# Systems

> For agents: start with the [agent guide](https://parol6.build/llms.txt). Every page is Markdown by default; add `Accept: text/html` for HTML.

Each shipped system has a page with its behavior, standard, and checks.

- [Motion](/systems/motion) — @rat-stack/motion gives Foldkit apps Penner and CSS easings, tweens, fixed-step springs and interpolation, held in the Model and checked by properties.