# Source: https://docs.crewai.com/en/tools/ai-ml/langchaintool.md

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.crewai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# LangChain Tool

> The `LangChainTool` is a wrapper for LangChain tools and query engines.

## `LangChainTool`

<Info>
  CrewAI seamlessly integrates with LangChain's comprehensive [list of tools](https://python.langchain.com/docs/integrations/tools/), all of which can be used with CrewAI.
</Info>

```python Code theme={null}
import os
from dotenv import load_dotenv
from crewai import Agent, Task, Crew
from crewai.tools import BaseTool
from pydantic import Field
from langchain_community.utilities import GoogleSerperAPIWrapper

# Set up your SERPER_API_KEY key in an .env file, eg:
# SERPER_API_KEY=<your api key>
load_dotenv()

search = GoogleSerperAPIWrapper()

class SearchTool(BaseTool):
    name: str = "Search"
    description: str = "Useful for search-based queries. Use this to find current information about markets, companies, and trends."
    search: GoogleSerperAPIWrapper = Field(default_factory=GoogleSerperAPIWrapper)

    def _run(self, query: str) -> str:
        """Execute the search query and return results"""
        try:
            return self.search.run(query)
        except Exception as e:
            return f"Error performing search: {str(e)}"

# Create Agents
researcher = Agent(
    role='Research Analyst',
    goal='Gather current market data and trends',
    backstory="""You are an expert research analyst with years of experience in
    gathering market intelligence. You're known for your ability to find
    relevant and up-to-date market information and present it in a clear,
    actionable format.""",
    tools=[SearchTool()],
    verbose=True
)

# rest of the code ...
```

## Conclusion

Tools are pivotal in extending the capabilities of CrewAI agents, enabling them to undertake a broad spectrum of tasks and collaborate effectively.
When building solutions with CrewAI, leverage both custom and existing tools to empower your agents and enhance the AI ecosystem. Consider utilizing error handling, caching mechanisms,
and the flexibility of tool arguments to optimize your agents' performance and capabilities.