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href="/docs/how_to/callbacks_constructor/">How to propagate callbacks constructor</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/callbacks_custom_events/">How to dispatch custom callback events</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/callbacks_runtime/">How to pass callbacks in at runtime</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/character_text_splitter/">How to split by character</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/chat_model_caching/">How to cache chat model responses</a></li><li class="theme-doc-sidebar-item-link 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theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/custom_embeddings/">Custom Embeddings</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/custom_llm/">How to create a custom LLM class</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/custom_retriever/">Custom Retriever</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/custom_tools/">How to create tools</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/debugging/">How to debug your LLM apps</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/document_loader_csv/">How to load CSVs</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/document_loader_directory/">How to load documents from a directory</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/document_loader_html/">How to load HTML</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/document_loader_json/">How to load JSON</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/document_loader_markdown/">How to load 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tabindex="0" href="/docs/how_to/embed_text/">Text embedding models</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/ensemble_retriever/">How to combine results from multiple retrievers</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/example_selectors_langsmith/">How to select examples from a LangSmith dataset</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/example_selectors_length_based/">How to select examples by length</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/example_selectors_mmr/">How to select examples by maximal marginal relevance 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API</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/inspect/">How to inspect runnables</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/lcel_cheatsheet/">LangChain Expression Language Cheatsheet</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/llm_caching/">How to cache LLM responses</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/llm_token_usage_tracking/">How to track token usage for LLMs</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" 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class="menu__link" tabindex="0" href="/docs/how_to/multimodal_prompts/">How to use multimodal prompts</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/output_parser_custom/">How to create a custom Output Parser</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/output_parser_fixing/">How to use the output-fixing parser</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/output_parser_json/">How to parse JSON output</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/output_parser_retry/">How to retry when a parsing error occurs</a></li><li 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href="/docs/how_to/runnable_runtime_secrets/">How to pass runtime secrets to runnables</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/self_query/">How to do "self-querying" retrieval</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/semantic-chunker/">How to split text based on semantic similarity</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/sequence/">How to chain runnables</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/serialization/">How to save and load LangChain objects</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/split_by_token/">How to split text by tokens</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/split_html/">How to split HTML</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/sql_csv/">How to do question answering over CSVs</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/sql_large_db/">How to deal with large databases when doing SQL question-answering</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item hidden"><a class="menu__link" tabindex="0" href="/docs/how_to/sql_prompting/">How to better 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href="/docs/tutorials/"><span itemprop="name">Tutorials</span></a><meta itemprop="position" content="1"></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item breadcrumbs__item--active"><span class="breadcrumbs__link" itemprop="name">Build a Chatbot</span><meta itemprop="position" content="2"></li></ul></nav><div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type="button" class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div style="display:flex;flex-direction:column;align-items:flex-end;float:right;margin-left:12px"><a target="_blank" href="https://colab.research.google.com/github/langchain-ai/langchain/blob/master/docs/docs/tutorials/chatbot.ipynb"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab"></a><a href="https://github.com/langchain-ai/langchain/blob/master/docs/docs/tutorials/chatbot.ipynb" target="_blank"><img src="https://img.shields.io/badge/Open%20on%20GitHub-grey?logo=github&logoColor=white" alt="Open on GitHub"></a></div><div class="theme-doc-markdown markdown"><header><h1>Build a Chatbot</h1></header> <div class="theme-admonition theme-admonition-note admonition_xJq3 alert alert--secondary"><div class="admonitionHeading_Gvgb"><span class="admonitionIcon_Rf37"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg></span>note</div><div class="admonitionContent_BuS1"><p>This tutorial previously used the <a href="https://python.langchain.com/api_reference/core/runnables/langchain_core.runnables.history.RunnableWithMessageHistory.html" target="_blank" rel="noopener noreferrer">RunnableWithMessageHistory</a> abstraction. You can access that version of the documentation in the <a href="https://python.langchain.com/v0.2/docs/tutorials/chatbot/" target="_blank" rel="noopener noreferrer">v0.2 docs</a>.</p><p>As of the v0.3 release of LangChain, we recommend that LangChain users take advantage of <a href="https://langchain-ai.github.io/langgraph/concepts/persistence/" target="_blank" rel="noopener noreferrer">LangGraph persistence</a> to incorporate <code>memory</code> into new LangChain applications.