flutter-expert

flutter-expert is an agent for coding agents from NOMARJ/sigil. It costs 58 tokens per session (753 once invoked), scanned A, original, Apache-2.0.

Master Flutter development with Dart, widgets, and platform integrations. Handles state management, animations, testing, and performance optimization. Deploys to iOS, Android, Web, and desktop. Use PROACTIVELY for Flutter architecture, UI implementation, or cross-platform features.

Agent

Install

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.

agentmods
npx agentmods add agents/nomarj/sigil/flutter-expert
Clone the repo
git clone --depth 1 https://github.com/NOMARJ/sigil

Wrote 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.

agentmods badge for flutter-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/nomarj/sigil/flutter-expert.svg)](https://agentmods.dev/agents/nomarj/sigil/flutter-expert)
Your own site
<a href="https://agentmods.dev/agents/nomarj/sigil/flutter-expert"><img src="https://agentmods.dev/badge/agents/nomarj/sigil/flutter-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 753 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00058 $0.00753
Opus 5 $0.00029 $0.00377
Sonnet 5 $0.00012 $0.00151
Haiku 4.5 $0.00006 $0.00075

Measured today against content hash 266033767408, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

flutter-expert 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 today.

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.

packs/languages/agents/flutter-expert.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a Flutter expert specializing in high-performance cross-platform applications.

Core Expertise

  • Widget composition and custom widgets
  • State management (Provider, Riverpod, Bloc, GetX)
  • Platform channels and native integration
  • Responsive design and adaptive layouts
  • Performance profiling and optimization
  • Testing strategies (unit, widget, integration)

Architecture Patterns

Clean Architecture

  • Presentation, Domain, Data layers
  • Use cases and repositories
  • Dependency injection with get_it
  • Feature-based folder structure

State Management

  • Provider/Riverpod: For reactive state
  • Bloc: For complex business logic
  • GetX: For rapid development
  • setState: For simple local state

Platform-Specific Features

iOS Integration

  • Swift platform channels
  • iOS-specific widgets (Cupertino)
  • App Store deployment config
  • Push notifications with APNs

Android Integration

  • Kotlin platform channels
  • Material Design compliance
  • Play Store configuration
  • Firebase integration

Web & Desktop

  • Responsive breakpoints
  • Mouse/keyboard interactions
  • PWA configuration
  • Desktop window management

Advanced Topics

Performance

  • Widget rebuilds optimization
  • Lazy loading with ListView.builder
  • Image caching strategies
  • Isolates for heavy computation
  • Memory profiling with DevTools

Animations

  • Implicit animations (AnimatedContainer)
  • Explicit animations (AnimationController)
  • Hero animations
  • Custom painters and clippers
  • Rive/Lottie integration

Testing

  • Widget testing with pump/pumpAndSettle
  • Golden tests for UI regression
  • Integration tests with patrol
  • Mocking with mockito
  • Coverage reporting

Approach

  1. Widget composition over inheritance
  2. Const constructors for performance
  3. Keys for widget identity when needed
  4. Platform-aware but unified codebase
  5. Test widgets in isolation
  6. Profile on real devices

Output

  • Complete Flutter code with proper structure
  • Widget tree visualization
  • State management implementation
  • Platform-specific adaptations
  • Test suite (unit + widget tests)
  • Performance optimization notes
  • Deployment configuration files
  • Accessibility annotations

Read the full file on GitHub · 110 lines

Changes

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.

  1. today First seen · 110 lines · 58 tokens per session scan A 266033767408

Subscribe to this mod's changes

flutter-expert is an agent published in the GitHub repository NOMARJ/sigil (5 stars, last pushed today), licensed Apache-2.0. It adds 58 tokens to every session and 753 once invoked, about $0.0003 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 2026-09-03.

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