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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_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 menu__link--active" aria-current="page" 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 Markdown</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_office_file/">How to load Microsoft Office files</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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href="/docs/how_to/example_selectors_similarity/">How to select examples by 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/extraction_examples/">How to use reference examples when doing extraction</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/extraction_long_text/">How to handle long text when doing extraction</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/extraction_parse/">How to use prompting alone (no tool calling) to do extraction</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/fallbacks/">How to add fallbacks to a runnable</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/filter_messages/">How to filter messages</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/hybrid/">Hybrid Search</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/indexing/">How to use the LangChain indexing 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" href="/docs/how_to/local_llms/">Run models locally</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/logprobs/">How to get log probabilities</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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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 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_string/">How to parse text from message 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" 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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/how_to/custom_tools.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/how_to/custom_tools.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>How to create tools</h1></header> <p>When constructing an <a href="/docs/concepts/agents/">agent</a>, you will need to provide it with a list of <a href="/docs/concepts/tools/">Tools</a> that it can use. Besides the actual function that is called, the Tool consists of several components:</p> <table><thead><tr><th>Attribute</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td>name</td><td>str</td><td>Must be unique within a set of tools provided to an LLM or agent.</td></tr><tr><td>description</td><td>str</td><td>Describes what the tool does. Used as context by the LLM or agent.</td></tr><tr><td>args_schema</td><td>pydantic.BaseModel</td><td>Optional but recommended, and required if using callback handlers. It can be used to provide more information (e.g., few-shot examples) or validation for expected parameters.</td></tr><tr><td>return_direct</td><td>boolean</td><td>Only relevant for agents. When True, after invoking the given tool, the agent will stop and return the result direcly to the user.</td></tr></tbody></table> <p>LangChain supports the creation of tools from:</p> <ol> <li>Functions;</li> <li>LangChain <a href="/docs/concepts/runnables/">Runnables</a>;</li> <li>By sub-classing from <a href="https://python.langchain.com/api_reference/core/tools/langchain_core.tools.base.BaseTool.html" target="_blank" rel="noopener noreferrer">BaseTool</a> -- This is the most flexible method, it provides the largest degree of control, at the expense of more effort and code.</li> </ol> <p>Creating tools from functions may be sufficient for most use cases, and can be done via a simple <a href="https://python.langchain.com/api_reference/core/tools/langchain_core.tools.convert.tool.html" target="_blank" rel="noopener noreferrer">@tool decorator</a>. If more configuration is needed-- e.g., specification of both sync and async implementations-- one can also use the <a href="https://python.langchain.com/api_reference/core/tools/langchain_core.tools.structured.StructuredTool.html#langchain_core.tools.structured.StructuredTool.from_function" target="_blank" rel="noopener noreferrer">StructuredTool.from_function</a> class method.</p> <p>In this guide we provide an overview of these methods.</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>Models will perform better if the tools have well chosen names, descriptions and JSON schemas.</p></div></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="creating-tools-from-functions">Creating tools from functions<a href="#creating-tools-from-functions" class="hash-link" aria-label="Direct link to Creating tools from functions" title="Direct link to Creating tools from functions"></a></h2> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="tool-decorator">@tool decorator<a href="#tool-decorator" class="hash-link" aria-label="Direct link to @tool decorator" title="Direct link to @tool decorator"></a></h3> <p>This <code>@tool</code> decorator is the simplest way to define a custom tool. The decorator uses the function name as the tool name by default, but this can be overridden by passing a string as the first argument. Additionally, the decorator will use the function's docstring as the tool's description - so a docstring MUST be provided.</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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> tool</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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)"># Let's inspect some of the attributes associated with the tool.</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">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">name</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">description</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args</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/tools/langchain_core.tools.convert.tool.html">tool</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">multiply</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Multiply two numbers.</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">{'a': {'title': 'A', 'type': 'integer'}, 'b': {'title': 'B', 'type': 'integer'}}</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 create an <strong>async</strong> implementation, 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 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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> tool</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</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)">amultiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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/tools/langchain_core.tools.convert.tool.html">tool</a></span></div> <p>Note that <code>@tool</code> supports parsing of annotations, nested schemas, and other features:</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"> Annotated</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> List</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</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)">multiply_by_max</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"> a</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 builtin" style="color:rgb(0, 112, 193)">int</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)">"scale factor"</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"> b</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">List</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 string" style="color:rgb(163, 21, 21)">"list of ints over which to take maximum"</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><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply a by the maximum of b."