  def route(state: State) -> str:
+>     last = state["messages"][-1]
+      return "tools" if getattr(last, "tool_calls", None) else END

examples/slide-054/script.py

@@ -0,0 +1,54 @@
+"""
+Slide 54: Slide 27
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-054/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 54 ===
+  from langgraph.graph import StateGraph, START, END
+  from langgraph.prebuilt import ToolNode
+  # tools, llm, agent, route -- из предыдущего слайда
+  g = StateGraph(State)
+  g.add_node("agent", agent)
+> g.add_node("tools", ToolNode(tools))
+  g.add_edge(START, "agent")
+  g.add_conditional_edges("agent", route, {"tools": "tools", END: END})
+  g.add_edge("tools", "agent")
+> app = g.compile()
+
+  # Цикл: agent решает -> tools исполняет -> agent снова читает результат
+> result = app.invoke({
+>     "messages": [{"role": "user", "content": "What is 2 + 3?"}]
+  })
+  print(result["messages"][-1].content)

examples/slide-055/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 55: Slide 28
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-055/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 55 ===
+  # запуск: langgraph dev  -- поднимает Studio на http://localhost:8123

examples/slide-056/script.py

@@ -0,0 +1,49 @@
+"""
+Slide 56: Slide 29
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-056/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 56 ===
+  # langgraph.json -- declarative config
+> {
+    "graphs": {"agent": "./agent.py:graph"},
+    "env":  "./.env",
+    "python_version": "3.11"
+  }
+
+  # CLI: локальный dev-сервер и deploy
+  langgraph dev       # локальный API + Studio
+> langgraph up        # Docker-compose stack (Redis + API + Studio)
+  langgraph deploy    # пуш в LangGraph Platform (managed)

examples/slide-057/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 57: Slide 30
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-057/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 57: Slide 30')

examples/slide-058/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 58: Slide 31
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-058/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 58 ===
+> import { StateGraph, START, END, Annotation } from "@langchain/langgraph";
+> import { MemorySaver }               from "@langchain/langgraph-checkpoint";
+
+  const State = Annotation.Root({
+    messages: Annotation({
+      reducer: (a, b) => a.concat(b),
+      default: () => [],
+    }),
+  });
+
+  const g = new StateGraph(State)
+    .addNode("echo", (s) => ({
+      messages: [{ role: "assistant", content: "echo: " + s.messages.at(-1).content }],
+    }))
+    .addEdge(START, "echo")
+    .addEdge("echo", END);
+
+  const app = g.compile({ checkpointer: new MemorySaver() });
+> const cfg = { configurable: { thread_id: "t1" } };
+  const result = await app.invoke({ messages: [{ role: "user", content: "hi" }] }, cfg);
+
+// note: snippet has 20 lines, card fits ~18

examples/slide-059/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 59: Slide 32
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-059/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 59: Slide 32')

examples/slide-060/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 60: Slide 33
+Section 2: LangGraph 1.0
+Source: slides/section2-langgraph/section2.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-060/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 60: Slide 33')

examples/slide-061/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 61: Deep Agents 1.0
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-061/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 61: Deep Agents 1.0')

examples/slide-062/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 62: Slide 2
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-062/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 62: Slide 2')

examples/slide-063/script.py

@@ -0,0 +1,56 @@
+"""
+Slide 63: Slide 3
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-063/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 63 ===
+// examples/hello.py:1-14
+
+  # One import, one call -- you get:
+  #  - write_todos planning tool
+  #  - ls / read_file / write_file / edit_file
+  #  - glob, grep, execute (bash)
+  #  - task tool for subagents
+  #  - summarization middleware
+
+  from deepagents import create_deep_agent
+>  
+> agent = create_deep_agent(
+>     model="openai:gpt-4.1",
+>     tools=[my_tool],
+>     system_prompt="...",
+> )
+
+// note: snippet has 14 lines, card fits ~10

examples/slide-064/script.py

@@ -0,0 +1,47 @@
+"""
+Slide 64: Slide 4
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-064/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 64 ===
+// setup.sh:1-5
+
+  pip install deepagents
+  # or, with uv:
+  uv add deepagents
+  # JS analogue:
+  npm install deepagents
+
+// note: snippet has 5 lines, card fits ~3

