Graph World Bevy

GraphOS Skill: graph-world-bevy

Implement GraphOS world runtime in Rust with Bevy ECS/time only, without Bevy rendering, windowing, UI, or asset pipeline.

This skill depends on graph-world for graph modeling and closure validation, and on graph-management for graph inspection, validation, and atomic graph mutations. Use graph-world first whenever the request changes World/Context/Variant/System/Event/EventSystem topology, then use graph-management to read or apply the resulting graph changes.

Scope Boundary

• This skill covers GraphOS project bootstrap plus Rust runtime initialization.
• This skill does not include TypeScript implementation code.
• This skill does not include Bevy rendering stack (bevy_render, bevy_winit, bevy_pbr, bevy_ui, bevy_sprite, etc.).
• If the request includes rendering or frontend integration, hand off to another presentation/runtime skill.

When to Use

• You need a GraphOS world project with Rust runtime instead of TypeScript runtime.
• You need Bevy as ECS/runtime scheduler and time source only.
• You need a deterministic, headless app loop for world/domain logic.

Preconditions

1. Complete graph design with graph-world first.
2. Finish graph closed-loop validation before runtime coding.
3. Use graph-management to inspect graph state, validate node types/plugins, and apply any graph mutations before changing Rust runtime bindings.
4. If Graph changed, regenerate/update GraphOS outputs before changing Rust runtime bindings.

Project Bootstrap (GraphOS, No TypeScript Code)

Use this when initializing a new world project that still needs GraphOS CLI and graph metadata, but no TS runtime code.

1. Initialize npm metadata and GraphOS tooling:

npm init -y
npm i -D graphos-world-plugin graphos-cli

2. Ensure package.json contains GraphOS config with TS generators disabled:

{
  "type": "module",
  "graphos": {
    "world": {
      "genTypeScript": {
        "enabled": false,
        "outDir": "gen"
      },
      "genWebTypeScript": {
        "enabled": false,
        "outDir": "app"
      },
      "genCocosCreator": {
        "enabled": false,
        "outDir": "../cocos/assets/gen"
      },
      "genBevy": {
        "enabled": true,
        "outDir": "src/gen"
      }
    }
  }
}

3. Ensure package.json scripts includes GraphOS, wasm, and cross-compile commands:

{
  "scripts": {
    "graphos": "graphos",
    "build:wasm": "wasm-pack build . --target web --release --out-dir dist",
    "build:wasm:bundler": "wasm-pack build . --target bundler --release --out-dir dist",
    "build:wasm:node": "wasm-pack build . --target nodejs --release --out-dir dist",

    "build:ios:arm64": "cargo build --release --target aarch64-apple-ios",
    "build:ios:x86_64": "cargo build --release --target x86_64-apple-ios",
    "build:ios:arm64_sim": "cargo build --release --target aarch64-apple-ios-sim",

    "build:android:armv7": "cargo ndk -t armeabi-v7a build --release",
    "build:android:arm64": "cargo ndk -t arm64-v8a build --release",

    "build:macos:x86_64": "cargo build --release --target x86_64-apple-darwin",
    "build:macos:arm64": "cargo build --release --target aarch64-apple-darwin",

    "build:windows:x86_64": "cargo zigbuild --release --target x86_64-pc-windows-gnu",
    "build:linux:x86_64": "cargo zigbuild --release --target x86_64-unknown-linux-gnu"
  }
}

4. Create World.graph.json in project root:

{
  "id": "main",
  "name": "World",
  "nodes": [],
  "edges": []
}

5. Optional verification:

npm run graphos -- --help
npm run build:wasm:node
npm run build:macos:arm64

Completion checks:

• GraphOS CLI is available.
• Graph file exists.
• No TypeScript build/runtime files are required by this skill.
• wasm-pack build scripts are available in package.json.
• Cross-compile scripts exist for iOS/Android/macOS/Windows/Linux targets.

Rust + Bevy Initialization (Latest, Headless)

Goal: initialize a Rust runtime that uses Bevy ECS/time scheduling only.

Step 1: Initialize Rust crate in current directory

# Run this in the project root directory.
cargo init --bin .

If a Cargo project already exists in the current directory, skip this step.

Cargo.toml Rules (Mandatory)

Apply these rules in Cargo.toml for this skill:

1. package.name MUST be fixed to "app".
2. Library output MUST support both crate types: "cdylib" and "rlib" and "staticlib".

