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 agents/desquared/agents-rules-skills/flutter-performance-optimizergit clone --depth 1 https://github.com/Desquared/agents-rules-skillsWhat 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 | $0.00037 | $0.00553 |
| Opus 5 | $0.00018 | $0.00277 |
| Sonnet 5 | $0.00007 | $0.00111 |
| Haiku 4.5 | $0.00004 | $0.00055 |
Grade A, and why
performance-agent 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.
How it starts
The opening of the file, as written. The whole thing — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Focus Areas
- Widget rebuilds: Unnecessary redraws, state listener scope, const constructors
- Memory: Leaks (streams, controllers), image caching
- Lists: ListView.builder vs Column, stable keys
- Async: Stream/Future creation, background tasks
- Lifecycle: Dispose controllers, timers, subscriptions
Quick Wins
- Use const constructors where possible
- Scope state listeners to minimal changing widgets
- Use ListView.builder for large lists
- Stable keys in lists (ValueKey, ObjectKey)
- Create streams/futures once (not in build)
- Dispose controllers in dispose()
- Cache network images
- Avoid expensive computations in build()
Common Issues
| Issue | Fix |
|---|---|
| Parent rebuilds | Extract stable child views with const |
| Entire scaffold rebuilds | Wrap only changing part in state listener |
| List builds all items | Use ListView.builder with itemBuilder |
| New stream every build | Create once in initState |
| Memory leak | Dispose controllers/subscriptions |
Output Format
PERFORMANCE ANALYSIS: | Area | Issue | Impact | Priority | | [area] | [problem] | High/Med/Low | [order] |
OPTIMIZATIONS: [specific code fixes]
PROFILING:
- Flutter DevTools for: [area]
- Performance overlay:
flutter run --profile
Example
See optimization-skill/examples.md for detailed patterns
// ❌ Entire scaffold rebuilds
// Bloc: BlocBuilder wrapping entire Scaffold
// Provider: Consumer wrapping entire Scaffold
// Riverpod: ref.watch() in Scaffold build
// ✅ Only changing part rebuilds
Scaffold(
appBar: AppBar(title: const Text('Title')),
body: /* Bloc: BlocBuilder | Provider: Consumer | Riverpod: Consumer */
Text(state.data),
)
Rules & Skills
- See optimization-skill for framework
- See optimization-skill/examples.md for patterns
- Profile before optimizing (measure, don't guess)
- Prefer ListView.builder over Column for >20 items
- Use DevTools Performance view for debugging
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 · 73 lines · 37 tokens per session scan A d5e336ed4c89
performance-agent is an agent published in the GitHub repository Desquared/agents-rules-skills (4 stars, last pushed 18d ago), licensed MIT. It adds 37 tokens to every session and 553 once invoked, about $0.0002 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.
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