frontend-flutter

A set of instructions for building Flutter mobile interfaces. Flutter is a toolkit for making apps for platforms such as iOS and Android from one codebase.

In plain words
What is it for?
Use it for Flutter screens, onboarding flows, and other interfaces using Material 3 or iOS-style Cupertino patterns.
Why use it?
It helps an agent design mobile screens using the project's Flutter version, existing widgets, and platform conventions.

Skill for Claude CodeCodex

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 skills/devdannnny/chisel/flutter
Any agent
npx skills add Devdannnny/chisel --skill flutter
Clone the repo
git clone --depth 1 https://github.com/Devdannnny/chisel

Made for: Claude Code, Codex.

Per session 145 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,131 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 $0.00145 $0.02131
Opus 5 $0.00072 $0.01066
Sonnet 5 $0.00029 $0.00426
Haiku 4.5 $0.00015 $0.00213

Measured yesterday against content hash 882cf96c5e5a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

frontend-flutter 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 yesterday.

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.

skills/frontend/flutter/SKILL.md · 208 lines

How it starts

The opening of the file, as written. The whole thing — 208 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Frontend — Flutter

Production-grade, distinctive Flutter UI. Opinionated, brand-correct, platform-aware. Built on the Prompt Architecture Standard (PAS) and the canonical design language at ../shared-rules.md, adapted for Flutter's widget model, Material 3 / Cupertino conventions, and mobile-first constraints.

Pre-flight (run BEFORE writing any code)

  1. READ ../shared-rules.md FIRST. Canonical design language.
  2. Check for screenshots/ in the codebase root. Use as design references.
  3. Confirm questionnaire.md is answered. Walk through it if not.
  4. Identify the platform target. iOS-only, Android-only, both, web, desktop. Affects design system choice (Material 3 vs Cupertino vs adaptive).
  5. Identify existing design system. If the project has ThemeData, ThemeExtensions, or custom widgets, preserve them.
  6. Check Flutter SDK version. Generate idiomatic code for the version in pubspec.yaml (Material 3 default since Flutter 3.22).

Role

You are a senior Flutter engineer with strong mobile design taste. You understand the difference between Material 3 and Cupertino, you reach for ThemeExtensions instead of hardcoded colors, you write composable widgets, and you know when ImplicitlyAnimatedWidget is enough vs. when to reach for an AnimationController.

Objective

Produce Flutter UI that passes every litmus check in ../shared-rules.md — visually distinctive, brand-correct, platform-appropriate, performant, impossible to mistake for a stock starter app — on the first generation.

Quick reference (full rules in ../shared-rules.md)

Memory aid only. Apply ALL rules from shared-rules.md:

  • One composition. Brand first. Brand test.
  • Distinctive fonts via google_fonts — NOT Roboto, NOT SF Pro defaults, and NOT Inter (it's the new AI default; avoid).
  • No flat scaffolds. ColorScheme.fromSeed with a non-default seed. ThemeExtensions for brand-specific colors.
  • Hero budget on splash/landing: brand + headline + line + CTA. App home screens are different — primary task is the hero.
  • Default: no Card. Cards only when tappable / dismissable / meaningfully elevated.
  • 2–3 intentional motions (Hero, staggered entrance, scroll-linked).
  • Real visual anchor. No abstract gradient blobs.
  • Both light and dark ColorSchemes polished.
  • SafeArea always.

Read the full file on GitHub · 208 lines

Files

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.

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. yesterday First seen · 208 lines · 145 tokens per session scan A 882cf96c5e5a

Subscribe to this mod's changes

frontend-flutter is a skill published in the GitHub repository Devdannnny/chisel (3 stars, last pushed 2mo ago), licensed MIT. It adds 145 tokens to every session and 2,131 once invoked, about $0.0007 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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