> For the complete documentation index, see [llms.txt](https://docs.aisuru.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aisuru.com/en/advanced-features/integrations/functions/what-are-functions.md).

# What are tools

The tools in AIsuru let your agent extend its capabilities beyond simple conversation. There are two main types of tools:

1. Built in tools (**"AIsuru Functions"**):
   1. Pre configured tools that are ready to use
   2. Include features like sending emails and searching the web
   3. Easy to enable and use without complex configuration
2. Custom tools (**"Advanced functions"**):
   1. Let you create custom integrations with external services
   2. Allow you to automate complex processes
   3. Require more detailed technical configuration

With the tools you can:

* Retrieve information from external sources in real time
* Automate repetitive actions
* Customize the Agent's responses based on specific data
* Integrate the Agent with other systems and services

In the next sections we'll explore in detail:

* The [built in tools ](/en/advanced-features/integrations/functions/aisuru-functions.md)available in AIsuru
* How to configure and use [advanced functions](/en/advanced-features/integrations/functions/advanced-functions.md) for specific use cases