Langchain Tool Decorator. Issue Content from langchain_core. The run logging spec can be found

Issue Content from langchain_core. The run logging spec can be found in the LangSmith SDK repository. Understand their key importance in AI development. Retrieval tools are not limited to a single string query argument, as in the above example. The LangChain framework integrates seamlessly with LangSmith, our platform for agent observability, evaluation, and deployment — you can set just one environment variable to get started. You decide if the handler is called zero times (short-circuit), once (normal flow), or multiple times (retry logic). Additionally, the decorator will use the function's docstring as the tool's description. LangChain 装饰器是 LangChain 之上的一层，为编写自定义 LangChain 提示词和链提供了语法糖 🍭 如需反馈、问题、贡献 - 请在此提出问题： ju-bezdek/langchain-decorators 主要原则和好处：更加 pythonic 的编写代码方式编写多行提示词，避免因缩进而中断代码流程 Nov 27, 2025 · import datetime from pydantic import BaseModel from langchain_decorators import llm_prompt, llm_function, LlmChatSession # from langchain. @chain decorator. messages import ToolMessage def tool_node(state: dict): """Performs the tool call""" result = [] for tool_call in state["messages"][-1]. Graduate to multi-agent patterns only when you hit clear limits. from langchain. 190 Redirecting May 20, 2024 · In this article, we will explore various methods for creating tools (customized tools) within the LangChain framework that can be utilized by chains/agents, or other components. This is functionaly equivalent to wrapping in a RunnableLambda. langchain. LangChain provides the engineering platform and open source frameworks developers use to build, test, and deploy reliable AI agents. runnables import chain from langchain_openai import ChatOpenAI prompt1 = ChatPromptTemplate. 190 Redirecting Nov 30, 2023 · The @tool decorator in LangChain creates a Custom Tool from a simple function. It makes it easier to write multiline prompts, define optional parameters Intercept execution and control when the handler is called. Product teams evaluating LangChain, LangFlow, or custom agent frameworks This session is technical in nature and assumes basic programming familiarity. runnables import RunnableLambda # 파이썬 코드를 실행하고 중간 과정을 출력하고 도구 실행 결과를 반환하는 함수 def print_and_execute (code Aug 16, 2024 · In this tutorial, we will explore how to build a multi-tool agent using LangGraph within the LangChain framework to get a better… May 29, 2025 · The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package). When a function is decorated with @tool, it becomes available to agents that can intelligently select and use tools based on the task. May 14, 2025 · There are two ways to create a tool: using @tool or Tool from the langchain_core. output_parsers import StrOutputParser from langchain_core. Sep 2, 2025 · The @tool decorator offers a straightforward way to turn Python functions into LangChain tools. However, in many real-world projects, we’ll often find that only so many requirements can be satisfied by existing tools. invoke("What is 2 times 3?") Participate in DataHour, a series of live sessions by industry experts to expand your skills in GenAI, data science, and machine learning. Convert Python functions and Runnables to LangChain tools. Using the @tool Decorator The quickest way to turn a regular Python function into a LangChain Tool is to add the @tool decorator. Modify existing tools (修改现有工具) 6. 1 day ago · Why LangChain and LangGraph Remote chose LangChain because its ecosystem offers mature abstractions for prompt handling and tool invocation. from langchain_openai import ChatOpenAI from langchain_core. Learn how to define your own custom tools to give agents new capabilities, such as interacting with a specific API. Handling Tool Errors (处理工具 LangChain Redirecting Multi-agent systems coordinate specialized components to tackle complex workflows. Aug 13, 2024 · Beginner tutorial on how to design, create powerful, tool-calling AI agents chatbot workflow with LangGraph and LangChain. We would like to show you a description here but the site won’t allow us. Design simple and narrowly scoped tools, as they are easier for models to use correctly. Jul 9, 2025 · Troubleshoot LangChain and LangGraph tracing issues with common causes and clear fixes to keep your observability on point. The tool decorator is an easy way to create tools. Using tools to return directly (使用工具直接返回) 8. We built one of the first chains based on ReAct, a groundbreaking paper that brought tool use to the forefront of prompting frameworks. Apply now for this remote hr & recruiting opportunity. Dec 30, 2024 · Unpacking Tools and Chains with LangChain Data Mastery Series — Episode 42: LangChain Website (Part 17) Connect with me and follow our journey: Linkedin, Facebook Welcome back to the Data 2. You need control, logging, retries, dynamic behaviours, caching, metrics, and enforcement of policies. LangChain is an open source framework with a pre-built agent architecture and integrations for any model or tool — so you can build agents that adapt as fast as the ecosystem evolves LangChain is an open source framework with a pre-built agent architecture and integrations for any model or tool — so you can build agents that adapt as fast as the ecosystem evolves Ready to start shipping u2028reliable agents faster? Get started with tools from the LangChain product suite for every step of the agent development lifecycle. append(ToolMessage(content=observation, tool_call_id=tool_call["id"])) return {"messages LangChain is an open source framework with pre-built agent architectures and as integrations to models, tools, and databases to start building agents quickly. Compare features, prices, and use cases to find the best alternative to LangChain for your needs. 