Example:

[package]
name = "app"

[lib]
crate-type = ["cdylib", "rlib", "staticlib"]

Step 2: Add world-bevy and Bevy runtime dependencies

cargo add world-bevy
cargo add bevy --no-default-features --features bevy_app,bevy_ecs,bevy_time

Fallback (if feature flags change in newer Bevy releases):

cargo add world-bevy
cargo add bevy_app bevy_ecs bevy_time

Rules:

• Always use the latest published versions.
• Do not enable rendering/window/UI-related features.
• Keep dependency set minimal: app, ecs, time.
• world-bevy is a mandatory dependency; do not skip it.
• See world-bevy Dependency below for what the crate provides.

world-bevy Dependency

cargo add world-bevy

What world-bevy provides

The project's src/core/mod.rs re-exports world-bevy types and adds project-specific helpers:

// src/core/mod.rs
pub use world_bevy::core::*;

use bevy_ecs::prelude::*;

#[derive(Event)]
pub struct WorldLogEvent {
    pub log: String,
}

This ensures that all world_bevy::core::* imports (used throughout src/gen and src/app) resolve to world_bevy::core types plus any project-local extensions.

Dependency rules:

• world-bevy MUST be listed in Cargo.toml before generating or compiling src/gen.
• Generated src/gen/world.rs code uses world_bevy::core::Context, world_bevy::core::IVariant, and world_bevy::core::IEvent — these resolve through the src/core/mod.rs re-export chain.
• Do not manually re-implement Context, Message, WorldResource, or the variant/event registration infrastructure — they are provided by world-bevy.
• The world-bevy crate already depends on bevy_app, bevy_ecs, and bevy_time; the project crate only needs a direct bevy dependency when using additional Bevy plugins not covered by world-bevy's transitive dependencies.

Step 3: Minimal runtime app (no renderer)

Before wiring systems, initialize base source files for generated modules.

src/gen/mod.rs:

pub mod world;

src/lib.rs:

pub mod r#gen;
pub mod app;

Then implement runtime entry logic.

src/main.rs example:

use bevy_app::{App, Startup, Update};
use bevy_ecs::prelude::*;
use bevy_time::{Time, TimePlugin};

#[derive(Component, Default)]
struct TickAge(f32);

fn setup(mut commands: Commands) {
    commands.spawn(TickAge::default());
}

fn tick(time: Res<Time>, mut q: Query<&mut TickAge>) {
    for mut age in &mut q {
        age.0 += time.delta_secs();
    }
}

fn main() {
    let mut app = App::new();
    app.add_plugins(TimePlugin);
    world_bevy::core::reg(&mut app);
    app.add_systems(Startup, setup);
    app.add_systems(Update, tick);
    app.run();
}

Important: world_bevy::core::reg(&mut app) must be called before any other system registration that depends on WorldResource. It inserts the WorldResource and sets up the message pump (PreUpdate) and spawn/change/despawn ordering (PostUpdate).

Step 4: Build verification

cargo check
cargo run
npm run build:wasm:node

Workflow

File Organization Rules (Mandatory)

Every graph System and EventSystem MUST follow these rules with no exceptions:

1. One file per System/EventSystem — each System or EventSystem lives in its own .rs file. Never put multiple Systems/EventSystems in the same file.
2. File naming: lowercase + underscores (snake_case) — match the graph node name converted to snake_case. Example: graph node StartGameEventSystem → file start_game_event_system.rs.
3. Directory: src/app/ — all System and EventSystem implementation files go under src/app/. Do not place them in src/gen/, src/core/, or any other directory.
4. Registration: src/app/mod.rs — every System/EventSystem module must be declared (pub mod ...) and its reg(app) called inside src/app/mod.rs. No implicit or auto-registration.
5. World startup spawn hook (mandatory): src/app/mod.rs — reg(app) MUST include app.add_systems(Startup, on_world_spawn);, and src/app/mod.rs MUST define fn on_world_spawn(mut commands: Commands) that spawns WorldContext.
6. Types & enums: src/app/types.rs — define all shared types, enums, and constants here. This includes: singleton entity IDs (e.g. const GAME_ID: &str = "game"), state enums (e.g. enum GameState { ... }), event type enums, and any constant strings used across multiple Systems/EventSystems. Do not scatter these definitions across individual System files.
7. Config definitions: src/app/config.rs — define configuration structs here. Every tunable logic parameter (speeds, durations, thresholds, sizes, probabilities) must live in a config struct, never as a hardcoded magic number in System logic. Example: struct GameConfig { pub move_speed: f32, pub jump_force: f32 }.
8. Shared helper functions: src/app/common.rs — all reusable helper functions shared by multiple Systems/EventSystems MUST be implemented in src/app/common.rs. Do not duplicate common logic across System files.
9. Config instances: src/config/*.rs + src/config/mod.rs — concrete config values go under src/config/ as separate files, split by domain (e.g. one file per map/scene: src/config/map_city.rs, src/config/map_dungeon.rs). src/config/mod.rs aggregates all config modules (pub mod map_city; pub mod map_dungeon; ...) and optionally re-exports them. Systems read config via Bevy Resource, never by importing config files directly — this keeps Systems testable with different configs.