examples/slide-065/script.py

@@ -0,0 +1,52 @@
+"""
+Slide 65: Slide 5
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-065/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 65 ===
+// examples/hello.py:1-12
+
+  from deepagents import create_deep_agent
+
+> agent = create_deep_agent(
+>     model="openai:gpt-4.1",
+>     tools=[],
+>     system_prompt="You are a helpful assistant.",
+  )
+
+  result = agent.invoke({
+      "messages": "Write a haiku about Python"
+  })
+  print(result["messages"][-1].content)

examples/slide-066/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 66: Slide 6
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-066/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 66 ===
+// examples/full_api.py:1-15
+
+  from deepagents import create_deep_agent
+  from deepagents.backends import FilesystemBackend
+
+> agent = create_deep_agent(
+>     model="anthropic:claude-sonnet-4-5",
+>     tools=[my_tool],
+>     system_prompt="...",
+>     subagents=[researcher, writer],
+>     skills=["./skills/review.md"],
+>     backend=FilesystemBackend("./ws"),
+>     middleware=[my_hitl, my_logger],
+>     checkpointer=InMemorySaver(),
+>     store=InMemoryStore(),
+>     interrupt_on={"bash": True},
+  )

examples/slide-067/script.py

@@ -0,0 +1,56 @@
+"""
+Slide 67: Slide 7
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-067/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 67 ===
+// examples/system_prompt.py:1-16
+
+  SYSTEM_PROMPT = """
+  You are a senior backend engineer.
+
+> WORKFLOW:
+>   1. Plan with write_todos before non-trivial work.
+>   2. Explore the codebase via ls / glob / grep first.
+>   3. Use edit_file for surgical changes, write_file for new files.
+>   4. Delegate research tasks to the "researcher" subagent.
+    5. Run tests via execute; never claim success without output.
+
+  CONSTRAINTS:
+>   - Do not modify files outside ./src.
+>   - Stop and ask the user if requirements are ambiguous.
+  """
+
+  agent = create_deep_agent(model=..., system_prompt=SYSTEM_PROMPT)

examples/slide-068/script.py

@@ -0,0 +1,55 @@
+"""
+Slide 68: Slide 8
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-068/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 68 ===
+write_todos
+
+ls
+
+read_file
+
+write_file
+
+edit_file
+
+glob
+
+grep
+
+execute
+
+task

examples/slide-069/script.py

@@ -0,0 +1,51 @@
+"""
+Slide 69: Slide 9
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-069/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 69 ===
+// examples/fs_tools.py:1-11
+
+  # The agent calls these tools by name;
+  # you describe the goal in the prompt.
+
+> PROMPT = """
+> 1. Write src/hello.py with a greet(name) function.
+> 2. Use edit_file to add a docstring to greet().
+> 3. Use write_file to add tests/test_hello.py.
+  """
+
+  agent = create_deep_agent(model="openai:gpt-4.1")
+  agent.invoke({"messages": PROMPT})

examples/slide-070/script.py

@@ -0,0 +1,54 @@
+"""
+Slide 70: Slide 10
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-070/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 70 ===
+// examples/write_todos.py:1-12
+
+  write_todos(
+>     todos=[
+>         {"content": "Read repo structure", "status": "in_progress",
+>          "activeForm": "Reading repo structure"},
+>         {"content": "Implement greet()",      "status": "pending",
+>          "activeForm": "Implementing greet()"},
+>         {"content": "Add pytest cases",       "status": "pending",
+>          "activeForm": "Adding pytest cases"},
+>     ]
+  )
+  # Status: pending | in_progress | completed
+  # activeForm: present-continuous shown in UI
+
+// note: snippet has 12 lines, card fits ~10

examples/slide-071/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 71: Slide 11
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-071/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 71: Slide 11')

examples/slide-072/script.py

@@ -0,0 +1,50 @@
+"""
+Slide 72: Slide 12
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-072/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 72 ===
+// examples/task_call.py:1-10
+
+  # When the main agent emits a tool call like:
+> task(
+>     subagent_type="researcher",
+>     description="Find papers on RAG evaluation",
+>     prompt="Search arXiv for 2025-2026 RAG evaluation surveys. 
+>              Return a 150-word summary with 3 citations.",
+  )
+
+  # Deep Agents spins up a fresh deep agent with the researcher profile,
+  # runs it to completion, and returns only the final message.

