# Bevy Debugging Profiling

Bevy ECS skill for logs and diagnostics.

- Repository: https://github.com/thedivergentai/Game-Dev-Agentic-Skills (917 stars)
- Category: Engineering
- License: LGPL-3.0
- Last updated: 2026-10-16
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add thedivergentai/Game-Dev-Agentic-Skills --skill bevy-debugging-profiling -g -a claude-code -y`
Codex: `npx skills add thedivergentai/Game-Dev-Agentic-Skills --skill bevy-debugging-profiling -g -a codex -y`
Cursor: `npx skills add thedivergentai/Game-Dev-Agentic-Skills --skill bevy-debugging-profiling -g -a cursor -y`
Gemini CLI: `npx skills add thedivergentai/Game-Dev-Agentic-Skills --skill bevy-debugging-profiling -g -a gemini-cli -y`

## Description

Bevy ECS skill for logs and diagnostics. Keywords: Bevy, LogPlugin, DiagnosticsPlugin, FrameTimeDiagnosticsPlugin.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Bevy debugging and profiling

## When to use

Load this when a running app should print logs or record frame time, entity count, or process CPU and memory.

## ECS shape

- **Logs:** `LogPlugin` is part of `DefaultPlugins`. Override it with `DefaultPlugins.set(LogPlugin { level, filter, .. })`. The page's example uses `Level::DEBUG` and a filter string such as `wgpu=error,bevy_render=info,bevy_ecs=trace`. The same filter works as `RUST_LOG`. To bring your own collector, disable this plugin on `DefaultPlugins`.
- **Diagnostics core:** `DiagnosticsPlugin` adds the core resources. `DiagnosticsStore` holds the collection. `Diagnostic` is a timeline of `DiagnosticMeasurement` values addressed by `DiagnosticPath`. `RegisterDiagnostic` adds `register_diagnostic` on `App`.
- **Built-in plugins:** `FrameTimeDiagnosticsPlugin` adds frame time, fps, and frame count. `EntityCountDiagnosticsPlugin` adds an entity count. `SystemInformationDiagnosticsPlugin` adds `cpu_usage` and `mem_usage` percent. `LogDiagnosticsPlugin` prints diagnostics to the console. `FrameCount` / `FrameCountPlugin` count frames since start.
- **Order:** the log-diagnostics example adds these plugins after `DefaultPlugins` because they use the time plugin for timestamps.
- **Schedule:** built-in plugins measure on their own. Read `DiagnosticsStore` when a HUD needs the latest sample. Register a `Diagnostic` only for a value you measure yourself.

## Examples

```toml
[dependencies]
bevy = "0.20"
```

`LogPlugin` ships inside `DefaultPlugins`. Replace its level and filter when the default `info` stream is too quiet or too loud.

```rust
use bevy::log::{Level, LogPlugin};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins.set(LogPlugin {
            filter: "wgpu=error,bevy_render=info,bevy_ecs=trace".into(),
            level: Level::DEBUG,
            ..default()
        }))
        .run();
}
```

The rest: https://github.com/thedivergentai/Game-Dev-Agentic-Skills/blob/HEAD/skills/bevy-debugging-profiling/SKILL.md