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">max</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">b</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply_by_max</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args_schema</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">model_json_schema</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">{'description': 'Multiply a by the maximum of b.',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'properties': {'a': {'description': 'scale factor',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'title': 'A',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'type': 'string'},</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'b': {'description': 'list of ints over which to take maximum',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'items': {'type': 'integer'},</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'title': 'B',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'type': 'array'}},</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'required': ['a', 'b'],</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'title': 'multiply_by_maxSchema',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'type': 'object'}</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>You can also customize the tool name and JSON args by passing them into the tool decorator.</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"> pydantic </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> BaseModel</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> Field</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)">class</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">CalculatorInput</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">BaseModel</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"> a</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)">int</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> Field</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"first number"</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"> b</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)">int</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> Field</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"second number"</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"multiplication-tool"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> args_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">CalculatorInput</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> return_direct</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"></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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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)"># Let's inspect some of the attributes associated with the tool.</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">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">name</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">description</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">return_direct</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">multiplication-tool</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Multiply two numbers.</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">{'a': {'description': 'first number', 'title': 'A', 'type': 'integer'}, 'b': {'description': 'second number', 'title': 'B', 'type': 'integer'}}</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">True</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> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="docstring-parsing">Docstring parsing<a href="#docstring-parsing" class="hash-link" aria-label="Direct link to Docstring parsing" title="Direct link to Docstring parsing"></a></h4> <p><code>@tool</code> can optionally parse <a href="https://google.github.io/styleguide/pyguide.html#383-functions-and-methods" target="_blank" rel="noopener noreferrer">Google Style docstrings</a> and associate the docstring components (such as arg descriptions) to the relevant parts of the tool schema. To toggle this behavior, specify <code>parse_docstring</code>:</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">parse_docstring</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"></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)">foo</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">bar</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 punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> baz</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">str</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""The foo.</span><br></span><span class="token-line" style="color:#000000"><span class="token triple-quoted-string string" style="display:inline-block;color:rgb(163, 21, 21)"></span><br></span><span class="token-line" style="color:#000000"><span class="token triple-quoted-string string" style="color:rgb(163, 21, 21)"> Args:</span><br></span><span class="token-line" style="color:#000000"><span class="token triple-quoted-string string" style="color:rgb(163, 21, 21)"> bar: The bar.</span><br></span><span class="token-line" style="color:#000000"><span class="token triple-quoted-string string" style="color:rgb(163, 21, 21)"> baz: The baz.</span><br></span><span class="token-line" style="color:#000000"><span class="token triple-quoted-string string" style="color:rgb(163, 21, 21)"> """</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"> bar</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">foo</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args_schema</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">model_json_schema</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">{'description': 'The foo.',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'properties': {'bar': {'description': 'The bar.',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'title': 'Bar',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'type': 'string'},</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'baz': {'description': 'The baz.', 'title': 'Baz', 'type': 'integer'}},</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'required': ['bar', 'baz'],</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'title': 'fooSchema',</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> 'type': 'object'}</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="theme-admonition theme-admonition-caution admonition_xJq3 alert alert--warning"><div class="admonitionHeading_Gvgb"><span class="admonitionIcon_Rf37"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg></span>caution</div><div class="admonitionContent_BuS1"><p>By default, <code>@tool(parse_docstring=True)</code> will raise <code>ValueError</code> if the docstring does not parse correctly. See <a href="https://python.langchain.com/api_reference/core/tools/langchain_core.tools.convert.tool.html" target="_blank" rel="noopener noreferrer">API Reference</a> for detail and examples.</p></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="structuredtool">StructuredTool<a href="#structuredtool" class="hash-link" aria-label="Direct link to StructuredTool" title="Direct link to StructuredTool"></a></h3> <p>The <code>StructuredTool.from_function</code> class method provides a bit more configurability than the <code>@tool</code> decorator, without requiring much additional code.</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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> StructuredTool</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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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)">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)">amultiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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">calculator </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> coroutine</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">amultiply</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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"></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 keyword" style="color:rgb(0, 0, 255)">await</span><span class="token plain"> calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</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/tools/langchain_core.tools.structured.StructuredTool.html">StructuredTool</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">6</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">10</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 configure