Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/ofershap/flutter-best-practices/best-practicesgit clone --depth 1 https://github.com/ofershap/flutter-best-practicesWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00329 | $0.00329 |
| Opus 5 | $0.00164 | $0.00164 |
| Sonnet 5 | $0.00066 | $0.00066 |
| Haiku 4.5 | $0.00033 | $0.00033 |
Grade A, and why
best-practices scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Before generating Flutter or Dart code:
- Routing: Use GoRouter. Never use
Navigator.push,Navigator.pop, orMaterialPageRoute. Usecontext.go,context.push, and declarative route configuration. - Dart 3: If the task involves state handling, multiple variants, or grouped return values, use sealed classes with exhaustive switch and records. Do not generate long if/else chains or
Map<String, dynamic>for structured data. - State: For shared or app-level state, use Riverpod (StateNotifierProvider, AsyncNotifierProvider). Do not use setState for state shared across widgets.
- Const: Add
constto widget constructors when all arguments are compile-time constants. - Theme: Use
Theme.of(context).colorScheme,Theme.of(context).textTheme. Do not hardcode colors, font sizes, or padding. - Platform: If using
dart:io(Directory, File, Platform), add a kIsWeb check or conditional import so code does not crash on web. - Scrollables: Do not nest ListView, GridView, or SingleChildScrollView inside another scrollable. Use CustomScrollView with SliverList, SliverGrid, SliverToBoxAdapter.
- Context after async: After any
await, checkif (!context.mounted) returnbefore usingcontext(e.g. for Navigator, Theme, or routing).
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 16 lines · 329 tokens per session scan A e3b04ee52c0d
best-practices is a cursor rule published in the GitHub repository ofershap/flutter-best-practices (1 stars, last pushed 6mo ago), licensed MIT. It adds 329 tokens to every session, about $0.0016 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other cursor rules, from other repositories
flutter_ui_dev
// Header section Column( children: [ // Title Text('Title'), // Subtitle Text('Subtitle'), ], ).
flutter-app
Convenções do app Flutter (lib/).
best-practices
Expo Best Practices - enforces current best practices when working with Expo / React Native code.
create-view
Step-by-step guide to create a new MasterFabric view with State, Cubit, and MasterViewCubit.
masterfabric-conventions
MasterFabric Core conventions - MVVM+BLoC, naming, state management, DI.
platform-channels
Native iOS/Android integration via platform channels - no Dart packages, MethodChannel.