examples/slide-073/script.py

@@ -0,0 +1,65 @@
+"""
+Slide 73: Slide 13
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-073/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 73 ===
+// examples/subagents.py:1-23
+
+  from deepagents import create_deep_agent
+
+  researcher = {
+>     "name": "researcher",
+>     "description": "Does deep web research, returns citations",
+>     "system_prompt": "You are a research specialist. Always cite sources.",
+>     "tools": [web_search],  # optional, can be []
+  }
+
+  writer = {
+>     "name": "writer",
+>     "description": "Polishes prose into a final report",
+>     "system_prompt": "You are a writing specialist.",
+>     "tools": [],
+  }
+
+  agent = create_deep_agent(
+      model="openai:gpt-4.1",
+>     tools=[],
+>     subagents=[researcher, writer],
+> )
+>  
+  agent.invoke({"messages": "Research quantum computing and write a 200-word summary."})
+
+// note: snippet has 23 lines, card fits ~16

examples/slide-074/script.py

@@ -0,0 +1,58 @@
+"""
+Slide 74: Slide 14
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-074/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 74 ===
+context = [
+  user task,
+  summary from researcher,
+  summary from writer
+]
+
+task("researcher")
+
+context = [
+  full web_search results,
+  all 14 sources,
+  notes, drafts, citations
+]
+return: 150-word summary
+
+context = [
+  researcher summary,
+  original user task
+]
+return: polished 200-word report

examples/slide-075/script.py

@@ -0,0 +1,49 @@
+"""
+Slide 75: Slide 15
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-075/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 75 ===
+// examples/virtual_fs.py:1-9
+
+  # Inspect the virtual filesystem after a run:
+  result = agent.invoke({"messages": "Summarize repo"})
+>  
+> files = result.get("files", {})
+> for path, doc in files.items():
+>     print(f"{path}: {len(doc.get('content', []))} bytes")
+
+  # /repo/src/main.py: 421 bytes
+  # /repo/README.md:   1804 bytes

examples/slide-076/script.py

@@ -0,0 +1,45 @@
+"""
+Slide 76: Slide 16
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-076/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 76 ===
+before_model
+
+after_model
+
+before_tool
+
+after_tool

examples/slide-077/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 77: Slide 17
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-077/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 77 ===
+// examples/middleware.py:1-18
+
+  from langchain.agents.middleware import AgentMiddleware
+  from deepagents import create_deep_agent
+
+  class LoggerMiddleware(AgentMiddleware):
+>     def before_model(self, state, runtime):
+>         print(f"[model] {len(state['messages'])} msgs in")
+>         return state
+>  
+>     def after_tool(self, state, runtime, tool_result):
+>         print(f"[tool]  {tool_result.tool_call_id} -> {len(str(tool_result.content))} chars")
+          return state
+
+  agent = create_deep_agent(
+      model="openai:gpt-4.1",
+      middleware=[LoggerMiddleware(), HumanInTheLoopMiddleware(
+>         interrupt_on={"execute": True},  # ask before running bash
+>     )],
+> )
+
+// note: snippet has 18 lines, card fits ~16

examples/slide-078/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 78: Slide 18
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-078/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 78: Slide 18')