</p><p>If your code is already relying on <code>RunnableWithMessageHistory</code> or <code>BaseChatMessageHistory</code>, you do <strong>not</strong> need to make any changes. We do not plan on deprecating this functionality in the near future as it works for simple chat applications and any code that uses <code>RunnableWithMessageHistory</code> will continue to work as expected.</p><p>Please see <a href="/docs/versions/migrating_memory/">How to migrate to LangGraph Memory</a> for more details.</p></div></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="overview">Overview<a href="#overview" class="hash-link" aria-label="Direct link to Overview" title="Direct link to Overview"></a></h2> <p>We'll go over an example of how to design and implement an LLM-powered chatbot. This chatbot will be able to have a conversation and remember previous interactions with a <a href="/docs/concepts/chat_models/">chat model</a>.</p> <p>Note that this chatbot that we build will only use the language model to have a conversation. There are several other related concepts that you may be looking for:</p> <ul> <li><a href="/docs/tutorials/qa_chat_history/">Conversational RAG</a>: Enable a chatbot experience over an external source of data</li> <li><a href="/docs/tutorials/agents/">Agents</a>: Build a chatbot that can take actions</li> </ul> <p>This tutorial will cover the basics which will be helpful for those two more advanced topics, but feel free to skip directly to there should you choose.</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="setup">Setup<a href="#setup" class="hash-link" aria-label="Direct link to Setup" title="Direct link to Setup"></a></h2> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="jupyter-notebook">Jupyter Notebook<a href="#jupyter-notebook" class="hash-link" aria-label="Direct link to Jupyter Notebook" title="Direct link to Jupyter Notebook"></a></h3> <p>This guide (and most of the other guides in the documentation) uses <a href="https://jupyter.org/" target="_blank" rel="noopener noreferrer">Jupyter notebooks</a> and assumes the reader is as well. Jupyter notebooks are perfect for learning how to work with LLM systems because oftentimes things can go wrong (unexpected output, API down, etc) and going through guides in an interactive environment is a great way to better understand them.</p> <p>This and other tutorials are perhaps most conveniently run in a Jupyter notebook. See <a href="https://jupyter.org/install" target="_blank" rel="noopener noreferrer">here</a> for instructions on how to install.</p> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="installation">Installation<a href="#installation" class="hash-link" aria-label="Direct link to Installation" title="Direct link to Installation"></a></h3> <p>For this tutorial we will need <code>langchain-core</code> and <code>langgraph</code>. This guide requires <code>langgraph >= 0.2.28</code>.</p> <!-- --> <div class="tabs-container tabList__CuJ"><ul role="tablist" aria-orientation="horizontal" class="tabs"><li role="tab" tabindex="0" aria-selected="true" class="tabs__item tabItem_LNqP tabs__item--active">Pip</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">Conda</li></ul><div class="margin-top--md"><div role="tabpanel" class="tabItem_Ymn6"><div class="language-bash codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-bash codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">pip install langchain-core langgraph>0.2.27</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden=""><div class="language-bash codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-bash codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">conda install langchain-core langgraph>0.2.27 -c conda-forge</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div></div></div></div> <p>For more details, see our <a href="/docs/how_to/installation/">Installation guide</a>.</p> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="langsmith">LangSmith<a href="#langsmith" class="hash-link" aria-label="Direct link to LangSmith" title="Direct link to LangSmith"></a></h3> <p>Many of the applications you build with LangChain will contain multiple steps with multiple invocations of LLM calls. As these applications get more and more complex, it becomes crucial to be able to inspect what exactly is going on inside your chain or agent. The best way to do this is with <a href="https://smith.langchain.com" target="_blank" rel="noopener noreferrer">LangSmith</a>.</p> <p>After you sign up at the link above, make sure to set your environment variables to start logging traces:</p> <div class="language-shell codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-shell codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">export LANGSMITH_TRACING="true"</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">export LANGSMITH_API_KEY="..."</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Or, if in a notebook, you can set them with:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> getpass</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> os</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">os</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">environ</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"LANGSMITH_TRACING"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"true"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">os</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">environ</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"LANGSMITH_API_KEY"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> getpass</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">getpass</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="quickstart">Quickstart<a href="#quickstart" class="hash-link" aria-label="Direct link to Quickstart" title="Direct link to Quickstart"></a></h2> <p>First up, let's learn how to use a language model by itself. LangChain supports many different language models that you can use interchangeably - select the one you want to use below!</p> <!