1 day ago · Today, both LangChain and LangGraph rely on ad‑hoc PyTest patterns, manual mocks, and custom assertions. 2. LangChain 装饰器是 LangChain 之上的一层，为编写自定义的 langchain prompt 和 chain 提供了简化的语法糖 🍭 Tools should be well-documented: their name, description, and argument names become part of the model’s prompt. To make it easier to define custom tools, a @tool decorator is provided. However, at the source code level, they would all be built and defined using a similar methods as described above. LLM Playground is a tool for testing and iterating on your prompts and model configurations, shortening the feedback loop and accelerating development. Welcome to LangChain — 🦜🔗 LangChain 0. The simplest way to create a tool is with the @tool decorator. San Francisco. Key Capabilities: LangChain is an open source framework with a pre-built agent architecture and integrations for any model or tool — so you can build agents that adapt as fast as the ecosystem evolves Decorators offer a simplified variant that manages this for you. com Redirecting We would like to show you a description here but the site won’t allow us. Your community starts here. 0. You can use either the native LangChain @tool decorator or @llm_function, which adds conveniences such as handling bound methods and allowing dynamic tool schema generation (especially useful for passing dynamic argument domain values). Use chat models that support tool-calling APIs Asking the model to select from a large list of tools poses Jun 11, 2023 · LangChain Decorators is a Python library that provides syntactic sugar for writing custom Langchain prompts and chains. Oct 24, 2024 · How to build Custom Tools in LangChain 1: Using @tool decorator: There are several ways to build custom tools. improved observability by tracing your chain correctly Any calls to runnables inside this function will be traced as nested childen. tool module. 1 day ago · Talent Operations Programs Manager position at LangChain, Inc. Connect with builders who understand your journey. By simply wrapping a function, it automatically assigns key attributes like the tool's name and description, pulling these details from the function's name and docstring. What is a Tool? A tool in CrewAI is a skill or function that agents can utilize to perform various actions. For distinctions between each approach, we encourage you to reference the official LangChain documentation. Contribute to langchain-ai/langgraph development by creating an account on GitHub. Share solutions, influence AWS product development, and access useful content that accelerates your growth. However, not every complex task requires this approach — a single agent with the right (sometimes dynamic) tools and prompt can often achieve similar results. bind_tools([multiply]) # Invoke the LLM with input that triggers the tool call msg = llm_with_tools. python. Its core components are Tools and Agents. Using the tool decorator (使用工具修饰器) 4. A collection of Tools in LangChain are called a Toolkit. There is no unified, first‑class testing framework that supports deterministic LLM mocking, chain/graph assertions, snapshot testing, or workflow‑level validation. I posted a self-contained, minimal, reproducible example. Prerequisites Basic knowledge of Python or JavaScript Familiarity with LLM concepts (prompts, tokens, tools) Optional but helpful: Prior attendance of "Build Your First AI Agent – Part 1" 从函数创建工具 @tool 装饰器这个 @tool 装饰器是定义自定义工具最简单的方法。默认情况下，装饰器使用函数名作为工具名，但可以通过将字符串作为第一个参数传递来覆盖。此外，装饰器将使用函数的文档字符串作为工具的描述——因此必须提供文档字符串。 Apr 10, 2024 · We can build out tools as needed, depending on the nature of tasks we are trying to carry out with the agent to fulfil. LangChain is an open source framework with a pre-built agent architecture and integrations for any model or tool — so you can build agents that adapt as fast as the ecosystem evolves Aug 3, 2024 · tool: This is a decorator provided by LangChain to define custom tools easily. And that is it as far as our Tools our concerned. 