examples/slide-079/script.py

@@ -0,0 +1,62 @@
+"""
+Slide 79: Slide 19
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-079/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 79 ===
+// examples/composite_backend.py:1-20
+
+  from deepagents import create_deep_agent
+  from deepagents.backends import (
+      CompositeBackend, FilesystemBackend, StoreBackend
+  )
+  from langgraph.store.memory import InMemoryStore
+
+  store = InMemoryStore()  # or PostgresStore in prod
+
+  backend = CompositeBackend(
+      default=FilesystemBackend(root_dir="./workspace"),
+      routes={
+>         "/memory/": StoreBackend(store=store, namespace=("agent", "kb")),
+>         "/scratch/": FilesystemBackend(root_dir="/tmp/scratch"),
+>     },
+> )
+
+  agent = create_deep_agent(model=..., backend=backend)
+  # /workspace/notes.md -> local disk
+  # /memory/lessons.md  -> Postgres, shared across sessions
+> # /scratch/tmp.py     -> ephemeral tmpfs
+
+// note: snippet has 20 lines, card fits ~16

examples/slide-080/script.py

@@ -0,0 +1,65 @@
+"""
+Slide 80: Slide 20
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-080/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 80 ===
+// examples/hitl.py:1-23
+
+  from langchain.agents.middleware import HumanInTheLoopMiddleware
+  from deepagents import create_deep_agent
+  from langgraph.checkpoint.memory import InMemorySaver
+  from langgraph.types import Command
+
+  agent = create_deep_agent(
+      model="openai:gpt-4.1",
+      checkpointer=InMemorySaver(),
+>     middleware=[HumanInTheLoopMiddleware(
+>         interrupt_on={
+>             "execute":   True,    # bash -- always ask
+>             "write_file": True,   # disk writes -- always ask
+>             "task":      False,   # subagents -- run unattended
+>         },
+      )],
+  )
+
+  cfg = {"configurable": {"thread_id": "user-42"}}
+  try:
+      agent.invoke({"messages": "deploy to staging"}, cfg)
+  except InterruptedError:
+      decision = ask_user("Approve execute()?")   # your UI
+      agent.invoke(Command(resume=decision), cfg)
+
+// note: snippet has 23 lines, card fits ~15

examples/slide-081/script.py

@@ -0,0 +1,60 @@
+"""
+Slide 81: Slide 21
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-081/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 81 ===
+// examples/streaming.py:1-18
+
+  cfg = {"configurable": {"thread_id": "user-42"}}
+
+  # 1. Stream model tokens as they arrive
+> for token, meta in agent.stream(
+>     {"messages": "..."}, cfg,
+>     stream_mode="messages",
+  ):
+      print(token.content, end="", flush=True)
+
+  # 2. Stream state updates per node
+  for chunk in agent.stream(
+>     {"messages": "..."}, cfg,
+>     stream_mode="updates",
+> ):
+      print(chunk)  # {"model": {...}, "tools": {...}}
+
+  # 3. Subagent streams are surfaced as
+  #    {"subagent": {"name": "researcher", "chunk": ...}}
+
+// note: snippet has 18 lines, card fits ~16

examples/slide-082/script.py

@@ -0,0 +1,48 @@
+"""
+Slide 82: Slide 22
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-082/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 82 ===
+// examples/langsmith.sh:1-8
+
+  export LANGSMITH_TRACING=true
+  export LANGSMITH_API_KEY=lsv2_...
+  export LANGSMITH_PROJECT=deepagents-evals
+
+  python my_deep_agent.py
+  # -> all runs visible in smith.langchain.com
+  # -> subagent runs nested under the parent
+  # -> token usage, latency, tool errors captured

examples/slide-083/script.py

@@ -0,0 +1,66 @@
+"""
+Slide 83: Slide 23
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-083/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 83 ===
+// examples/research_agent.py:1-24
+
+  from langchain.tools import tool
+  from deepagents import create_deep_agent
+
+  @tool
+  def arxiv_search(query: str, max_results: int = 5) -> str:
+      """Search arXiv for papers matching the query."""
+      import arxiv
+      client = arxiv.Client()
+      results = list(client.results(arxiv.Search(query=query, max_results=max_results)))
+      return "\n\n".join(
+          f"{r.title}\n{r.summary[:300]}..." for r in results
+      )
+
+  agent = create_deep_agent(
+      model="openai:gpt-4.1",
+      tools=[arxiv_search],
+      system_prompt=("You are a research assistant. Always cite paper titles and arXiv IDs."),
+>     subagents=[{
+>         "name": "summarizer",
+>         "description": "Compresses paper abstracts into a paragraph",
+>         "system_prompt": "You are a precise summarizer.",
+>         "tools": [],
+>     }],
+> )
+
+// note: snippet has 24 lines, card fits ~16