it:</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)">class</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">CalculatorInput</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">BaseModel</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"> a</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)">int</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> Field</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"first number"</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"> b</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)">int</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> Field</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"second number"</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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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">calculator </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</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"> func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">multiply</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"> name</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"Calculator"</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"> description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"multiply numbers"</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"> args_schema</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">CalculatorInput</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"> return_direct</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"> </span><span class="token comment" style="color:rgb(0, 128, 0)"># coroutine= ... <- you can specify an async method if desired as well</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"></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">calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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"></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">calculator</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">name</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">calculator</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">description</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">calculator</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args</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">6</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">Calculator</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">multiply numbers</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">{'a': {'description': 'first number', 'title': 'A', 'type': 'integer'}, 'b': {'description': 'second number', 'title': 'B', 'type': 'integer'}}</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="creating-tools-from-runnables">Creating tools from Runnables<a href="#creating-tools-from-runnables" class="hash-link" aria-label="Direct link to Creating tools from Runnables" title="Direct link to Creating tools from Runnables"></a></h2> <p>LangChain <a href="/docs/concepts/runnables/">Runnables</a> that accept string or <code>dict</code> input can be converted to tools using the <a href="https://python.langchain.com/api_reference/core/runnables/langchain_core.runnables.base.Runnable.html#langchain_core.runnables.base.Runnable.as_tool" target="_blank" rel="noopener noreferrer">as_tool</a> method, which allows for the specification of names, descriptions, and additional schema information for arguments.</p> <p>Example usage:</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">language_models </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> GenericFakeChatModel</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">output_parsers </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> StrOutputParser</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">prompts </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> ChatPromptTemplate</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 </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 punctuation" style="color:rgb(4, 81, 165)">(</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><span class="token string" style="color:rgb(163, 21, 21)">"Hello. Please respond in the style of {answer_style}."</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"></span><span class="token comment" style="color:rgb(0, 128, 0)"># Placeholder LLM</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain">llm </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> GenericFakeChatModel</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">messages</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token builtin" style="color:rgb(0, 112, 193)">iter</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)">"hello matey"</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">chain </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> prompt </span><span class="token operator" style="color:rgb(0, 0, 0)">|</span><span class="token plain"> llm </span><span class="token operator" style="color:rgb(0, 0, 0)">|</span><span class="token plain"> StrOutputParser</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">as_tool </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> chain</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">as_tool</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"> name</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"Style responder"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"Description of when to use tool."</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">as_tool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args</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/language_models/langchain_core.language_models.fake_chat_models.GenericFakeChatModel.html">GenericFakeChatModel</a> | </span><span><a href="https://python.langchain.com/api_reference/core/output_parsers/langchain_core.output_parsers.string.StrOutputParser.html">StrOutputParser</a> | </span><span><a href="https://python.langchain.com/api_reference/core/prompts/langchain_core.prompts.chat.ChatPromptTemplate.html">ChatPromptTemplate</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">/var/folders/4j/2rz3865x6qg07tx43146py8h0000gn/T/ipykernel_95770/2548361071.py:14: LangChainBetaWarning: This API is in beta and may change in the future.</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> as_tool = chain.as_tool(</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">{'answer_style': {'title': 'Answer Style', 'type': 'string'}}</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>See <a href="/docs/how_to/convert_runnable_to_tool/">this guide</a> for more detail.</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="subclass-basetool">Subclass BaseTool<a href="#subclass-basetool" class="hash-link" aria-label="Direct link to Subclass BaseTool" title="Direct link to Subclass BaseTool"></a></h2> <p>You can define a custom tool by sub-classing from <code>BaseTool</code>. This provides maximal control over the tool definition, but requires writing more code.</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"> Optional</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> Type</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">callbacks </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</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"> AsyncCallbackManagerForToolRun</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"> CallbackManagerForToolRun</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 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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> BaseTool</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"> pydantic </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> BaseModel</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> Field</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)">class</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">CalculatorInput</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">BaseModel</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"> a</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)">int</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> Field</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"first number"</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"> b</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)">int</span><span class="token plain"> </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> Field</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">description</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"second number"</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)"># Note: It's important that every field has type hints. BaseTool is a</span><span class="token plain"></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)"># Pydantic class and not having type hints can lead to unexpected behavior.