flutter-expert

A guide for building Flutter apps with Dart, where reusable widgets form interfaces that can run on mobile, web, and desktop. It also covers links to platform-specific iOS and Android features.

In plain words
What is it for?
Use it to design Flutter architecture, create widgets and adaptive screens, manage state, connect Swift or Kotlin platform features, add tests, and prepare iOS, Android, web, or desktop builds.
Why use it?
It helps choose a suitable app structure and state-management approach as a Flutter project grows. It also addresses responsive layouts, testing, performance, and differences between target platforms.

Agent for Claude Code

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/echovic/blade-code/flutter-expert
Clone the repo
git clone --depth 1 https://github.com/echoVic/blade-code

Made for: Claude Code.

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 527 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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 $0.00527
Opus 5 $0.00029 $0.00264
Sonnet 5 $0.00012 $0.00105
Haiku 4.5 $0.00006 $0.00053

Measured 2d ago against content hash 145130f73082, 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 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.

.claude/agents/flutter-expert.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 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 · 89 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. 2d ago First seen · 89 lines · 58 tokens per session scan A 145130f73082

Subscribe to this mod's changes

flutter-expert is an agent published in the GitHub repository echoVic/blade-code (177 stars, last pushed 2d ago), licensed MIT. It adds 58 tokens to every session and 527 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 2026-08-30.