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. use this as any other runnable, compose it in chain, etc. tools. Meaning we must modify existing tools or build entirely new ones. Custom Structured Tools (定制结构化工具) 5. This includes tools from the CrewAI Toolkit and LangChain Tools, enabling everything from simple searches to complex interactions and effective teamwork among agents. Nov 5, 2024 · How to enable tools use in LangChain Some best practices to design a tool are as follows: Tools that are well-named, correctly-documented and properly type-hinted are easier for models to use. Defining the priorities among Tools (定义工具之间的优先级) 7. tools import tool as langchain_tool # example placeholder if needed class Agent(BaseModel): customer_name: str # bound properties/fields on instances are accessible in the prompt @property def current_time This guide explains how to create a custom LangChain tool for retrieving flight status details. com Redirecting %pip install --upgrade --quiet langchain langchain-openai from langchain_core. By applying the principles laid out in this guide, you can transform your approach to creating clever prompts and insightful chains. LangChain’s @tool decorator adds metadata and enables runtime injection via the ToolRuntime parameter. Dec 30, 2025 · LangChain is a framework for building LLM applications with components for models, tools, retrieval, and agent-style execution. Can be used as a decorator with or without arguments to create tools from functions. Functions can have any signature - the tool will automatically infer input schemas unless disabled. tool_calls: tool = tools_by_name[tool_call["name"]] observation = tool. May 2, 2023 · Way back in November 2022 when we first launched LangChain, agent and tool utilization played a central role in our design. Oct 18, 2024 · Privileged issue I am a LangChain maintainer, or was asked directly by a LangChain maintainer to create an issue here. Here's how: Tracing without LangChain: learn to trace applications independent of LangChain using the Python SDK's @traceable decorator. 1 day ago · This course helped me understand how to build Agentic AI systems using LangChain, including working with LLMs, tools, memory, and intelligent agents to create autonomous AI workflows. For flexible customization, the @tool decorator is more useful, so we’ll use that. . LangChain will automatically expose the function to Agents/Chains. The decorator uses the function name as the tool name by default, but this can be overridden by LangChain is an open source framework with a pre-built agent architecture and integrations for any model or tool — so you can build agents that adapt as fast as the ecosystem evolves May 22, 2025 · Learn how to create, register, and use custom tools in LangChain with practical examples, best practices, and step-by-step instructions. Apr 10, 2024 · So we have defined our own three custom tools. from_function function in the LangChain framework. 6 days ago · In this post, we’ll explore when multi-agent architectures become necessary, the four main patterns we’ve observed, and how LangChain empowers you to effectively build multi-agent systems. What matters for this comparison is that LangChain’s agent runtime is graph-based and built using LangGraph. Key concepts Tools are a way to encapsulate a function and its schema in a way that can be passed to a chat model. - langflow-ai/langflow Build resilient language agents as graphs. Async tools can be created by using the StructuredTool or the BaseTool classes. Custom tools can be defined by using various methods including using the @tool decorator or LangChain Runnables which we'll cover in this tutorial. Tools extend the capabilities of LLMs, while agents orchestrate tools to solve complex tasks intelligently. It simplifies the process of turning functions into tools that can be used by an agent. They support continuous improvement, pre-deployment testing, structured experiments, flexible evaluation, and seamless integration with frameworks like LangChain and LlamaIndex. It provides essential tools for managing workflows, maintaining context, and integrating with external systems, streamlining the development of AI-powered applications. Dec 26, 2025 · Explore AI Agent Frameworks like Langchain, CrewAI, and Microsoft Semantic Kernel. This will let us access document metadata in our application, separate from the stringified representation that is sent to the model. Available hooks: wrap_model_call - Around each model call wrap_tool_call - Around each tool call Example: Decorator Class Created by Harrison Chase & Ankush Gola in San Francisco, LangChain and LangGraph are developer toolkits designed to turn AI models into functional apps. 190 Redirecting Here are the Top 7 Python Frameworks every developer must know in 2025! From LangChain to SuperAGI – these tools are changing the AI game 🤯💻 🚀 Learn, build, and innovate faster than ever! Save this reel for later & share it with your dev squad! 👨‍💻 Comment “AI 🔥” if you want a Part 2! python. Subclassing the BaseTool class 3. 1, max_tokens=1000, timeout=30 # (other params) ) agent = create_agent(model, tools=tools) Here we use the tool decorator to configure the tool to attach raw documents as artifacts to each ToolMessage. Jul 9, 2024 · This article discovers how to use LangChain with MyScale to build advanced AI agents. Create tools using the @tool decorator, which simplifies the process of tool creation, supporting the following: Automatically infer the tool's name, description and expected arguments, while also supporting customization. 