</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)">class</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">CustomCalculatorTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">BaseTool</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"> name</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><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)">"Calculator"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> description</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><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)">"useful for when you need to answer questions about math"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> args_schema</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> Type</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">BaseModel</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"> CalculatorInput</span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> return_direct</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)">bool</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 boolean">True</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)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">_run</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"> self</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> run_manager</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> Optional</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">CallbackManagerForToolRun</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 boolean">None</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><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">str</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Use the tool."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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)">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)">_arun</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"> self</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"> a</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)">int</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"> b</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)">int</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"> run_manager</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> Optional</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token plain">AsyncCallbackManagerForToolRun</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 boolean">None</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><span class="token operator" style="color:rgb(0, 0, 0)">-</span><span class="token operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">str</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Use the tool asynchronously."""</span><span class="token plain"></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)"># If the calculation is cheap, you can just delegate to the sync implementation</span><span class="token plain"></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)"># as shown below.</span><span class="token plain"></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)"># If the sync calculation is expensive, you should delete the entire _arun method.</span><span class="token plain"></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)"># LangChain will automatically provide a better implementation that will</span><span class="token plain"></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)"># kick off the task in a thread to make sure it doesn't block other async code.</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"> self</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">_run</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> run_manager</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">run_manager</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">get_sync</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/callbacks/langchain_core.callbacks.manager.AsyncCallbackManagerForToolRun.html">AsyncCallbackManagerForToolRun</a> | </span><span><a href="https://python.langchain.com/api_reference/core/callbacks/langchain_core.callbacks.manager.CallbackManagerForToolRun.html">CallbackManagerForToolRun</a> | </span><span><a href="https://python.langchain.com/api_reference/core/tools/langchain_core.tools.base.BaseTool.html">BaseTool</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">multiply </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> CustomCalculatorTool</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">name</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">description</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">args</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">return_direct</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">multiply</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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"></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 keyword" style="color:rgb(0, 0, 255)">await</span><span class="token plain"> multiply</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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">Calculator</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">useful for when you need to answer questions about math</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">{'a': {'description': 'first number', 'title': 'A', 'type': 'integer'}, 'b': {'description': 'second number', 'title': 'B', 'type': 'integer'}}</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">True</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">6</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">6</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="how-to-create-async-tools">How to create async tools<a href="#how-to-create-async-tools" class="hash-link" aria-label="Direct link to How to create async tools" title="Direct link to How to create async tools"></a></h2> <p>LangChain Tools implement the <a href="https://python.langchain.com/api_reference/core/runnables/langchain_core.runnables.base.Runnable.html" target="_blank" rel="noopener noreferrer">Runnable interface 🏃</a>.</p> <p>All Runnables expose the <code>invoke</code> and <code>ainvoke</code> methods (as well as other methods like <code>batch</code>, <code>abatch</code>, <code>astream</code> etc).</p> <p>So even if you only provide an <code>sync</code> implementation of a tool, you could still use the <code>ainvoke</code> interface, but there are some important things to know:</p> <ul> <li>LangChain's by default provides an async implementation that assumes that the function is expensive to compute, so it'll delegate execution to another thread.</li> <li>If you're working in an async codebase, you should create async tools rather than sync tools, to avoid incuring a small overhead due to that thread.</li> <li>If you need both sync and async implementations, use <code>StructuredTool.from_function</code> or sub-class from <code>BaseTool</code>.</li> <li>If implementing both sync and async, and the sync code is fast to run, override the default LangChain async implementation and simply call the sync code.</li> <li>You CANNOT and SHOULD NOT use the sync <code>invoke</code> with an <code>async</code> tool.