Directory layout example:

src/
  app/
    mod.rs                       # declares all modules + calls reg(app) for each
    types.rs                     # shared types, enums, constants (rule 6)
    config.rs                    # config struct definitions (rule 7)
    common.rs                    # shared helper functions (rule 8)
    world_bootstrap_system.rs    # System: WorldBootstrapSystem
    game_system.rs               # System: GameSystem
    scene_system.rs              # System: SceneSystem (if needed)
    start_game_event_system.rs   # EventSystem: StartGameEventSystem
  config/
    mod.rs                    # aggregates all config modules
    game_config.rs            # global gameplay params
    map_city.rs               # city map config
    map_dungeon.rs            # dungeon map config
  gen/
    mod.rs
    world.rs                     # generated — never edit
  core/
    mod.rs                     # re-exports world_bevy::core::* + project-local helpers (WorldLogEvent, etc.)
  lib.rs
  main.rs

When adding a new System/EventSystem:

1. Create src/app/<snake_case_name>.rs
2. Add pub mod <snake_case_name>; to src/app/mod.rs
3. Add <snake_case_name>::reg(app); inside the reg() function in src/app/mod.rs

Ordering rule: Before implementing any System or EventSystem logic, src/app/types.rs, src/app/config.rs, and src/app/common.rs must be fully defined first. Systems consume shared types, config, and helper functions; never write System logic against missing shared modules. The correct workflow order is: types → config → common → systems.

Step 1: Sync Graph Output Into Rust

1. Confirm Graph changes are complete and validated in graph-world.
2. Regenerate src/gen if Graph changed.
3. Re-read generated src/gen/*.rs before implementing runtime logic.

Completion checks:

• Generated Context, Variant, and Event types match the current graph.
• No src/app code is written against stale generated APIs.

Step 2: Implement Systems In src/app/

Implement concrete lifecycle System behavior under src/app/ after Graph ownership is finalized.

Prerequisite: src/app/types.rs, src/app/config.rs, and src/app/common.rs must be fully defined before writing any System logic (see Ordering rule).

Follow the File Organization Rules strictly. Each graph System gets its own file in src/app/, named in snake_case, and registered in src/app/mod.rs.

Reference implementation for this skill lives in:

• skills/graph-world-bevy/src/app/
• structure aligned with /Volumes/SSD_1T/src/abpilot-cc/RPG-Platformer/src/app

Lifecycle systems in Bevy should be wired with observers and ECS queries, not by editing src/gen.

use world_bevy::core::Context;
use crate::r#gen::world::*;
use bevy_app::prelude::*;
use bevy_ecs::prelude::*;
use bevy_time::{Time, Virtual};

pub fn reg(app: &mut App) {
    app.add_systems(Update, on_update_system);
    app.add_observer(on_spawn_system);
    app.add_observer(on_despawn_system);
}

fn on_update_system(
    mut query: Query<(&Context, &mut GameTimeComponent), With<GameContext>>,
    time: Res<Time<Virtual>>,
) {
    for (_context, mut game_time) in &mut query {
        game_time.0 += time.delta_secs_f64();
    }
}

fn on_spawn_system(query: Query<(Entity, &Context), Added<GameContext>>) {
    for (_entity, _context) in &query {
        // TODO system-specific spawn logic
    }
}

fn on_despawn_system(removed: RemovedComponents<GameContext>) {
    for _entity in removed.read() {
        // TODO system-specific cleanup logic
    }
}

Implementation guidance:

