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Bevy Save Load
Docs-first stub for Bevy persistence boundaries. Godot counterpart: godot-save-load-systems. Not a full port. Keywords: Bevy, save, Resource, Scene, AssetServer, gaps.
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 save and load (docs-first stub) Not a full port. This file records what was opened and what was not. There is no Bevy save-slot API in the pages below. ## When to use Load this when a design asks to persist player progress. Route asset and scene spawning to `bevy-asset-scenes`. Keep save bytes as an explicit gap until a current page names the format. ## ECS shape - **What exists:** app-wide progress can be a `Resource` (see `bevy-data-resources`). Level content loads through `AssetServer` and may spawn with `spawn_scene` / `queue_spawn_scene` (`bevy::scene`, docs.rs `latest`, 0.20.0). - **What was checked and rejected:** `https://docs.rs/bevy/latest/bevy/scene/struct.DynamicScene.html` returned 404 on 2026-10-11. The live scene index documents `Scene` and `bsn!`, not a save-file serializer. Do not call `DynamicScene::serialize` from this skill. - **Schedule:** no save system is specified here. Do not invent a filesystem write inside `Update`. ## Godot idea to Bevy idiom | Idea | Bevy idiom (idea only) | | --- | --- | | Resource file for designer data | An asset `Handle`, or a `Resource` you own in code | | Packed scene instance | `Scene` spawn on `bevy-asset-scenes` | | Player save slot | Not opened. Leave it as data you have not serialized yet | ## Gaps - No save path, slot index, version field, or RON/JSON writer was opened on docs.rs `latest`. - Scene spawn is not a save game. Do not treat `bsn!` as a user save. - Wasm has no general filesystem story on the pages opened for this batch. Do not invent one. ## 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 Godot `Resource`, `FileAccess`, or config-file types. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No `DynamicScene` or scene-file writer this file's opened pages do not list. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar. - No third-party save 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` because the gap was checked against live docs. 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. - [bevy::scene](https://docs.rs/bevy/latest/bevy/scene/index.html) - Spawn API that is not a save format. `DynamicScene` struct URL 404. - [bevy::asset](https://docs.rs/bevy/latest/bevy/asset/index.html) - Disk assets, not player slots. - [Resources](https://bevy.org/learn/quick-start/getting-started/resources/) - App-wide data that a future save would have to name. - [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) - Who owns which piece of state. - [bevy-data-resources](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-data-resources/SKILL.md) - `Resource` versus `Component`. - [bevy-asset-scenes](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-asset-scenes/SKILL.md) - Loading content. Not a save slot. #### Complements - [godot-save-load-systems](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/godot-save-load-systems/SKILL.md) - Godot counterpart. Source idea only. #### Downstream / consumers - None until a save format is opened. #### Master - [bevy-master](https://github.com/thedivergentai/gd-agentic-skills/blob/main/skills/bevy-master/SKILL.md) - Bevy router.