-- --> <div><div style="display:flex;align-items:center;margin-bottom:1rem;gap:0.75rem"><span style="font-size:1rem;font-weight:500">Select <a href="/docs/integrations/chat/">chat model</a>:</span><div class="dropdown"><button class="button button--secondary" style="background-color:var(--ifm-background-color);border:1px solid var(--ifm-color-emphasis-300);font-weight:normal;font-size:1rem;padding:0.5rem 1rem;color:var(--ifm-font-color-base)">Groq<span style="margin-left:0.4rem;font-size:0.875rem">▾</span></button><div class="dropdown__menu" style="max-height:210px;overflow-y:auto;overflow-x:hidden;margin-bottom:0"><li><a class="dropdown__link dropdown__link--active" href="#">Groq</a></li><li><a class="dropdown__link" href="#">OpenAI</a></li><li><a class="dropdown__link" href="#">Anthropic</a></li><li><a class="dropdown__link" href="#">Azure</a></li><li><a class="dropdown__link" href="#">Google Vertex</a></li><li><a class="dropdown__link" href="#">AWS</a></li><li><a class="dropdown__link" href="#">Cohere</a></li><li><a class="dropdown__link" href="#">NVIDIA</a></li><li><a class="dropdown__link" href="#">Fireworks AI</a></li><li><a class="dropdown__link" href="#">Mistral AI</a></li><li><a class="dropdown__link" href="#">Together AI</a></li><li><a class="dropdown__link" href="#">IBM watsonx</a></li><li><a class="dropdown__link" href="#">Databricks</a></li></div></div></div><div class="language-bash codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-bash codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">pip install -qU "langchain[groq]"</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> getpass</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> os</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">if</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">not</span><span class="token plain"> os</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">environ</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">get</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"GROQ_API_KEY"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> os</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">environ</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"GROQ_API_KEY"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> getpass</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">getpass</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Enter API key for Groq: "</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langchain</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">chat_models </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> init_chat_model</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">model </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> init_chat_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"llama3-8b-8192"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> model_provider</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"groq"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div></div> <p>Let's first use the model directly. <code>ChatModel</code>s are instances of LangChain "Runnables", which means they expose a standard interface for interacting with them. To just simply call the model, we can pass in a list of messages to the <code>.invoke</code> method.</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langchain_core</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">messages </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> HumanMessage</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"Hi! I'm Bob"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div style="padding-top:1.3rem;background:var(--prism-background-color);color:var(--prism-color);margin-top:calc(-1 * var(--ifm-leading) - 5px);margin-bottom:var(--ifm-leading);box-shadow:var(--ifm-global-shadow-lw);border-bottom-left-radius:var(--ifm-code-border-radius);border-bottom-right-radius:var(--ifm-code-border-radius)"><b style="padding-left:0.65rem;margin-bottom:0.45rem;margin-right:0.5rem">API Reference:</b><span><a href="https://python.langchain.com/api_reference/core/messages/langchain_core.messages.human.HumanMessage.html">HumanMessage</a></span></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">AIMessage(content='Hi Bob! How can I assist you today?', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 10, 'prompt_tokens': 11, 'total_tokens': 21, '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_0705bf87c0', 'finish_reason': 'stop', 'logprobs': None}, id='run-5211544f-da9f-4325-8b8e-b3d92b2fc71a-0', usage_metadata={'input_tokens': 11, 'output_tokens': 10, 'total_tokens': 21, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>The model on its own does not have any concept of state. For example, if you ask a followup question:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"What's my name?"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">AIMessage(content="I'm sorry, but I don't have access to personal information about users unless it has been shared with me in the course of our conversation. How can I assist you today?", additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 34, 'prompt_tokens': 11, 'total_tokens': 45, '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_0705bf87c0', 'finish_reason': 'stop', 'logprobs': None}, id='run-a2d13a18-7022-4784-b54f-f85c097d1075-0', usage_metadata={'input_tokens': 11, 'output_tokens': 34, 'total_tokens': 45, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Let's take a look at the example <a href="https://smith.langchain.com/public/5c21cb92-2814-4119-bae9-d02b8db577ac/r" target="_blank" rel="noopener noreferrer">LangSmith trace</a></p> <p>We can see that it doesn't take the previous conversation turn into context, and cannot answer the question. This makes for a terrible chatbot experience!</p> <p>To get around this, we need to pass the entire <a href="/docs/concepts/chat_history/">conversation history</a> into the model. Let's see what happens when we do that:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langchain_core</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">messages </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> AIMessage</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"Hi! I'm Bob"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"Hello Bob! How can I assist you today?"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"What's my name?"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div style="padding-top:1.3rem;background:var(--prism-background-color);color:var(--prism-color);margin-top:calc(-1 * var(--ifm-leading) - 5px);margin-bottom:var(--ifm-leading);box-shadow:var(--ifm-global-shadow-lw);border-bottom-left-radius:var(--ifm-code-border-radius);border-bottom-right-radius:var(--ifm-code-border-radius)"><b style="padding-left:0.65rem;margin-bottom:0.45rem;margin-right:0.5rem">API Reference:</b><span><a href="https://python.langchain.com/api_reference/core/messages/langchain_core.messages.ai.AIMessage.html">AIMessage</a></span></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">AIMessage(content='Your name is Bob! How can I help you today, Bob?', additional_kwargs={'refusal': None}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 33, 'total_tokens': 47, '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_0705bf87c0', 'finish_reason': 'stop', 'logprobs': None}, id='run-34bcccb3-446e-42f2-b1de-52c09936c02c-0', usage_metadata={'input_tokens': 33, 'output_tokens': 14, 'total_tokens': 47, 'input_token_details': {'audio': 0, 'cache_read': 0}, 'output_token_details': {'audio': 0, 'reasoning': 0}})</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>And now we can see that we get a good response!