5 days ago · LangChain's Deep Agents offers an out-of-the-box implementation combining subagents and skills for teams wanting to start quickly. REST API: get acquainted with the REST API's features for logging LLM and chat model runs, and understand nested runs. You can use zod to define the tool’s input schema: Building good agents 📊 Inspect your agent runs using telemetry 🛠️ Tools - in-depth guide 🛡️ Secure code execution 📚 Manage your agent's memory Aug 12, 2022 · LangChain Decorators serve as a powerful companion for anyone looking to enhance their workflow with LangChain. tools import tool class MyAPI: def __init__( Welcome to LangChain — 🦜🔗 LangChain 0. Sep 24, 2025 · In this article, we’ll walk through two categories of tools in LangChain — built-in tools and custom tools, and then dive into how to create structured tools using Pydantic. These providers have standalone langchain-provider packages for improved versioning Mar 19, 2025 · LangChain’s LangGraph Platform allows Qualtrics to design, deploy, and manage complex generative AI agent workflows with the efficiency and scale required. invoke(tool_call["args"]) result. A provider is a third-party service or platform that LangChain integrates with to access AI capabilities like chat models, embeddings, and vector stores. This decorator can be used to quickly create a Tool from a simple function. 📋 Description • Be the architect of LangChain’s next-level hiring machine. from_template("Tell me a joke about {topic}") python. The LangChain library provides a substantial selection of prebuilt tools. LangChain is an open source framework with a pre-built agent architecture and integrations for any model or tool — so you can build agents that adapt as fast as the ecosystem evolves 1 day ago · What is LangChain? LangChain is a powerful, open-source framework for developing applications powered by large language models (LLMs). Jul 14, 2023 · From what I understand, you requested that the handle_tool_error and return_direct kwargs be made available in both the @tool decorator and the Tool. 3 days ago · When building real-world agent systems, you often need more than the default agent pipeline. tool: This is a decorator provided by LangChain to define custom tools easily. Aug 7, 2024 · In the realm of LLM frameworks , LangChain offers an underrated feature for connecting Large Language Models (LLMs) with various tools, One of its intriguing features is the Shell/Bash tool, which Create tools Basic tool definition The simplest way to create a tool is by importing the tool function from the langchain package. Sep 1, 2025 · LangChain is a framework for building applications with Large Language Models (LLMs). LangChain (launched in 2022) is the tl;dr; - turn any Python function into an OpenAI function with `@llm_function` decorator - the function description will be generated by mixing the… 5 days ago · Boost your future-ready skills with Best Agentic AI certification and training courses led by industry experts, featuring hands-on labs, real-world applications, and autonomous AI systems. Use for retries, caching, and transformation. Apr 25, 2024 · LangChain provides standard Tool Calling approach to many LLM providers like Anthropic, Cohere, Google, Mistral, and OpenAI support variants of this tool calling feature. prompts import ChatPromptTemplate from langchain_core. By default, the function’s docstring becomes the tool’s description that helps the model understand when to use it: May 16, 2025 · The tool decorator is a core part of the LangChain architecture, enabling seamless integration between functions and language model agents. But the core advice remains pragmatic: add tools before adding agents. LangChain offers an extensive ecosystem with 1000+ integrations across chat & embedding models, tools & toolkits, document loaders, vector stores, and more. Use the @tool decorator to quickly create a Tool without needing advanced customization or defining custom instance variables. Learn about integrating language models for improved data processing and decision-making. This chapter will explore how to build custom tools for agents in LangChain. Tools: External functions, APIs or logic that an agent can call. Its modular design allowed the team to integrate multiple model providers and build on a standard interface instead of rolling out their own. Langflow is a powerful tool for building and deploying AI-powered agents and workflows. agents import create_agent from langchain_openai import ChatOpenAI model = ChatOpenAI( model="gpt-5", temperature=0. # Define a tool def multiply(a: int, b: int) -> int: return a * b # Augment the LLM with tools llm_with_tools = llm. Unified reference documentation for LangChain and LangGraph Python packages. You will own every gear— Jan 9, 2026 · Learn about the best LangChain alternatives in 2026. A more common use case might be to use some of the already provided and existing tools in LangChain, which you can see here. LangChain decorators is a layer on the top of LangChain that provides syntactic sugar 🍭 for writing custom langchain prompts and chains For Feedback, Issues, Contributions - please raise an issue here: ju-bezdek/langchain-decorators Main principles and benefits: more pythonic way of writing code Welcome to LangChain — 🦜🔗 LangChain 0. Jun 20, 2024 · Langchain library provides @tool decorator which is the simplest way to define a custom tool.

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