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Bevy App Resources
Docs-first stub for Bevy app-wide resources and schedules. Godot counterpart: godot-autoload-architecture. Not a full port. Keywords: Bevy, Resource, App, Schedule, Plugin.
Archived 2026-10-23 · Source updated 2026-10-11 · License: LGPL-3.0. Check the original repository for the latest version.
SKILL.md instructions
# Bevy app resources (docs-first stub) Not a full port. App-wide data is a `Resource` on the `World`. There is no autoload and no singleton node. ## When to use Load this when data or logic must exist for the whole app: one clock, one ruleset, startup spawn, or an ordered pair of systems. Pair with bevy-data-resources for the component-versus-resource split. ## ECS shape - **App.** The Apps page: an `App` contains a `World` and the outer loop. It initializes resources (one copy), adds systems to a `Schedule`, and imports other `App` changes through plugins. - **Resources.** `Resource`, `Res`, `ResMut`, and `insert_resource` (Resources page). `Time` arrives from `add_plugins(DefaultPlugins)`. - **Plugins.** The Resources page implements `Plugin` and inserts the resource inside `build`. `DefaultPlugins` is the plugin set that adds `Time`. Do not add further plugin names in this stub. - **Schedules.** `add_systems(Startup, ...)` runs once before other systems. `add_systems(Update, ...)` is the repeating schedule in the ECS page. `.chain()` orders systems that must see each other's writes. `bevy::ecs::message` names `FixedUpdate` only as the schedule after which `signal_message_update_system` runs. Fixed-timestep clock types stay in bevy-character-movement. - **States.** App-wide modes are `bevy::state`, not a global node. See bevy-state-machines. ## Godot idea to Bevy idiom | Idea | Bevy idiom (idea only) | | --- | --- | | Autoload singleton | A `Resource` inserted on the `App` | | Global script that ticks | A system on `Update` (or a chained pair) | | Boot setup | A `Startup` system or `insert_resource` in a `Plugin` | | Cross-scene bus | A message or event. See bevy-events-messaging. Not a persistent node | ## Gaps - Plugin dependency order and groups were not opened. - Sub-apps were named on the state module (`SubApp`) and not opened here. - Save-game resources and settings files were not opened (`bevy_settings` is a feature name on the crate page only). ## Expert Knowledge Delta Library target in prose: **Bevy 0.20.0**. Lattice URLs stay unversioned. Opened canon only: `Component`, `Resource`, `Query`, `Commands`, `Startup`, `Update`, `Fixed` / `FixedMain` (`bevy::time`), `.chain()`, `Plugin`, `DefaultPlugins`, `MinimalPlugins`. Messages and observers are an ownership slot. This file does not invent their struct APIs. Systems run in parallel unless `.chain()` orders the ones that conflict. ### Who owns state | Piece | Owner | Who may mutate | Schedule | | --- | --- | --- | --- | | Data on one entity | `Component` | One system via `Query` | `Update` or `FixedMain` | | One value for the whole app | `Resource` | One system | `Startup` to insert, then the schedule that reads it | | Spawn | `Commands` | The spawning system | `Startup` for the initial world; later schedules for runtime spawn | | Order that must not race | `.chain()` | The chained systems only | Same schedule | | Plugin boundary | `Plugin` | `build` registers systems and resources | Before the app runs | Borrow rule: two systems that both mutably query the same component must be ordered (`.chain()`) or split so only one writes. Unrelated systems stay parallel. That is the ECS page rule, not a guess at a system-set API. ### Decision | If you need | Do this | Do not | | --- | --- | --- | | Per-entity data | `Component` + `Query` | A Godot node script | | App-wide config or clock | `Resource` | Copy the value onto every entity | | Stable simulation step | `FixedMain` and the `Fixed` clock | Tie simulation to raw frame `Update` | | Startup spawn | `Commands` in `Startup` | Spawn from a render system | | Cross-system notice that is not shared state | Message or observer slot in `bevy-events-messaging` | A new event type invented in this file | | An API this skill did not open | A Gaps row | A fabricated crate (solver, navmesh module, net, XR) | Load `references/a-gate-notes.md` for the same table plus the gap rule. ## NEVER - Do not put `/0.20.0/` in lattice URLs. WHY: permalinks stay on `latest`. The 0.20.0 pin belongs in prose once. - Do not mutably query the same component from two unordered systems. WHY: the schedule runs systems in parallel unless `.chain()` orders them. - Do not invent a physics, navigation, networking, or XR crate here. WHY: those rows are gaps, blocked, or revisit. - No autoload, singleton node, or signal bus. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No Godot types. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No invented plugin lists beyond `DefaultPlugins` and the `Plugin` trait the Resources page uses. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No third-party crates. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No Creation Station content. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No umbrella skill over Godot and Bevy. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - Do not mark this row `ported`. It is `docs_mapped`. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. ## Reference docs.rs links use the unversioned `latest` permalink. The library pin on bevy-master stays **0.20.0**. ### Official Documentation - [Migration guides](https://bevy.org/learn/migration-guides/introduction/) - Unversioned hop index. - [bevy crate](https://docs.rs/bevy/latest/bevy/) - Unversioned API index. `default_app` includes `bevy_state` and `bevy_log`. - [Apps](https://bevy.org/learn/quick-start/getting-started/apps/) - `App`, `World`, resources, `Schedule`, plugins. - [Resources](https://bevy.org/learn/quick-start/getting-started/resources/) - `Resource`, `insert_resource`, `Plugin::build`, `DefaultPlugins`, `Time`. - [Quick Start: ECS](https://bevy.org/learn/quick-start/getting-started/ecs/) - `Startup`, `Update`, `add_systems`, `.chain()`. - [Examples](https://github.com/bevyengine/bevy/tree/latest/examples#examples) - Example tree on the `latest` branch. ### Related Skills #### Prerequisites - [bevy-master](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-master/SKILL.md) - No autoload layer on top of the schedule. - [bevy-project-foundations](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-project-foundations/SKILL.md) - Crate and `App::new()`. #### Complements - [bevy-data-resources](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-data-resources/SKILL.md) - When data is a component instead of a resource. - [bevy-state-machines](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-state-machines/SKILL.md) - App-wide `States` instead of a global mode flag on a node. - [godot-autoload-architecture](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/godot-autoload-architecture/SKILL.md) - Godot counterpart. Source idea only. Do not import Godot types. #### Downstream / consumers - None yet. Save, audio, and scene skills are not ported. #### Master - [bevy-master](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-master/SKILL.md) - Bevy router.