</p> <p>This is the basic idea underpinning a chatbot's ability to interact conversationally. So how do we best implement this?</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="message-persistence">Message persistence<a href="#message-persistence" class="hash-link" aria-label="Direct link to Message persistence" title="Direct link to Message persistence"></a></h2> <p><a href="https://langchain-ai.github.io/langgraph/" target="_blank" rel="noopener noreferrer">LangGraph</a> implements a built-in persistence layer, making it ideal for chat applications that support multiple conversational turns.</p> <p>Wrapping our chat model in a minimal LangGraph application allows us to automatically persist the message history, simplifying the development of multi-turn applications.</p> <p>LangGraph comes with a simple in-memory checkpointer, which we use below. See its <a href="https://langchain-ai.github.io/langgraph/concepts/persistence/" target="_blank" rel="noopener noreferrer">documentation</a> for more detail, including how to use different persistence backends (e.g., SQLite or Postgres).</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langgraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">checkpoint</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">memory </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> MemorySaver</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langgraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">graph </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> START</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> StateGraph</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Define a new graph</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StateGraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Define the function that calls the model</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> response </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">return</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> response</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Define the (single) node in the graph</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_edge</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">START</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_node</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Add memory</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">memory </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> MemorySaver</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">app </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token builtin" style="color:rgb(0, 112, 193)">compile</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">checkpointer</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">memory</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div style="padding-top:1.3rem;background:var(--prism-background-color);color:var(--prism-color);margin-top:calc(-1 * var(--ifm-leading) - 5px);margin-bottom:var(--ifm-leading);box-shadow:var(--ifm-global-shadow-lw);border-bottom-left-radius:var(--ifm-code-border-radius);border-bottom-right-radius:var(--ifm-code-border-radius)"><b style="padding-left:0.65rem;margin-bottom:0.45rem;margin-right:0.5rem">API Reference:</b><span><a href="https://langchain-ai.github.io/langgraph/reference/checkpoints/#langgraph.checkpoint.memory.MemorySaver">MemorySaver</a> | </span><span><a href="https://langchain-ai.github.io/langgraph/reference/graphs/#langgraph.graph.state.StateGraph">StateGraph</a></span></div> <p>We now need to create a <code>config</code> that we pass into the runnable every time. This config contains information that is not part of the input directly, but is still useful. In this case, we want to include a <code>thread_id</code>. This should look like:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc123"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>This enables us to support multiple conversation threads with a single application, a common requirement when your application has multiple users.</p> <p>We can then invoke the application:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"Hi! I'm Bob."</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"> </span><span class="token comment" style="color:rgb(0, 128, 0)"># output contains all messages in state</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Hi Bob! How can I assist you today?</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"What's my name?"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Your name is Bob! How can I help you today, Bob?</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Great! Our chatbot now remembers things about us. If we change the config to reference a different <code>thread_id</code>, we can see that it starts the conversation fresh.</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc234"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">I'm sorry, but I don't have access to personal information about you unless you've shared it in this conversation. How can I assist you today?</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>However, we can always go back to the original conversation (since we are persisting it in a database)</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc123"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Your name is Bob. What would you like to discuss today?</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>This is how we can support a chatbot having conversations with many users!