• Put each graph System into its own Rust module under src/app/.
• Use snake_case file names for Rust modules and keep them aligned with graph names.
• Example: graph node GameSystem -> src/app/game_system.rs.
• Register per-system observers from pub fn reg(app: &mut App).
• Use Added<YourContext> for spawn semantics.
• Use RemovedComponents<YourContext> for despawn semantics.
• Prohibited: never use EventReader<T> or EventWriter<T>. Handle events exclusively with On<T> triggers + app.add_observer(...).
• Use Res<Time<Virtual>> for deterministic update timing.
• For simulator-visible runtime logs, emit world_bevy::core::WorldLogEvent via Commands:

commands.trigger(world_bevy::core::WorldLogEvent {
  log: "World context added".to_string(),
});

• This event-based logging is the canonical way to produce records visible from GET /api/world/log; do not rely on println! for simulator log verification.
• Query generated variant components directly; do not mirror generated state into ad-hoc global caches.
• Keep temporary working data local to the observer function or a dedicated Bevy Resource owned by runtime code.
• Do not modify generated files under src/gen.

Completion checks:

• Implemented System modules compile against the current generated Rust types.
• System logic remains in src/app/ and does not leak into src/gen/.
• After System changes, run npm run build:wasm:node.

Step 3: Implement World Startup Entry

Goal: define a deterministic startup entry that bootstraps required root/domain contexts.

You must implement startup initialization in a dedicated bootstrap module under src/app/.

use world_bevy::core::Context;
use crate::r#gen::world::*;
use bevy_app::prelude::*;
use bevy_ecs::prelude::*;

const GAME_ID: &str = "game";
const SCENE_ID: &str = "scene";

pub fn reg(app: &mut App) {
    app.add_observer(on_world_spawn_system);
}

fn on_world_spawn_system(
    query: Query<&Context, (With<WorldContext>, Added<WorldContext>)>,
    existing_game: Query<&Context, With<GameContext>>,
    existing_scene: Query<&Context, With<SceneContext>>,
    mut commands: Commands,
) {
    for world in &query {
        let has_game = existing_game.iter().any(|ctx| ctx.id == GAME_ID);
        if !has_game {
            GameContext::spawn(
                &mut commands,
                Some(world.id.clone()),
                GAME_ID,
                GameTimeComponent(0.0),
                GameStateComponent(0),
            );
        }

        let has_scene = existing_scene.iter().any(|ctx| ctx.id == SCENE_ID);
        if !has_scene {
            SceneContext::spawn(
                &mut commands,
                Some(world.id.clone()),
                SCENE_ID,
                SceneGridComponent(SceneGridSchema {
                    width: 0,
                    height: 0,
                    tile_size: 1.0,
                    tiles: Vec::new(),
                }),
            );
        }
    }
}

Startup guidance:

• Create a bootstrap System under World in graph design.
• Register its module in src/app/mod.rs.
• Use generated Context::spawn(...) helpers from src/gen.
• Keep initialization idempotent by checking existing singleton ids before spawning.
• Prefer fixed ids for singleton/root contexts.
• Use pid to attach child contexts to the owning parent context id.
• Do not resolve singleton contexts by positional child order.

Step 4: Implement EventSystems In src/app/

Implement graph EventSystem handlers as Bevy observers over generated events.

Prerequisite: src/app/types.rs, src/app/config.rs, and src/app/common.rs must be fully defined first (see Ordering rule).

Follow the File Organization Rules strictly. Each EventSystem gets its own file in src/app/, named in snake_case (e.g. StartGameEventSystem → start_game_event_system.rs), and registered in src/app/mod.rs.

use world_bevy::core::Context;
use crate::r#gen::world::*;
use bevy_app::prelude::*;
use bevy_ecs::prelude::*;

pub fn reg(app: &mut App) {
    app.add_observer(on_start_game_event_system);
}

fn on_start_game_event_system(
    trigger: On<StartGameEvent>,
    mut query: Query<(&Context, &mut GameStateComponent), With<GameContext>>,
) {
    let event = trigger.event();

    for (_context, mut game_state) in &mut query {
        game_state.0 = match event.game_type.as_str() {
            "running" => 1,
            "paused" => 2,
            _ => 0,
        };
    }
}

Implementation guidance:

• Put each graph EventSystem into its own Rust module under src/app/.
• Example: graph node StartGameEventSystem -> src/app/start_game_system.rs.
• Prohibited: NEVER use EventReader<T> or EventWriter<T> to read/write events. Use On<T> with app.add_observer(...) as the only event handling mechanism.
• Register event handlers with app.add_observer(...).
• Use On<GeneratedEvent> as the trigger type.
• Read payload from trigger.event().
• If the handler needs to expose runtime behavior to simulator logs, call commands.trigger(world_bevy::core::WorldLogEvent { ... }) in the handler path you want to verify.
• Fetch target contexts/components via ECS Query; mutate only the scope owned by the graph.
• If event payload schema changes in Graph, regenerate src/gen first, then update handler signatures.
• Do not invent new topology in runtime code to compensate for missing graph nodes; go back to graph-world.

Completion checks:

• Implemented EventSystem modules compile against the current generated event payloads.
• Event handlers only mutate graph-owned scope and stay under src/app/.
• After EventSystem changes, run npm run build:wasm.

Step 5: Register Runtime Wiring In src/app/mod.rs

After implementing handlers, wire the runtime explicitly in src/app/mod.rs.

use bevy_app::prelude::*;

pub mod config;
pub mod game_system;
pub mod start_game_system;
pub mod types;
pub mod world_bootstrap_system;

pub fn reg(app: &mut App) {
    world_bootstrap_system::reg(app);
    game_system::reg(app);
    start_game_system::reg(app);
}

Registration guidance:

• Declare pub mod types;, pub mod config;, and pub mod common; in src/app/mod.rs.
• Register every implemented System module in src/app/mod.rs.
• Register every implemented EventSystem module in src/app/mod.rs.
• Insert concrete config instances (from src/config/) as Bevy Resource in main.rs, not inside src/app/mod.rs.
• Keep src/lib.rs or src/main.rs responsible only for high-level runtime assembly:

use bevy_app::prelude::*;
use bevy_time::TimePlugin;

mod config;

fn main() {
    let mut app = App::new();
    app.add_plugins(TimePlugin);
    // Register world-bevy core infrastructure (WorldResource, message pump, spawn/change/despawn systems)
    world_bevy::core::reg(&mut app);
    // Insert concrete config instances as Resources (rule 7)
    app.insert_resource(config::game_config::GAME_CONFIG);
    world_bevy::core::reg(&mut app);
    crate::r#gen::world::reg(&mut app);
    crate::app::reg(&mut app);
    app.run();
}

Completion checks:

• Every implemented System and EventSystem module is registered.
• src/app/mod.rs matches current graph contracts.
• Runtime assembly does not require edits inside src/gen.
• After runtime wiring changes, run npm run build:wasm.

Step 5: wasm-pack packaging

1. Install wasm target and wasm-pack:

rustup target add wasm32-unknown-unknown
cargo install wasm-pack

2. Ensure root Cargo.toml exposes cdylib:

[lib]
crate-type = ["cdylib", "rlib"]

3. Build/package with npm scripts:

npm run build:wasm
# or
npm run build:wasm:bundler
npm run build:wasm:node

4. Optional direct command:

wasm-pack build . --target web --release --out-dir pkg

Completion checks:

• Runtime compiles and runs.
• ECS systems execute.
• Time resource updates normally.
• No Bevy render/window/UI modules are linked.
• pkg/ contains wasm-pack artifacts (.wasm, JS glue, package metadata).

Step 6: Cross-compile setup on macOS

1. Install Rust targets:

rustup target add \
  aarch64-apple-ios \
  x86_64-apple-ios \
  aarch64-apple-ios-sim \
  armv7-linux-androideabi \
  aarch64-linux-android \
  x86_64-apple-darwin \
  aarch64-apple-darwin \
  x86_64-pc-windows-gnu \
  x86_64-unknown-linux-gnu

2. Install cross-compile helpers:

brew install zig
cargo install cargo-zigbuild
cargo install cargo-ndk

3. Configure Android NDK (required by cargo ndk):

export ANDROID_NDK_HOME=/path/to/android-ndk
export ANDROID_NDK_ROOT="$ANDROID_NDK_HOME"

4. Run platform builds:

# iOS
npm run build:ios:arm64
npm run build:ios:x86_64
npm run build:ios:arm64_sim

# Android
npm run build:android:armv7
npm run build:android:arm64

# macOS
npm run build:macos:x86_64
npm run build:macos:arm64

# Windows / Linux (cross on macOS via zig)
npm run build:windows:x86_64
npm run build:linux:x86_64

Output notes:

• Rust artifacts are generated under target/<triple>/release/.
• Android cargo ndk outputs ABI-specific artifacts for armeabi-v7a and arm64-v8a.
• For iOS universal libs, combine device/simulator outputs later with Xcode tooling as needed.

