## State: World vs Player

**World flags** (`set_flags`, checked with `flag`) are shared by every player on the server. A door opened by one player is open for everyone. A lever pulled once changes the world for all.

**Player flags** (`set_player_flags`, checked with `player_flag`) are per-character. Quest progress, "has read the sign," "paid the toll" — these are different for each player. Saved to the character YAML and persist across logins.

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