</p> <div class="theme-admonition theme-admonition-tip admonition_xJq3 alert alert--success"><div class="admonitionHeading_Gvgb"><span class="admonitionIcon_Rf37"><svg viewBox="0 0 12 16"><path fill-rule="evenodd" d="M6.5 0C3.48 0 1 2.19 1 5c0 .92.55 2.25 1 3 1.34 2.25 1.78 2.78 2 4v1h5v-1c.22-1.22.66-1.75 2-4 .45-.75 1-2.08 1-3 0-2.81-2.48-5-5.5-5zm3.64 7.48c-.25.44-.47.8-.67 1.11-.86 1.41-1.25 2.06-1.45 3.23-.02.05-.02.11-.02.17H5c0-.06 0-.13-.02-.17-.2-1.17-.59-1.83-1.45-3.23-.2-.31-.42-.67-.67-1.11C2.44 6.78 2 5.65 2 5c0-2.2 2.02-4 4.5-4 1.22 0 2.36.42 3.22 1.19C10.55 2.94 11 3.94 11 5c0 .66-.44 1.78-.86 2.48zM4 14h5c-.23 1.14-1.3 2-2.5 2s-2.27-.86-2.5-2z"></path></svg></span>tip</div><div class="admonitionContent_BuS1"><p>For async support, update the <code>call_model</code> node to be an async function and use <code>.ainvoke</code> when invoking the application:</p><div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token comment" style="color:rgb(0, 128, 0)"># Async function for node:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">async</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> response </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">await</span><span class="token plain"> model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">ainvoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">return</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> response</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Define graph as before:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StateGraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_edge</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">START</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_node</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">app </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token builtin" style="color:rgb(0, 112, 193)">compile</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">checkpointer</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">MemorySaver</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Async invocation:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">await</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">ainvoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div></div></div> <p>Right now, all we've done is add a simple persistence layer around the model. We can start to make the chatbot more complicated and personalized by adding in a prompt template.</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="prompt-templates">Prompt templates<a href="#prompt-templates" class="hash-link" aria-label="Direct link to Prompt templates" title="Direct link to Prompt templates"></a></h2> <p><a href="/docs/concepts/prompt_templates/">Prompt Templates</a> help to turn raw user information into a format that the LLM can work with. In this case, the raw user input is just a message, which we are passing to the LLM. Let's now make that a bit more complicated. First, let's add in a system message with some custom instructions (but still taking messages as input). Next, we'll add in more input besides just the messages.</p> <p>To add in a system message, we will create a <code>ChatPromptTemplate</code>. We will utilize <code>MessagesPlaceholder</code> to pass all the messages in.</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langchain_core</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">prompts </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> ChatPromptTemplate</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> MessagesPlaceholder</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">prompt_template </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> ChatPromptTemplate</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"system"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"You talk like a pirate. Answer all questions to the best of your ability."</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> MessagesPlaceholder</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">variable_name</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div style="padding-top:1.3rem;background:var(--prism-background-color);color:var(--prism-color);margin-top:calc(-1 * var(--ifm-leading) - 5px);margin-bottom:var(--ifm-leading);box-shadow:var(--ifm-global-shadow-lw);border-bottom-left-radius:var(--ifm-code-border-radius);border-bottom-right-radius:var(--ifm-code-border-radius)"><b style="padding-left:0.65rem;margin-bottom:0.45rem;margin-right:0.5rem">API Reference:</b><span><a href="https://python.langchain.com/api_reference/core/prompts/langchain_core.prompts.chat.ChatPromptTemplate.html">ChatPromptTemplate</a> | </span><span><a href="https://python.langchain.com/api_reference/core/prompts/langchain_core.prompts.chat.MessagesPlaceholder.html">MessagesPlaceholder</a></span></div> <p>We can now update our application to incorporate this template:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">workflow </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StateGraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> MessagesState</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> prompt </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> prompt_template</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> response </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">prompt</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">return</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> response</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_edge</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">START</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_node</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">memory </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> MemorySaver</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">app </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token builtin" style="color:rgb(0, 112, 193)">compile</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">checkpointer</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">memory</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>We invoke the application in the same way:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc345"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"Hi! I'm Jim."</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Ahoy there, Jim! What brings ye to these waters today? Be ye seekin' treasure, knowledge, or perhaps a good tale from the high seas? Arrr!</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"What is my name?"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Ye be called Jim, matey! A fine name fer a swashbuckler such as yerself! What else can I do fer ye? Arrr!</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Awesome! Let's now make our prompt a little bit more complicated. Let's assume that the prompt template now looks something like this:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">prompt_template </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> ChatPromptTemplate</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"system"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"You are a helpful assistant. Answer all questions to the best of your ability in {language}."