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 skills/desquared/agents-rules-skills/flutter-performance-optimizernpx skills add Desquared/agents-rules-skills --skill flutter-performance-optimizergit clone --depth 1 https://github.com/Desquared/agents-rules-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/desquared/agents-rules-skills/flutter-performance-optimizer)<a href="https://agentmods.dev/skills/desquared/agents-rules-skills/flutter-performance-optimizer"><img src="https://agentmods.dev/badge/skills/desquared/agents-rules-skills/flutter-performance-optimizer.svg" alt="Measured on agentmods" height="20"></a>What 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 | $0.00047 | $0.00423 |
| Opus 5 | $0.00023 | $0.00211 |
| Sonnet 5 | $0.00009 | $0.00085 |
| Haiku 4.5 | $0.00005 | $0.00042 |
Grade A, and why
flutter-performance-optimizer scanned grade A with 1 finding 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 3d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
// ❌ for (item in items) await api.fetch(item.id); What it actually says
Optimization Skill
Quick Wins
// 1. const: const Text('Title') vs Text('Title')
// 2. Narrow BlocBuilder: Scaffold(body: BlocBuilder(...))
// vs BlocBuilder(builder: (ctx, state) => Scaffold(...))
// 3. buildWhen: buildWhen: (prev, curr) => prev.data != curr.data
// 4. ListView.builder vs ListView(children: [])
// 5. Keys: key: ValueKey(items[i].id)
// 6. Batch API:
// ❌ for (item in items) await api.fetch(item.id);
// ✅ await Future.wait(items.map((i) => api.fetch(i.id)));
// ✅✅ await api.fetchBatch(ids);
// 7. Debounce:
Timer? _debounce;
void onSearchChanged(String q) {
_debounce?.cancel();
_debounce = Timer(Duration(milliseconds: 300), () => _search(q));
}
// 8. Heavy work: compute(_heavy, data) in Bloc, NOT in build()
// 9. Images: CachedNetworkImage with width/height
// 10. Memory leaks:
@override Future<void> close() { _controller.close(); return super.close(); }
@override void dispose() { _timer?.cancel(); super.dispose(); }
Common Issues
- BlocBuilder wraps entire screen → Narrow scope
- Missing const → Add const
- No buildWhen → Filter rebuilds
- ListView without .builder → Use .builder
- Sequential API calls → Batch or parallel
- Heavy computation in build() → Move to Bloc/isolate
- Streams/timers not closed → Dispose properly
Diagnostics
flutter run --profile --trace-skia
# DevTools → Memory, Performance
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 3d ago First seen · 57 lines · 47 tokens per session scan A 54f509407667
flutter-performance-optimizer is a skill published in the GitHub repository Desquared/agents-rules-skills (4 stars, last pushed 20d ago), licensed MIT. It adds 47 tokens to every session and 423 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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