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

# Guard

Guards are the building blocks of Guardrails. Each Guard performs specific checks and/or transformations on the data. For instance, a Guard in an input Guardrail can check for security, while a Guard in an output Guardrail might check for moderation or privacy.

A Guard belongs to one of the following categories:

* Security
* Moderation
* Privacy
* Integrity
* Generic

Guards consist of a set of [Detectors](/core-concepts/components/detector) and how they should be executed.