</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> MessagesPlaceholder</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">variable_name</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Note that we have added a new <code>language</code> input to the prompt. Our application now has two parameters-- the input <code>messages</code> and <code>language</code>. We should update our application's state to reflect this:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> typing </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> Sequence</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langchain_core</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">messages </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> BaseMessage</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langgraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">graph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">message </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> add_messages</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> typing_extensions </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> Annotated</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> TypedDict</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">class</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">State</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">TypedDict</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> Annotated</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">Sequence</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">BaseMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> add_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> language</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">str</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StateGraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">State</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> State</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> prompt </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> prompt_template</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> response </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">prompt</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">return</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">response</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_edge</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">START</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_node</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">memory </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> MemorySaver</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">app </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token builtin" style="color:rgb(0, 112, 193)">compile</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">checkpointer</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">memory</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div style="padding-top:1.3rem;background:var(--prism-background-color);color:var(--prism-color);margin-top:calc(-1 * var(--ifm-leading) - 5px);margin-bottom:var(--ifm-leading);box-shadow:var(--ifm-global-shadow-lw);border-bottom-left-radius:var(--ifm-code-border-radius);border-bottom-right-radius:var(--ifm-code-border-radius)"><b style="padding-left:0.65rem;margin-bottom:0.45rem;margin-right:0.5rem">API Reference:</b><span><a href="https://python.langchain.com/api_reference/core/messages/langchain_core.messages.base.BaseMessage.html">BaseMessage</a> | </span><span><a href="https://langchain-ai.github.io/langgraph/reference/graphs/#langgraph.graph.message.add_messages">add_messages</a></span></div> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc456"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"Hi! I'm Bob."</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">language </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"Spanish"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"language"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> language</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">¡Hola, Bob! ¿Cómo puedo ayudarte hoy?</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Note that the entire state is persisted, so we can omit parameters like <code>language</code> if no changes are desired:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"What is my name?"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Tu nombre es Bob. ¿Hay algo más en lo que pueda ayudarte?</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>To help you understand what's happening internally, check out <a href="https://smith.langchain.com/public/15bd8589-005c-4812-b9b9-23e74ba4c3c6/r" target="_blank" rel="noopener noreferrer">this LangSmith trace</a>.</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="managing-conversation-history">Managing Conversation History<a href="#managing-conversation-history" class="hash-link" aria-label="Direct link to Managing Conversation History" title="Direct link to Managing Conversation History"></a></h2> <p>One important concept to understand when building chatbots is how to manage conversation history. If left unmanaged, the list of messages will grow unbounded and potentially overflow the context window of the LLM. Therefore, it is important to add a step that limits the size of the messages you are passing in.</p> <p><strong>Importantly, you will want to do this BEFORE the prompt template but AFTER you load previous messages from Message History.</strong></p> <p>We can do this by adding a simple step in front of the prompt that modifies the <code>messages</code> key appropriately, and then wrap that new chain in the Message History class.</p> <p>LangChain comes with a few built-in helpers for <a href="/docs/how_to/#messages">managing a list of messages</a>. In this case we'll use the <a href="/docs/how_to/trim_messages/">trim_messages</a> helper to reduce how many messages we're sending to the model. The trimmer allows us to specify how many tokens we want to keep, along with other parameters like if we want to always keep the system message and whether to allow partial messages:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token keyword" style="color:rgb(0, 0, 255)">from</span><span class="token plain"> langchain_core</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">messages </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> SystemMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> trim_messages</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">trimmer </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> trim_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> max_tokens</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token number" style="color:rgb(9, 134, 88)">65</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> strategy</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"last"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> token_counter</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> include_system</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token boolean">True</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> allow_partial</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token boolean">False</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> start_on</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"human"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> SystemMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"you're a good assistant"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"hi! I'm bob"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"hi!"