如何为聊天机器人添加工具

先决条件

本指南假设您熟悉以下概念：

本节将介绍如何创建会话式代理：能够使用工具与其他系统和 API 进行交互的聊天机器人。

note

此操作指南以前是使用 RunnableWithMessageHistory 构建聊天机器人。您可以在 v0.2 文档中找到此版本的指南。

自 LangChain v0.3 版本发布以来，我们建议 LangChain 用户利用 LangGraph 持久化将 memory 集成到新的 LangChain 应用程序中。

如果您的代码已依赖于 RunnableWithMessageHistory 或 BaseChatMessageHistory，则无需进行任何更改。我们目前不打算弃用此功能，因为它适用于简单的聊天应用程序，并且任何使用 RunnableWithMessageHistory 的代码将继续按预期工作。

有关更多详细信息，请参阅如何迁移到 LangGraph Memory。

设置

在本指南中，我们将使用一个工具调用代理，该代理只包含一个用于搜索网络的工具。默认将由 Tavily 提供支持，但您可以将其替换为任何类似的工具。本节其余部分将假定您使用的是 Tavily。

您需要访问 Tavily 网站进行注册账户，并安装以下软件包：

%pip install --upgrade --quiet langchain-openai tavily-python langgraph

import getpass
import os

if not os.environ.get("OPENAI_API_KEY"):
    os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")

if not os.environ.get("TAVILY_API_KEY"):
    os.environ["TAVILY_API_KEY"] = getpass.getpass("Tavily API Key:")

您还需要将 OpenAI 密钥设置为 OPENAI_API_KEY，并将 Tavily API 密钥设置为 TAVILY_API_KEY。

创建一个 Agent

我们的最终目标是创建一个 Agent，使其能够与用户进行对话式交互，并在需要时查找信息。

首先，让我们初始化 Tavily 和一个支持工具调用的 OpenAI chat model：

from langchain_openai import ChatOpenAI
from langchain_tavily import TavilySearch

tools = [TavilySearch(max_results=10, topic="general")]

# Choose the LLM that will drive the agent
# Only certain models support this
model = ChatOpenAI(model="gpt-4o-mini")

API Reference:ChatOpenAI

为了让我们的代理具有对话能力，我们还可以指定一个提示（prompt）。下面是一个例子：

prompt = (
    "You are a helpful assistant. "
    "You may not need to use tools for every query - the user may just want to chat!"
)

太棒了！现在，让我们使用 LangGraph 的预构建模块 create_react_agent 来组装我们的代理，该模块允许你创建一个 tool-calling agent：

from langgraph.prebuilt import create_react_agent

# prompt allows you to preprocess the inputs to the model inside ReAct agent
# in this case, since we're passing a prompt string, we'll just always add a SystemMessage
# with this prompt string before any other messages sent to the model
agent = create_react_agent(model, tools, prompt=prompt)

API Reference:create_react_agent

运行 Agent

既然我们已经设置好了 Agent，就来尝试与它交互吧！它可以处理一些无需查询的简单问题：

from langchain_core.messages import HumanMessage

agent.invoke({"messages": [HumanMessage(content="I'm Nemo!")]})

API Reference:HumanMessage

{'messages': [HumanMessage(content="I'm Nemo!", additional_kwargs={}, response_metadata={}, id='40b60204-1af1-40d4-b6a7-b845a2281dd6'),
  AIMessage(content='Hi Nemo! How can I assist you today?', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 11, 'prompt_tokens': 795, 'total_tokens': 806, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsUwqprT2mVdjqu1aaSm1jVVWYVz', 'service_tier': 'default', 'finish_reason': 'stop', 'logprobs': None}, id='run--08282ec6-6d3e-4495-b004-b3b08f3879c3-0', usage_metadata={'input_tokens': 795, 'output_tokens': 11, 'total_tokens': 806, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})]}

或者，如有需要，它可以使用传入的搜索工具来获取最新信息：

agent.invoke(
    {
        "messages": [
            HumanMessage(
                content="What is the current conservation status of the Great Barrier Reef?"
            )
        ],
    }
)

