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

# CORE CONCEPTS

- [What is Portex?](https://docs.portexai.com/portex-docs/core-concepts/readme.md): Expert-authored evals for state-of-the-art AI models.
- [How Evals Work](https://docs.portexai.com/portex-docs/core-concepts/how-evals-work.md): A conceptual overview of Portex Evals and how they work.
- [PSDLA](https://docs.portexai.com/portex-docs/core-concepts/psdla.md): The Portex Standard Data License Agreement (PSDLA) is an open source data license framework.