</li> </ul> <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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> StructuredTool</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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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">calculator </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">multiply</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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"></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"></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)">await</span><span class="token plain"> calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</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><span class="token comment" style="color:rgb(0, 128, 0)"># Uses default LangChain async implementation incurs small overhead</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/tools/langchain_core.tools.structured.StructuredTool.html">StructuredTool</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">6</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">10</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)">from</span><span class="token plain"> langchain_core</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> StructuredTool</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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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)">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)">amultiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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">calculator </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> coroutine</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">amultiply</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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"></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"></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)">await</span><span class="token plain"> calculator</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">5</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><span class="token comment" style="color:rgb(0, 128, 0)"># Uses use provided amultiply without additional overhead</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/tools/langchain_core.tools.structured.StructuredTool.html">StructuredTool</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">6</span><br></span><span class="token-line" style="color:#000000"><span class="token plain">10</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>You should not and cannot use <code>.invoke</code> when providing only an async definition.</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</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)">multiply</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">a</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> b</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Multiply two numbers."""</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"> a </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> b</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)">try</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"> multiply</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)">"a"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">2</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)">"b"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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)">except</span><span class="token plain"> NotImplementedError</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)">print</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string" style="color:rgb(163, 21, 21)">"Raised not implemented error. You should not be doing this."</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">Raised not implemented error. You should not be doing this.</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="handling-tool-errors">Handling Tool Errors<a href="#handling-tool-errors" class="hash-link" aria-label="Direct link to Handling Tool Errors" title="Direct link to Handling Tool Errors"></a></h2> <p>If you're using tools with agents, you will likely need an error handling strategy, so the agent can recover from the error and continue execution.</p> <p>A simple strategy is to throw a <code>ToolException</code> from inside the tool and specify an error handler using <code>handle_tool_error</code>.</p> <p>When the error handler is specified, the exception will be caught and the error handler will decide which output to return from the tool.</p> <p>You can set <code>handle_tool_error</code> to <code>True</code>, a string value, or a function. If it's a function, the function should take a <code>ToolException</code> as a parameter and return a value.</p> <p>Please note that only raising a <code>ToolException</code> won't be effective. You need to first set the <code>handle_tool_error</code> of the tool because its default value is <code>False</code>.</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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> ToolException</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)">get_weather</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">city</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 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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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 triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Get weather for the given city."""</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)">raise</span><span class="token plain"> ToolException</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">f"Error: There is no city by the name of </span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation">city</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation 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 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/tools/langchain_core.tools.base.ToolException.html">ToolException</a></span></div> <p>Here's an example with the default <code>handle_tool_error=True</code> behavior.</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">get_weather_tool </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</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"> func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">get_weather</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"> handle_tool_error</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"></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">get_weather_tool</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)">"city"</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)">"foobar"</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">'Error: There is no city by the name of foobar.'</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 can set <code>handle_tool_error</code> to a string that will always be returned.</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">get_weather_tool </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</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"> func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">get_weather</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"> handle_tool_error</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"There is no such city, but it's probably above 0K there!"</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">get_weather_tool</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)">"city"</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)">"foobar"</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">"There is no such city, but it's probably above 0K there!"