{'messages': [HumanMessage(content='What is the current conservation status of the Great Barrier Reef?', additional_kwargs={}, response_metadata={}, id='5240955c-d842-408d-af3d-4ee74db29dbd'),
  AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_W37BFkNuZlJu9US1Tl71xpiX', 'function': {'arguments': '{"query":"current conservation status of the Great Barrier Reef","time_range":"year","topic":"general"}', 'name': 'tavily_search'}, 'type': 'function'}], 'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 32, 'prompt_tokens': 804, 'total_tokens': 836, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsV6EJ7F1vDipoG4dpEiBRZvuTLo', 'service_tier': 'default', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run--5f5b32d7-fb80-4913-a7ec-ca9c5acaa101-0', tool_calls=[{'name': 'tavily_search', 'args': {'query': 'current conservation status of the Great Barrier Reef', 'time_range': 'year', 'topic': 'general'}, 'id': 'call_W37BFkNuZlJu9US1Tl71xpiX', 'type': 'tool_call'}], usage_metadata={'input_tokens': 804, 'output_tokens': 32, 'total_tokens': 836, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}}),
  ToolMessage(content='{"query": "current conservation status of the Great Barrier Reef", "follow_up_questions": null, "answer": null, "images": [], "results": [{"title": "The Great Barrier Reef: Current Conservation Efforts and Future Outlook", "url": "https://discoverwildscience.com/the-great-barrier-reef-current-conservation-efforts-and-future-outlook-1-279446/", "content": "The Great Barrier Reef, a mesmerizing marvel of nature, stretches over 2,300 kilometers along the northeast coast of Australia. As the largest coral reef system in the world, it is home to an incredible diversity of marine life, including more than 1,500 species of fish and 411 types of hard coral.", "score": 0.6353361, "raw_content": null}, {"title": "Monitoring progress - Protecting the Great Barrier Reef", "url": "https://www.detsi.qld.gov.au/great-barrier-reef/monitoring-progress", "content": "Stay informed about the current state of the Great Barrier Reef through comprehensive monitoring reports and reef report cards. Delve into the scientific research and advancements contributing to reef conservation. Learn about ongoing efforts to track progress and ensure the reef\'s long-term health.", "score": 0.6347929, "raw_content": null}, {"title": "Great Barrier Reef Outlook Report shows that the reef is in serious ...", "url": "https://biodiversitycouncil.org.au/news/great-barrier-reef-outlook-report-shows-that-the-reef-is-in-serious-trouble", "content": "The Great Barrier Reef is in very serious trouble. Climate change is the biggest threat to the reef. Catchment restoration activities that reduce sediment flowing to the reef will aid the health of the reef but cannot match the scale of destruction occurring due to marine heatwaves caused by climate change.", "score": 0.5183761, "raw_content": null}, {"title": "Water pollution threatens Great Barrier Reef\'s survival: new report ...", "url": "https://www.marineconservation.org.au/water-pollution-threatens-great-barrier-reefs-survival-new-report-highlights-funding-need/", "content": "While this investment has supported critical work across the Great Barrier Reef catchments, more funding is needed. At current rates, the target to cut fine sediment by 25% on 2009 levels will not be met until 2047, while the target to reduce dissolved inorganic nitrogen by 60% is not expected to be achieved until 2114.", "score": 0.51383984, "raw_content": null}, {"title": "What is the state of the Great Barrier Reef? - Tangaroa Blue", "url": "https://tangaroablue.org/the-state-of-the-great-barrier-reef/", "content": "The Great Barrier Reef Outlook Report 2024, prepared every five years by the Great Barrier Reef Marine Park Authority, summarises the Reef\'s long-term outlook based on its use, management, and risks.This year\'s report uses data from the Australian Marine Debris Initiative Database to analyse the risks and impacts of marine debris on the Great Barrier Reef and help identify areas for", "score": 0.47489962, "raw_content": null}, {"title": "New report on Great Barrier Reef shows coral cover increases before ...", "url": "https://www.aims.gov.au/information-centre/news-and-stories/new-report-great-barrier-reef-shows-coral-cover-increases-onset-serious-bleaching-cyclones", "content": "Coral cover has increased in all three regions on