Flutter PerformanceSAFE

A collection of Agent Skills Standard and Best Practice for Programming Languages, Frameworks that help our AI Agent follow best practies on frameworks and programming laguages

The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: flutter-performance
description: Optimize Flutter widget rebuilds, memory usage, rendering, and scrolling performance. Use when diagnosing jank, reducing rebuilds, or improving list performance—not performance tests, monitoring setup, or API optimization.
metadata:
  triggers:
    files:
    - 'lib/presentation/**'
    - 'pubspec.yaml'
    - 'ListView.builder'
    keywords:
    - const
    - buildWhen
    - Isolate
    - RepaintBoundary
---
# Performance

## **Priority: P1 (HIGH)**


- **Rebuilds**: Use `const` widgets and `buildWhen` / `select` for granular updates.
- **Lists**: Always use `ListView.builder` for item recycling.
- **Heavy Tasks**: Use `compute()` or `Isolates` for parsing/logic.
- **Repaints**: Use `RepaintBoundary` for complex animations. Use `debugRepaintRainbowEnabled` to debug.
- **Images**: Use `CachedNetworkImage` + `memCacheWidth`. `precachePicture` for SVGs.
- **Keys**: Provide `ValueKey` for list items and stable IDs for reconciliation.
- **Resource Cleanup**: Dispose controllers/streams in `dispose()`.
- **Pagination**: Default to 20 items per page for network lists.
- **Build Purity**: Keep `build` methods free of heavy work; move logic to BLoC/Application.
- **Image Resizing**: Always set `maxWidth`/`maxHeight` when loading images.

## Anti-Patterns

- **No Root `setState()`**: Use `BlocBuilder` with `buildWhen` or `context.select()` for granular updates
- **No Heavy Business in `build()`**: Move sorting/filtering/heavy logic to BLoC or `compute()`
- **No Non-`const` Leaf Nodes**: Apply `const` to all static widgets to skip unnecessary reconciliation
- **No Large `Column` Lists**: Use `ListView.builder` for efficient item recycling in large lists

```dart
BlocBuilder<UserBloc, UserState>(
  buildWhen: (p, c) => p.id != c.id,
  builder: (context, state) => Text(state.name),
)
```

SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.

What the source does

Filesystem

none-observed

Network

none-observed

Shell

none-observed

Dependencies

pinned

Secrets in source

none-found

Findings (0)

No findings outside the package's declared scope.

Gates applied: no_behavioural_pass.