</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>Handling the error using a function:</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)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">_handle_error</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">error</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> ToolException</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">str</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 string-interpolation string" style="color:rgb(163, 21, 21)">f"The following errors occurred during tool execution: `</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation">error</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token string-interpolation interpolation">args</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token string-interpolation interpolation number" style="color:rgb(9, 134, 88)">0</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">]</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">`"</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">get_weather_tool </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> StructuredTool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">from_function</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"> func</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">get_weather</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"> handle_tool_error</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">_handle_error</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">get_weather_tool</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)">"city"</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)">"foobar"</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">'The following errors occurred during tool execution: `Error: There is no city by the name of foobar.`'</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="returning-artifacts-of-tool-execution">Returning artifacts of Tool execution<a href="#returning-artifacts-of-tool-execution" class="hash-link" aria-label="Direct link to Returning artifacts of Tool execution" title="Direct link to Returning artifacts of Tool execution"></a></h2> <p>Sometimes there are artifacts of a tool's execution that we want to make accessible to downstream components in our chain or agent, but that we don't want to expose to the model itself. For example if a tool returns custom objects like Documents, we may want to pass some view or metadata about this output to the model without passing the raw output to the model. At the same time, we may want to be able to access this full output elsewhere, for example in downstream tools.</p> <p>The Tool and <a href="https://python.langchain.com/api_reference/core/messages/langchain_core.messages.tool.ToolMessage.html" target="_blank" rel="noopener noreferrer">ToolMessage</a> interfaces make it possible to distinguish between the parts of the tool output meant for the model (this is the ToolMessage.content) and those parts which are meant for use outside the model (ToolMessage.artifact).</p> <div class="theme-admonition theme-admonition-info admonition_xJq3 alert alert--info"><div class="admonitionHeading_Gvgb"><span class="admonitionIcon_Rf37"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg></span>Requires <code>langchain-core >= 0.2.19</code></div><div class="admonitionContent_BuS1"><p>This functionality was added in <code>langchain-core == 0.2.19</code>. Please make sure your package is up to date.</p></div></div> <p>If we want our tool to distinguish between message content and other artifacts, we need to specify <code>response_format="content_and_artifact"</code> when defining our tool and make sure that we return a tuple of (content, artifact):</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"> random</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 </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> List</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> Tuple</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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> tool</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 decorator annotation punctuation" style="color:rgb(4, 81, 165)">@tool</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">response_format</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token string" style="color:rgb(163, 21, 21)">"content_and_artifact"</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)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">generate_random_ints</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token builtin" style="color:rgb(0, 112, 193)">min</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)">int</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)">max</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)">int</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> size</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> Tuple</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token builtin" style="color:rgb(0, 112, 193)">str</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> List</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token builtin" style="color:rgb(0, 112, 193)">int</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"> </span><span class="token triple-quoted-string string" style="color:rgb(163, 21, 21)">"""Generate size random ints in the range [min, max]."""</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> array </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">random</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">randint</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token builtin" style="color:rgb(0, 112, 193)">min</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)">max</span><span class="token punctuation" style="color:rgb(4, 81, 165)">)</span><span class="token plain"> </span><span class="token keyword" style="color:rgb(0, 0, 255)">for</span><span class="token plain"> _ </span><span class="token keyword" style="color:rgb(0, 0, 255)">in</span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">range</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">size</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"> content </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">f"Successfully generated array of </span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation">size</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)"> random ints in [</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation builtin" style="color:rgb(0, 112, 193)">min</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">, </span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation builtin" style="color:rgb(0, 112, 193)">max</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">]."</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"> content</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> array</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/tools/langchain_core.tools.convert.tool.html">tool</a></span></div> <p>If we invoke our tool directly with the tool arguments, we'll get back just the content part of the output:</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">generate_random_ints</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)">"min"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">0</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)">"max"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">9</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)">"size"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">10</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">'Successfully generated array of 10 random ints in [0, 9].'