the Great Barrier Reef and is at regional highs in two of the three regions. But the results come with a note of caution. ... trained scientists during manta tow surveys and is a metric which allows AIMS scientists to provide an overview of the Great Barrier Reef\'s status and keep policy", "score": 0.40330887, "raw_content": null}, {"title": "Cycle of coral bleaching on the Great Barrier Reef now at \'catastrophic ...", "url": "https://www.sydney.edu.au/news-opinion/news/2025/01/21/coral-bleaching-2024-great-barrier-reef-one-tree-island.html", "content": "As the Great Barrier Reef faces increasing threats from climate change, the study calls for a collaborative approach to conservation that involves local communities, scientists and policymakers. Dr Shawna Foo , a Sydney Horizon Fellow and co-author of the study, said: \\"Seeing the impacts on a reef that has largely avoided mass bleaching until", "score": 0.3759361, "raw_content": null}, {"title": "Great Barrier Reef Outlook Report 2024: An ecosystem under pressure", "url": "https://icriforum.org/gbr-outlook-report-2024/", "content": "The 2024 Great Barrier Reef Outlook Report is the fourth in a series of comprehensive five-yearly reports on the Reef\'s health, pressures, management, and potential future. It found climate-driven threats such as warming oceans and severe cyclones have been compounding other impacts from crown-of-thorns starfish outbreaks, poor water quality", "score": 0.34634283, "raw_content": null}, {"title": "UNESCO expresses \'utmost concern\' at the state of the Great Barrier Reef", "url": "https://theconversation.com/unesco-expresses-utmost-concern-at-the-state-of-the-great-barrier-reef-257638", "content": "This 2017 photo from Ribbon Reef, near Cairns, shows what a healthy reef looks like. J Summerling/AP Poor water quality persists. Poor water quality is a major issue on the Great Barrier Reef.", "score": 0.31069487, "raw_content": null}, {"title": "Reef health updates | Reef Authority - gbrmpa", "url": "https://www2.gbrmpa.gov.au/learn/reef-health/reef-health-updates", "content": "As the lead managers of the Great Barrier Reef, the Reef Authority keeps an eye on the Reef year-round — with efforts stepped up over summer, a typically high-risk period from extreme weather. The Reef Authority releases updates on the health of Reef which includes; sea surface temperatures, rainfall and floods, cyclones, crown-of-thorns", "score": 0.18051112, "raw_content": null}], "response_time": 2.07}', name='tavily_search', id='cbf7ae84-1df7-4ead-b00d-f8fba2152720', tool_call_id='call_W37BFkNuZlJu9US1Tl71xpiX'),
  AIMessage(content='The current conservation status of the Great Barrier Reef is concerning. The reef is facing significant threats primarily due to climate change, which is causing marine heatwaves and coral bleaching. A report highlights that while there have been some local efforts in conservation, such as catchment restoration to reduce sediment flow, these cannot keep pace with the destruction caused by climate impacts. Recent findings from the 2024 Great Barrier Reef Outlook Report indicate that climate-driven phenomena like warming oceans and severe cyclones are exacerbating other pressures, such as crown-of-thorns starfish outbreaks and poor water quality.\n\nSome reports have indicated that coral cover has increased in certain regions of the reef, but overall, the health of the reef remains in serious decline. There’s an urgent call for more funding and collaborative efforts between local communities, scientists, and policymakers to enhance conservation measures.\n\nFor more detailed information, you can refer to these articles:\n- [The Great Barrier Reef: Current Conservation Efforts and Future Outlook](https://discoverwildscience.com/the-great-barrier-reef-current-conservation-efforts-and-future-outlook-1-279446/)\n- [Great Barrier Reef Outlook Report 2024: An ecosystem under pressure](https://icriforum.org/gbr-outlook-report-2024/)', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 255, 'prompt_tokens': 2208, 'total_tokens': 2463, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsVAxeGL7PKGVkb2DieFPE0ZPgor', 'service_tier': 'default', 'finish_reason': 'stop', 'logprobs': None}, id='run--71441b27-81a0-427f-8784-b2ea674bebd4-0', usage_metadata={'input_tokens': 2208, 'output_tokens': 255, 'total_tokens': 2463, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})]}