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"I like vanilla ice cream"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"nice"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"whats 2 + 2"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"4"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"thanks"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"no problem!"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"having fun?"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">content</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"yes!"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">trimmer</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div><div style="padding-top:1.3rem;background:var(--prism-background-color);color:var(--prism-color);margin-top:calc(-1 * var(--ifm-leading) - 5px);margin-bottom:var(--ifm-leading);box-shadow:var(--ifm-global-shadow-lw);border-bottom-left-radius:var(--ifm-code-border-radius);border-bottom-right-radius:var(--ifm-code-border-radius)"><b style="padding-left:0.65rem;margin-bottom:0.45rem;margin-right:0.5rem">API Reference:</b><span><a href="https://python.langchain.com/api_reference/core/messages/langchain_core.messages.system.SystemMessage.html">SystemMessage</a> | </span><span><a href="https://python.langchain.com/api_reference/core/messages/langchain_core.messages.utils.trim_messages.html">trim_messages</a></span></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">[SystemMessage(content="you're a good assistant", additional_kwargs={}, response_metadata={}),</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage(content='whats 2 + 2', additional_kwargs={}, response_metadata={}),</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage(content='4', additional_kwargs={}, response_metadata={}),</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage(content='thanks', additional_kwargs={}, response_metadata={}),</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage(content='no problem!', additional_kwargs={}, response_metadata={}),</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> HumanMessage(content='having fun?', additional_kwargs={}, response_metadata={}),</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> AIMessage(content='yes!', additional_kwargs={}, response_metadata={})]</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>To use it in our chain, we just need to run the trimmer before we pass the <code>messages</code> input to our prompt.</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">workflow </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StateGraph</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">State</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> State</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> trimmed_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> trimmer</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> prompt </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> prompt_template</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> trimmed_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"language"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> state</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"language"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> response </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">prompt</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">return</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">response</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_edge</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">START</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">add_node</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"model"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> call_model</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">memory </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> MemorySaver</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">app </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> workflow</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token builtin" style="color:rgb(0, 112, 193)">compile</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">checkpointer</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">memory</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>Now if we try asking the model our name, it won't know it since we trimmed that part of the chat history:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc567"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"What is my name?"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">language </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"English"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> messages </span><span class="token operator" style="color:rgb(0, 0, 0)">+</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"language"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> language</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">I don't know your name. You haven't told me yet!</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>But if we ask about information that is within the last few messages, it remembers:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc678"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"What math problem did I ask?"