Bevy 0.19 — Core concepts (App, Plugin, Schedule, World)

When to use this skill

• Setting up a new Bevy app or library plugin.
• Deciding which schedule (Startup, Update, FixedUpdate, PostUpdate, ...) a system belongs in.
• Writing an exclusive system that needs &mut World.
• Hitting schedule cycles, elevated ambiguity diagnostics, or deferred-command order bugs.
• Asking "where should X run?"

Canonical pattern

use bevy::prelude::*;