GraphOS Integration Notes for Rust Runtime

• Keep graph topology/design operations in graph-world workflow.
• Keep runtime implementation in Rust under this skill.
• If Graph model changes, apply Graph changes first, then update Rust side adapters/systems.
• Do not introduce TypeScript runtime code in this workflow.
• Implement manual runtime logic under src/app/; keep generated code isolated under src/gen/.
• Use the reference modules in skills/graph-world-bevy/src/app/ as the baseline pattern for System/EventSystem wiring.

Quality Gates

1. Graph-first gate: runtime coding starts only after graph closure validation passes.
2. No-TS gate: no TypeScript runtime implementation is introduced.
3. Headless-Bevy gate: no rendering/window/UI Bevy modules enabled; world-bevy dependency is present in Cargo.toml.
4. Minimal-runtime gate: app, ecs, time capabilities are present and verified; world_bevy::core::reg(&mut app) is called in main.rs.
5. Generated-code gate: src/gen has been regenerated and re-read after Graph changes.
6. App-wiring gate: all manual runtime logic lives in src/app/, not src/gen/; each System/EventSystem is in its own file with snake_case naming.
7. Registration gate: every System/EventSystem module is wired through src/app/mod.rs.
8. Event-observer gate: EventReader<T> and EventWriter<T> are prohibited. All event handling MUST use On<T> triggers registered via app.add_observer(...). No Events<T> resource reads/writes anywhere in the codebase.
9. Types gate: shared types, enums, constants, and singleton IDs are centralized in src/app/types.rs; not scattered across System files.
10. Common gate: reusable helper logic is centralized in src/app/common.rs; duplicated helper implementations across System/EventSystem files are prohibited.
11. Config gate: all tunable logic parameters live in config structs (src/app/config.rs); no magic numbers in System logic; concrete config instances exist under src/config/.
12. Startup gate: world bootstrap logic is idempotent and singleton-safe.
13. Build gate: cargo check succeeds for the Rust runtime crate.
14. wasm wiring gate: after any System / EventSystem / src/app/mod.rs change, npm run build:wasm succeeds.
15. wasm gate: wasm-pack build succeeds and outputs package files.
16. cross-compile gate: all required target scripts complete successfully on macOS toolchain.

Failure Recovery

• world_bevy::core::Context or world_bevy::core::IVariant not found: ensure src/core/mod.rs contains pub use world_bevy::core::*; and Cargo.toml lists world-bevy as a dependency.
• world_bevy::core::reg not called: WorldResource will be missing, causing spawn/change/despawn systems to panic. Always call world_bevy::core::reg(&mut app) in main.rs before any system that queries Res<WorldResource>.
• cargo add bevy --no-default-features ... fails due to feature changes: use split crates bevy_app, bevy_ecs, bevy_time instead.
• Generated Rust types do not match expected Context/Event names: regenerate src/gen first, then reopen the generated files before editing src/app.
• Runtime logic was added into generated files: move that code into src/app/ modules and keep src/gen generated-only.
• System or EventSystem edits compile in native Rust but fail in wasm packaging: run npm run build:wasm:node, fix target-specific issues, and do not treat the work as complete until wasm packaging passes.
• Singleton bootstrap creates duplicates: add fixed-id existence checks before calling generated Context::spawn(...).
• Event handler needs data that is not present in the graph payload or contexts: stop Rust patching and return to graph-world to fix topology/schema first.
• Runtime compiles but time is not advancing: verify TimePlugin is added and systems run on Update schedule.
• Rendering-related crate unexpectedly appears: remove it and re-check Cargo.toml features/dependencies.
• wasm-pack build fails due to missing wasm target: run rustup target add wasm32-unknown-unknown and retry.
• wasm-pack build fails because crate type is not compatible: add [lib] crate-type = ["cdylib", "rlib"] to root Cargo.toml.
• Android build fails with NDK not found: set ANDROID_NDK_HOME and ANDROID_NDK_ROOT, then rerun cargo ndk scripts.
• Windows/Linux cross compile fails on macOS linker: install zig and use cargo zigbuild scripts (do not use plain cargo build for those targets).
• iOS build fails due to missing target: run rustup target add <ios-target> and retry.
• Request needs graph topology change: pause Rust edits and switch back to graph-world first.
• EventReader<T> or EventWriter<T> found in code: replace with On<T> trigger + app.add_observer(...). EventReader/EventWriter are legacy patterns incompatible with the observer-based event dispatch used by world-bevy.