对话式回复

由于我们的提示中包含聊天历史消息的占位符，我们的代理还可以考虑之前的交互，并像标准聊天机器人一样以对话方式响应：

from langchain_core.messages import AIMessage, HumanMessage

agent.invoke(
    {
        "messages": [
            HumanMessage(content="I'm Nemo!"),
            AIMessage(content="Hello Nemo! How can I assist you today?"),
            HumanMessage(content="What is my name?"),
        ],
    }
)

API Reference:AIMessage | HumanMessage

{'messages': [HumanMessage(content="I'm Nemo!", additional_kwargs={}, response_metadata={}, id='8a67dea0-acd8-40f9-8c28-292c5f81c05f'),
  AIMessage(content='Hello Nemo! How can I assist you today?', additional_kwargs={}, response_metadata={}, id='92a2533e-5c62-4cbe-80f1-302f5f1caf28'),
  HumanMessage(content='What is my name?', additional_kwargs={}, response_metadata={}, id='efa8c3d3-86d7-428f-985e-a3aadd6504bc'),
  AIMessage(content='Your name is Nemo!', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 6, 'prompt_tokens': 818, 'total_tokens': 824, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsVIf5MX5jXUEjYCorT5bWYzc7iu', 'service_tier': 'default', 'finish_reason': 'stop', 'logprobs': None}, id='run--a1a32c7d-8066-4954-86f9-3a8f43fcb48d-0', usage_metadata={'input_tokens': 818, 'output_tokens': 6, 'total_tokens': 824, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})]}

如果愿意，你还可以为 LangGraph 代理添加内存来管理消息历史记录。我们将其重新声明如下：

from langgraph.checkpoint.memory import MemorySaver

memory = MemorySaver()
agent = create_react_agent(model, tools, prompt=prompt, checkpointer=memory)

API Reference:MemorySaver

agent.invoke(
    {"messages": [HumanMessage("I'm Nemo!")]},
    config={"configurable": {"thread_id": "1"}},
)

{'messages': [HumanMessage(content="I'm Nemo!", additional_kwargs={}, response_metadata={}, id='31c2249a-13eb-4040-b56d-0c8746fa158e'),
  AIMessage(content='Hello, Nemo! How can I assist you today?', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 12, 'prompt_tokens': 795, 'total_tokens': 807, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsVRB0FItvtPawTTIAjNwgmlQFFw', 'service_tier': 'default', 'finish_reason': 'stop', 'logprobs': None}, id='run--a9703ca1-de4c-4f76-b622-9683d86ca777-0', usage_metadata={'input_tokens': 795, 'output_tokens': 12, 'total_tokens': 807, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})]}

然后，如果我们重新运行我们的包装代理执行器：

agent.invoke(
    {"messages": [HumanMessage("What is my name?")]},
    config={"configurable": {"thread_id": "1"}},
)

{'messages': [HumanMessage(content="I'm Nemo!", additional_kwargs={}, response_metadata={}, id='31c2249a-13eb-4040-b56d-0c8746fa158e'),
  AIMessage(content='Hello, Nemo! How can I assist you today?', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 12, 'prompt_tokens': 795, 'total_tokens': 807, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsVRB0FItvtPawTTIAjNwgmlQFFw', 'service_tier': 'default', 'finish_reason': 'stop', 'logprobs': None}, id='run--a9703ca1-de4c-4f76-b622-9683d86ca777-0', usage_metadata={'input_tokens': 795, 'output_tokens': 12, 'total_tokens': 807, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}}),
  HumanMessage(content='What is my name?', additional_kwargs={}, response_metadata={}, id='0cde6457-8d4d-45d5-b175-ad846018c4d2'),
  AIMessage(content='Your name is Nemo! How can I help you today, Nemo?', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 15, 'prompt_tokens': 819, 'total_tokens': 834, 'completion_tokens_details': {'accepted_prediction_tokens': 0, 'audio_tokens': 0, 'reasoning_tokens': 0, 'rejected_prediction_tokens': 0}, 'prompt_tokens_details': {'audio_tokens': 0, 'cached_tokens': 0}}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_34a54ae93c', 'id': 'chatcmpl-BjsVTa1plxGPNitbOcw7YVTFdmz1e', 'service_tier': 'default', 'finish_reason': 'stop', 'logprobs': None}, id='run--1d742bc1-5839-4837-b6f4-9a6b92fa6897-0', usage_metadata={'input_tokens': 819, 'output_tokens': 15, 'total_tokens': 834, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})]}

此 LangSmith 跟踪展示了幕后发生的情况。

进一步阅读

要了解更多关于如何构建代理的信息，请参阅这些 LangGraph 指南：

要了解更多关于工具使用的问题，您还可以查看此用例部分。

设置​

创建一个 Agent​

运行 Agent​

对话式回复​

进一步阅读​

设置

创建一个 Agent

运行 Agent

对话式回复

进一步阅读