# Building blocks

The classes models are made of. Use them to add viruses, interventions, or
groups to a model, or to build a custom model from an empty
{class}`~epiworldpy.Model`.

```{eval-rst}
.. currentmodule:: epiworldpy

.. autosummary::
   :toctree: generated
   :template: class.rst
   :nosignatures:

   Model
   Agent
   Virus
   Tool
   Entity
   UpdateFun
   NativeUpdateFun
```