examples/slide-084/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 84: Slide 24
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-084/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 84 ===
+// examples/coding_agent.py:1-17
+
+  from deepagents import create_deep_agent
+  from deepagents.backends import SandboxBackend
+
+> agent = create_deep_agent(
+>     model="anthropic:claude-sonnet-4-5",
+>     backend=SandboxBackend(
+>         provider="daytona",       # or modal / runloop
+>         api_key=os.environ["DAYTONA_API_KEY"],
+>         image="python:3.12-slim",
+>     ),
+>     system_prompt=("You are a coding agent. Always run tests after edits. Stop and ask if requirements are ambiguous."),
+  )
+
+  agent.invoke({"messages": "Add a /healthz endpoint to the FastAPI app, with tests."})
+
+  # Daytona/Modal/Runloop execute code in an isolated container;
+  # the local process never sees a stray rm -rf.
+
+// note: snippet has 17 lines, card fits ~16

examples/slide-085/script.py

@@ -0,0 +1,53 @@
+"""
+Slide 85: Slide 25
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-085/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 85 ===
+// examples/deepagentsjs.ts:1-13
+
+  // TypeScript analogue (deepagentsjs)
+  import { createDeepAgent } from "deepagents";
+  import { tool, z } from "@langchain/core/tools";
+
+  const search = tool(
+    async ({ q }) => fetch("/api/search?q=" + q).then(r => r.text()),
+    { name: "search", schema: z.object({ q: z.string() }) },
+  );
+
+> const agent = await createDeepAgent({
+>   model: "openai:gpt-4.1",
+>   tools: [search],
+> });

examples/slide-086/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 86: Slide 26
+Section 3: Deep Agents
+Source: slides/section3-deepagents/section3.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-086/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 86: Slide 26')

examples/slide-087/script.py

@@ -0,0 +1,39 @@
+"""
+Slide 87: Open SWE: async coding agent
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-087/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# (No extractable code on this slide — visual-only or section divider)
+print('Slide 87: Open SWE: async coding agent')

examples/slide-088/script.py

@@ -0,0 +1,52 @@
+"""
+Slide 88: Slide 2
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-088/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 88 ===
+// meta: open-swe repo:1-12
+
+  # github.com/langchain-ai/open-swe
+
+  stars:    ~10k
+  commits:  971+
+  license:  MIT
+  language: Python + TypeScript
+  announce: 08.2025
+  rewrite:  03.2026
+
+  # blog.langchain.com/open-swe
+  # INSTALLATION.md
+  # CUSTOMIZATION.md

examples/slide-089/script.py

@@ -0,0 +1,65 @@
+"""
+Slide 89: Slide 3
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-089/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 89 ===
+Slack / Linear / GitHub / Web UI
+
+prompt + middleware (HITL, approval)
+
+subagents + middleware
+
+AGENTS.md из репозитория
+
+execute, fetch_url, linear_comment, slack_thread_reply
+
+Modal / Daytona / Runloop / LangSmith
+
+create_deep_agent (Deep Agents)
+
+// open_swe/__init__.py:1-11
+
+  from open_swe.agent import create_agent
+  from open_swe.middleware import (
+      check_message_queue_before_model,
+      notify_step_limit_reached,
+      open_pr_if_needed,
+      ToolErrorMiddleware,
+  )
+  from open_swe.sandbox import (
+      SandboxBackend,
+      ModalBackend, DaytonaBackend,
+  )

examples/slide-090/script.py

@@ -0,0 +1,51 @@
+"""
+Slide 90: Slide 4
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-090/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 90 ===
+// examples/minimal_agent.py:1-11
+
+  from deepagents import create_deep_agent
+  from open_swe.sandbox import DaytonaBackend
+
+> agent = create_deep_agent(
+      model="anthropic:claude-opus-4-6",
+      tools=[execute, fetch_url,
+             linear_comment,
+>            slack_thread_reply],
+>     backend=DaytonaBackend(api_key="..."),
+      middleware=[open_pr_if_needed],
+  )

