> For the complete documentation index, see [llms.txt](https://docs.eiffel.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.eiffel.dev/fundamentals.md).

# Fundamentals

- [Persistence](https://docs.eiffel.dev/fundamentals/persistence.md): Repository base class and other requirements.
- [Modelling](https://docs.eiffel.dev/fundamentals/modelling.md)