</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 we invoke our tool with a ToolCall (like the ones generated by tool-calling models), we'll get back a ToolMessage that contains both the content and artifact generated by the Tool:</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">generate_random_ints</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"> </span><span class="token string" style="color:rgb(163, 21, 21)">"name"</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)">"generate_random_ints"</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)">"args"</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)">"min"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">0</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)">"max"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">9</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)">"size"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">10</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 string" style="color:rgb(163, 21, 21)">"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)">"123"</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)"># required</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)">"type"</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)">"tool_call"</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)"># required</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 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">ToolMessage(content='Successfully generated array of 10 random ints in [0, 9].', name='generate_random_ints', tool_call_id='123', artifact=[4, 8, 2, 4, 1, 0, 9, 5, 8, 1])</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 can do the same when subclassing BaseTool:</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">tools </span><span class="token keyword" style="color:rgb(0, 0, 255)">import</span><span class="token plain"> BaseTool</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)">class</span><span class="token plain"> </span><span class="token class-name" style="color:rgb(38, 127, 153)">GenerateRandomFloats</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">BaseTool</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"> name</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><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)">"generate_random_floats"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> description</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><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)">"Generate size random floats in the range [min, max]."</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> response_format</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><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)">"content_and_artifact"</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"> ndigits</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)">int</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 number" style="color:rgb(9, 134, 88)">2</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)">def</span><span class="token plain"> </span><span class="token function" style="color:rgb(0, 0, 255)">_run</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">self</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)">min</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)">float</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)">max</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)">float</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> size</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)">int</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 operator" style="color:rgb(0, 0, 0)">></span><span class="token plain"> Tuple</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token builtin" style="color:rgb(0, 112, 193)">str</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> List</span><span class="token punctuation" style="color:rgb(4, 81, 165)">[</span><span class="token builtin" style="color:rgb(0, 112, 193)">float</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"> range_ </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">max</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 builtin" style="color:rgb(0, 112, 193)">min</span><span class="token plain"></span><br></span><span class="token-line" style="color:#000000"><span class="token plain"> array </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"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">round</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token builtin" style="color:rgb(0, 112, 193)">min</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 punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">range_ </span><span class="token operator" style="color:rgb(0, 0, 0)">*</span><span class="token plain"> random</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">random</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 punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> ndigits</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain">self</span><span class="token punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token plain">ndigits</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)">for</span><span class="token plain"> _ </span><span class="token keyword" style="color:rgb(0, 0, 255)">in</span><span class="token plain"> </span><span class="token builtin" style="color:rgb(0, 112, 193)">range</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">size</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"> content </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> </span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">f"Generated </span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation">size</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)"> floats in [</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation builtin" style="color:rgb(0, 112, 193)">min</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">, </span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation builtin" style="color:rgb(0, 112, 193)">max</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)">], rounded to </span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">{</span><span class="token string-interpolation interpolation">self</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">.</span><span class="token string-interpolation interpolation">ndigits</span><span class="token string-interpolation interpolation punctuation" style="color:rgb(4, 81, 165)">}</span><span class="token string-interpolation string" style="color:rgb(163, 21, 21)"> decimals."</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"> content</span><span class="token punctuation" style="color:rgb(4, 81, 165)">,</span><span class="token plain"> array</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)"># Optionally define an equivalent async method</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 def _arun(self, min: float, max: float, size: int) -> Tuple[str, List[float]]:</span><span class="token plain"></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)"># ...</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/tools/langchain_core.tools.base.BaseTool.html">BaseTool</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">rand_gen </span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token plain"> GenerateRandomFloats</span><span class="token punctuation" style="color:rgb(4, 81, 165)">(</span><span class="token plain">ndigits</span><span class="token operator" style="color:rgb(0, 0, 0)">=</span><span class="token number" style="color:rgb(9, 134, 88)">4</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">rand_gen</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"> </span><span class="token string" style="color:rgb(163, 21, 21)">"name"</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)">"generate_random_floats"</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)">"args"</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)">"min"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">0.1</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)">"max"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3.3333</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)">"size"</span><span class="token punctuation" style="color:rgb(4, 81, 165)">:</span><span class="token plain"> </span><span class="token number" style="color:rgb(9, 134, 88)">3</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 string" style="color:rgb(163, 21, 21)">"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)">"123"</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)">"type"</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)">"tool_call"</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 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">ToolMessage(content='Generated 3 floats in [0.1, 3.3333], rounded to 4 decimals.', name='generate_random_floats', tool_call_id='123', artifact=[1.5566, 0.5134, 2.7914])</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><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/how_to/custom_tools.ipynb" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" 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