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">language </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"English"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> messages </span><span class="token operator" style="color:rgb(0, 0, 0)">+</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">invoke</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"language"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> language</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">output</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token number" style="color:rgb(9, 134, 88)">1</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">pretty_print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">==================================[1m Ai Message [0m==================================</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">You asked what 2 + 2 equals.</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>If you take a look at LangSmith, you can see exactly what is happening under the hood in the <a href="https://smith.langchain.com/public/04402eaa-29e6-4bb1-aa91-885b730b6c21/r" target="_blank" rel="noopener noreferrer">LangSmith trace</a>.</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="streaming">Streaming<a href="#streaming" class="hash-link" aria-label="Direct link to Streaming" title="Direct link to Streaming"></a></h2> <p>Now we've got a functioning chatbot. However, one <em>really</em> important UX consideration for chatbot applications is streaming. LLMs can sometimes take a while to respond, and so in order to improve the user experience one thing that most applications do is stream back each token as it is generated. This allows the user to see progress.</p> <p>It's actually super easy to do this!</p> <p>By default, <code>.stream</code> in our LangGraph application streams application steps-- in this case, the single step of the model response. Setting <code>stream_mode="messages"</code> allows us to stream output tokens instead:</p> <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-python codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">config </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"configurable"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"thread_id"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"abc789"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">query </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"Hi I'm Todd, please tell me a joke."</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">language </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"English"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">input_messages </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">HumanMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">query</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"></span><span class="token keyword" style="color:rgb(0, 0, 255)">for</span><span class="token plain"> chunk</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> metadata </span><span class="token keyword" style="color:rgb(0, 0, 255)">in</span><span class="token plain"> app</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">stream</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> input_messages</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> </span><span class="token string" style="color:rgb(163, 21, 21)">"language"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> language</span><span class="token punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> config</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line theme-code-block-highlighted-line" style="color:#000000"><span class="token plain"> stream_mode</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"messages"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"></span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">if</span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">isinstance</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">chunk</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> AIMessage</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token comment" style="color:rgb(0, 128, 0)"># Filter to just model responses</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">chunk</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">content</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> end</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"|"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <div class="language-output codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#000000;--prism-background-color:#F5F5F5"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-output codeBlock_bY9V thin-scrollbar" style="color:#000000;background-color:#F5F5F5"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#000000"><span class="token plain">|Hi| Todd|!| Here|’s| a| joke| for| you|:</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">|Why| don|’t| skeleton|s| fight| each| other|?</span><br></span><span class="token-line" style="color:#000000"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">|Because| they| don|’t| have| the| guts|!||</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="next-steps">Next Steps<a href="#next-steps" class="hash-link" aria-label="Direct link to Next Steps" title="Direct link to Next Steps"></a></h2> <p>Now that you understand the basics of how to create a chatbot in LangChain, some more advanced tutorials you may be interested in are:</p> <ul> <li><a href="/docs/tutorials/qa_chat_history/">Conversational RAG</a>: Enable a chatbot experience over an external source of data</li> <li><a href="/docs/tutorials/agents/">Agents</a>: Build a chatbot that can take actions</li> </ul> <p>If you want to dive deeper on specifics, some things worth checking out are:</p> <ul> <li><a href="/docs/how_to/streaming/">Streaming</a>: streaming is <em>crucial</em> for chat applications</li> <li><a href="/docs/how_to/message_history/">How to add message history</a>: for a deeper dive into all things related to message history</li> <li><a href="/docs/how_to/trim_messages/">How to manage large message history</a>: more techniques for managing a large chat history</li> <li><a href="https://langchain-ai.github.io/langgraph/" target="_blank" rel="noopener noreferrer">LangGraph main docs</a>: for more detail on building with LangGraph</li> </ul></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="row margin-top--sm theme-doc-footer-edit-meta-row"><div class="col"><a href="https://github.com/langchain-ai/langchain/edit/master/docs/docs/tutorials/chatbot.ipynb" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_Z9Sw" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_JAkA"></div></div></footer></article><div style="display:flex;flex-direction:column"><hr><h4>Was this page helpful?</h4><div style="display:flex;gap:5px"><div style="display:flex;align-items:center;padding-top:10px;padding-bottom:10px;padding-left:22px;padding-right:22px;border:1px solid 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