examples/slide-091/script.py

@@ -0,0 +1,59 @@
+"""
+Slide 91: Slide 5
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-091/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 91 ===
+// open_swe/prompts.py:1-9
+
+  from pathlib import Path
+
+  def construct_system_prompt(
+      repo_dir, base_prompt
+  ):
+      agents_md = Path(repo_dir) / "AGENTS.md"
+      extra = agents_md.read_text() if
+          agents_md.exists() else ""
+      return base_prompt + extra
+
+// note: snippet has 9 lines, card fits ~6
+
+// AGENTS.md:1-5
+
+  # AGENTS.md  (repo root)
+
+  - use uv, not pip
+  - run pytest before commit
+  - never push to main directly

examples/slide-092/script.py

@@ -0,0 +1,53 @@
+"""
+Slide 92: Slide 6
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-092/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 92 ===
+// examples/audit_middleware.py:1-13
+
+  from langchain.agents.middleware import (
+      AgentMiddleware,
+  )
+
+> class AuditMiddleware(AgentMiddleware):
+>     def after_model(self, state, runtime):
+>         runtime.logger.info(
+>             f"step={state.get("step")}"
+          )
+          return state
+
+      def before_model(self, state, runtime):
+          return state  # inject reminder

examples/slide-093/script.py

@@ -0,0 +1,77 @@
+"""
+Slide 93: Slide 7
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-093/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 93 ===
+ModalBackend
+
+token_id + token_secret
+
+per-second + GB-s
+
+yes (volume)
+
+Python-first, GPU-доступный
+
+DaytonaBackend
+
+api_key
+
+per-session
+
+yes (volume)
+
+default в README
+
+RunloopBackend
+
+api_key
+
+per-second
+
+yes (volume)
+
+dev-цикл, snapshot/restart
+
+LangSmithBackend
+
+LANGSMITH_API_KEY
+
+через LangSmith
+
+через LS
+
+уже платите за LangSmith

examples/slide-094/script.py

@@ -0,0 +1,87 @@
+"""
+Slide 94: Slide 8
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-094/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 94 ===
+// open_swe/sandbox/__init__.py:1-12
+
+  from open_swe.sandbox import (
+      ModalBackend,
+      DaytonaBackend,
+      RunloopBackend,
+      LangSmithBackend,
+  )
+
+  # Modal (Python-first, GPU)
+  backend = ModalBackend(
+      token_id="..."
+      token_secret="..."
+  )
+
+// examples/my_internal_backend.py:1-11
+
+  # свой backend: devbox-пул
+  from open_swe.sandbox import (
+      SandboxBackend,
+  )
+>  
+  class MyInternalBackend(SandboxBackend):
+      def execute(self, cmd):
+>         return self._run(cmd)
+>  
+      def read_file(self, p):
+>         return self._fetch(p)
+
+// examples/my_internal_backend.py:1-16
+
+  # свой backend: devbox-пул
+  from open_swe.sandbox import (
+      SandboxBackend,
+  )
+
+  class MyInternalBackend(
+      SandboxBackend
+  ):
+      def __init__(self, conn):
+          self.conn = conn
+>  
+>     def execute(self, cmd):
+>         return self._run(cmd)
+>  
+>     def read_file(self, p):
+>         return self._fetch(p)
+
+// note: snippet has 16 lines, card fits ~15

examples/slide-095/script.py

@@ -0,0 +1,53 @@
+"""
+Slide 95: Slide 9
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-095/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 95 ===
+// INSTALLATION.md: step 1:1-5
+
+  # 1. prerequisites
+  python --version    # >= 3.11
+  node --version      # >= 20
+  uv --version        # или pip
+  docker --version    # для dev
+
+// INSTALLATION.md: step 2:1-5
+
+  # 2. clone + install
+  git clone https://github.com/
+      langchain-ai/open-swe.git
+  cd open-swe
+  uv sync     # или pip install -e .