Simulator Log Verification Loop

When implementing or fixing Systems/EventSystems, use the simulator API to verify runtime behavior in a tight iteration loop without restarting the GraphOS service.

Verification flow: pause → inspect logs

When the simulator is running and you need to check runtime behavior:

1. Pause the simulator to freeze state at the current tick:
   • POST /api/world/pause — stops the clock, preserving all runtime state and accumulated logs.
2. Inspect logs via GET /api/world/log to verify expected event, get, set, add, and del records were produced up to the pause point.
3. Analyze the log entries against expected behavior. For each log entry, check:
   • Does the operation type (event/get/set/add/del) match what the System/EventSystem should produce?
   • Do the target entity/component IDs and values match expectations?
   • Is the ordering of operations correct relative to system execution order?
4. If logs are correct, POST /api/world/resume to continue. If incorrect, proceed to the fix cycle below.

Why pause first: pausing before log inspection ensures you're reading a stable snapshot at a known point in time, rather than chasing logs that are still being written. This is especially important for systems with fast tick rates or async event flows.

Fix cycle: code change → reset → start

When logs show incorrect or missing behavior, apply the fix and restart the simulator without restarting the service:

1. Modify code — edit the Rust System/EventSystem code in src/app/.
2. Rebuild wasm — run npm run build:wasm:node to compile changes. The simulator picks up the new wasm automatically on next reset.
3. Reset — POST /api/world/reset clears all runtime state, entities, and accumulated logs, returning the simulator to initial state.
4. Start — POST /api/world/start starts the simulator clock from time zero, re-running bootstrap systems and initializing fresh state with the updated wasm.
5. Drive scenario — send events through POST /api/world/event to trigger the specific code path being verified (e.g. { "type": "MyEvent", "payload": { ... } }).
6. Pause and inspect — POST /api/world/pause then GET /api/world/log to verify the fix.
7. If logs still show incorrect behavior, return to step 1 and repeat.

Why reset-then-start (not just resume): after a code change, the old runtime state, entities, and component values may be incompatible with the updated wasm logic. Reset ensures a clean slate; start re-runs all bootstrap/Startup systems with the new code so you're testing against fresh, consistent state. Skipping reset can produce false positives or crashes from stale entity data.

API reference (from graph-world skill)

Key constraints

• Do not use cargo run for simulation log verification. cargo run launches a native binary that does not integrate with the GraphOS simulator API (/api/world/*). All log verification must go through the simulator API via npm run build:wasm:node + HTTP endpoints.
• Logs that must appear in /api/world/log should be emitted from runtime code with commands.trigger(world_bevy::core::WorldLogEvent { log: ... }); stdout logging is not a substitute for simulator records.
• Do not use the skill reference implementation's wasm for simulation. The simulator runs the project's own wasm built from the current workspace; verify via the project's npm run build:wasm:node, not by running the skill's src/app/ reference code directly.
• Never restart the GraphOS service to pick up wasm changes; npm run build:wasm:node + POST /api/world/reset then POST /api/world/start is sufficient.
• After npm run build:wasm:node succeeds, immediately verify through the simulator API before declaring the fix complete.
• If the log payload is large, generate a focused analysis script rather than reading the full response manually (see graph-world skill for /api/world/log query patterns).
• Always pause before log inspection when the simulator is running; never read logs on a running simulator — the log tail may be incomplete or still being written.

Example Requests

• Bootstrap a GraphOS world project for Rust runtime with no TypeScript runtime code.
• Initialize a Bevy headless app using only app/ecs/time and add a basic tick system in src/app/game_system.rs.
• Implement WorldBootstrapSystem and register it in src/app/mod.rs.
• Implement a generated StartGame EventSystem in src/app/start_game_system.rs.
• Migrate existing world runtime from TS to Rust + Bevy ECS/time while keeping graph workflow unchanged.