# Cast and Geenius OS profiles

> How the cast works in Author: characters, places and objects made in Author or linked from Geenius OS profiles, roles, snapshots and what happens when a profile changes.

Source: https://author.geenius.io/docs/cast-and-profiles/

The **cast** of a book is the characters, places, objects, weather and organisations the story uses.

## Two ways to make a cast member

1. **In Author.** Make a character, place, object, weather or organisation directly. It belongs to your workspace and is never touched by a Geenius OS sync.
2. **From Geenius OS.** Link a profile from your Geenius OS Profiles. The cast then holds a **reference** to the profile and its revision. The profile stays in the OS; you describe a person once and use them in every book.

Geenius OS is optional. You can write a whole book without it.

## Roles

A cast entry can have a role: protagonist, antagonist, supporting, minor, narrator, setting, object, weather or organisation, and a note.

## Snapshots

Author keeps a **snapshot** of each linked profile: its revision, kind, name, summary, facets and its `located_in` and `part_of` relations. So a book opens and checks **without a network call**.

- A sync reads the profiles from Geenius OS as you, with a short-lived token. It runs from **Sync from Geenius OS**, by itself when the snapshots are more than ten minutes old, and before any action that names a profile.
- A newer revision in the OS shows on the cast as **changed in Geenius OS**.
- A profile deleted in the OS stays as a snapshot marked **missing**, so the book still reads.
- **Settings, Geenius OS** picks the workspace the profiles come from.

## Facts and story

Facts about a person (their birth date, their occupation) live in the profile. What happens to them in the story lives in Author as events. The state of a character at a moment is the profile plus the events up to then. See [Events and state](/docs/events-and-state/).

## Permissions

Linking uses a read-only permission for your Geenius OS profiles, granted when you sign in with Geenius OS. Author stores the permission sealed.