examples/slide-096/script.py

@@ -0,0 +1,53 @@
+"""
+Slide 96: Slide 10
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-096/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 96 ===
+// INSTALLATION.md: steps 3-5:1-13
+
+  # 3. backend (FastAPI)
+  uv run apps/open-swe/main.py
+  # -> :8000
+
+  # 4. UI (TanStack Start + Vite)
+  cd apps/open-swe-ui
+  pnpm install && pnpm dev
+  # -> :3000
+
+  # 5. smoke-test
+  curl -X POST :8000/webhooks/slack \
+    -d '{"text":"@open-swe hello"}'
+  # -> {"thread_id": "..."}

examples/slide-097/script.py

@@ -0,0 +1,53 @@
+"""
+Slide 97: Slide 11
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-097/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 97 ===
+// config/github-app-manifest.yaml:1-13
+
+  # github-app-manifest.yaml
+  name: open-swe-internal
+> url: https://open-swe.example.com
+> hook_attributes:
+>   url: https://open-swe.example.com/
+>     webhooks/github
+>   events:
+>     - issue_comment
+>     - pull_request
+      - pull_request_review
+  default_permissions:
+    contents: write
+    pull_requests: write

examples/slide-098/script.py

@@ -0,0 +1,50 @@
+"""
+Slide 98: Slide 12
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-098/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 98 ===
+// .env:1-10
+
+  # .env (НЕ коммитить)
+  LANGSMITH_TRACING=true
+  LANGSMITH_ENDPOINT=https://
+      api.smith.langchain.com
+  LANGSMITH_API_KEY=lsv2_...
+  LANGSMITH_PROJECT=open-swe-prod
+  LANGSMITH_SNAPSHOT=true
+
+  # для sandbox-прокси:
+  LANGSMITH_SANDBOX_BACKEND=true

examples/slide-099/script.py

@@ -0,0 +1,46 @@
+"""
+Slide 99: Slide 13
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-099/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 99 ===
+@open-swe fix the auth bug
+repo:acme/api
+
+@openswe implement the
+acceptance criteria
+
+@openswe address
+the review comments

examples/slide-100/script.py

@@ -0,0 +1,51 @@
+"""
+Slide 100: Slide 14
+Section 4: Open SWE
+Source: slides/section4-openswe/section4.pptx
+
+Сгенерировано автоматически из slide-NN.js / sectionN.pptx.
+Паттерн провайдера скопирован из
+bro-js/agents/teacher/assistant/src/angry_teacher/llm.py.
+
+Запуск:
+  cd langchain-evolution-deck
+  cp .env.example .env   # заполни OPENAI_API_KEY
+  python examples/slide-100/script.py
+"""
+import os
+from dotenv import load_dotenv
+from langchain_openai import ChatOpenAI
+
+load_dotenv()
+
+llm = ChatOpenAI(
+    # model="openrouter/free",
+    # model="qwen/qwen3.5-35b-a3b",
+    model="openai/gpt-oss-20b",
+    # model="nvidia/nemotron-3-nano",
+    # model="qwen/qwen3.5-9b",
+    base_url="https://llm.brojs.ru/v1",
+    # base_url="https://api.minimax.io/v1",
+    # base_url="http://0.0.0.0:8090/v1",
+    # base_url="https://openrouter.ai/api/v1",
+    # api_key=os.getenv("MINIMAX_API_KEY"),
+    api_key=(os.getenv("OPENAI_API_KEY") or "").strip() or None,
+    temperature=0.7,
+    stream_usage=True,
+)
+
+
+# === Code from slide 100 ===
+// open_swe/triggers/router.py:1-11
+
+  # open_swe/triggers/router.py
+> def thread_id_for(source, ref, comment_id):
+>     # Deterministic thread_id:
+>     # все follow-up попадают в один run.
+>     if source == "slack":
+>         return f"slack:{ref}"
+>     if source == "linear":
+>         return f"linear:{ref}"
+>     if source == "github":
+          return f"github:{ref}:{comment_id}"
+      raise ValueError(source)