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 skills add jxoesneon/Ciel --skill flutter-developmentgit clone --depth 1 https://github.com/jxoesneon/CielWrote 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/jxoesneon/ciel/flutter-development)<a href="https://agentmods.dev/skills/jxoesneon/ciel/flutter-development"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/flutter-development/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/jxoesneon/ciel/flutter-development"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/flutter-development.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00018 | $0.00416 |
| Opus 5.5 | $0.00007 | $0.00166 |
| Sonnet 5.5 | $0.00004 | $0.00083 |
| Haiku 4.5 | $0.00002 | $0.00042 |
Grade A, and why
flutter-development 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 1mo 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
CIEL ADAPTATION: Flutter Development (Patterns & Review)
This skill formalizes the development and review of Flutter/Dart applications. It combines idiomatic implementation patterns with a rigorous quality checklist.
Implementation Standards
- Null Safety: Avoid
!. Prefer?.,??, or Dart 3 pattern matching (switch (user) { ... }). - Immutability: Use sealed classes for state hierarchies and
freezedfor boilerplate-freecopyWith. - Widget Purity: Extract sub-widgets to Classes, NOT private methods (enables
constpropagation and element reuse). - Reactivity: check
mountedafter everyawaitbefore usingBuildContext.
State Management Decision Matrix
- Simple/Atomic:
ValueNotifierorProvider. - Complex/Async:
BLoC/Cubit(Event-driven) orRiverpod(Functional/Derived). - Hard Gate: Never store
BuildContextin a state manager or singleton.
Quality Checklist (The Auditor Gate)
- No
print()in production; uselog(). - Widgets under 100 lines.
- Colors/Fonts from
Theme.of(context), never hardcoded hex. -
constconstructors used at every possible boundary.
Anti-Patterns
- Boolean Flag Soup: Using
isLoading,isErrorflags instead of a sealedAsyncStatetype. - Deep Nesting: Nesting more than 5 levels of widgets (Extract to sub-classes).
- Bang-Operator Abuse: Using
!to "fix" nullability errors instead of proper guarding.
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.
- 1mo ago Changed · -13 lines dbe64ea35040
- 1mo ago First seen · 52 lines · 18 tokens per session scan A 307087e4a0d2
flutter-development is a skill published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed 4d ago), licensed Apache-2.0. It adds 18 tokens to every session and 416 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-03.
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