flutter

flutter is a skill for Claude Code, Codex from ericrisco/rsc-harness. It costs 91 tokens per session (4,361 once invoked), scanned A, original, MIT.

A guide for building Flutter mobile apps with a consistent app structure, state handling, navigation, data access, and Material 3 design.

In plain words
What is it for?
It supports structuring, testing, optimizing, and troubleshooting Flutter and Dart applications, including widget and visual comparison tests.
Why use it?
It helps teams make architectural choices consistently and avoid mixing competing approaches in one app.

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/ericrisco/rsc-harness/flutter
Any agent
npx skills add ericrisco/rsc-harness --skill flutter
Clone the repo
git clone --depth 1 https://github.com/ericrisco/rsc-harness

Made for: Claude Code, Codex.

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/ericrisco/rsc-harness/flutter.svg)](https://agentmods.dev/skills/ericrisco/rsc-harness/flutter)
Your own site
<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/flutter"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/flutter.svg" alt="Measured on agentmods" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,361 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00091 $0.04361
Opus 5 $0.00046 $0.02181
Sonnet 5 $0.00018 $0.00872
Haiku 4.5 $0.00009 $0.00436

Measured yesterday against content hash 56c9ac7c7d4b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

flutter scanned grade A with 1 finding 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/verify.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

return handler.resolve(await dio.fetch(error.requestOptions));
skills/flutter/SKILL.md · 401 lines

How it starts

The opening of the file, as written. The whole thing — 401 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Flutter & Dart app architecture

The opinionated default stack for a production Flutter app: feature-first + layered folders, Riverpod 3 with codegen for shared/async state, a typed go_router, freezed immutable models, a dio data layer, and explicit Result<T, Failure> error modeling — all on Material 3. Escape hatches are first-class: Bloc/Cubit instead of Riverpod when the team already runs Bloc, and raw http/get_it are allowed — but pick one of each per app, never mix two. Pinned versions this skill targets: Flutter 3.44 / Dart 3.12, Riverpod 3.0, go_router 17.2.x (+ go_router_builder 4.3.x), freezed 3.x / json_serializable, dio 5.x, mocktail 1.x.

Boundaries

⚠️ SDD new-feature gate — read this first. If this skill fired on a new, non-trivial feature or behaviour change and there is no approved spec + plan under 02-DOCS/wiki/sdd/, STOP — do not write feature code yet. Hand off to ../specify/SKILL.md first: it runs brainstorm → spec → plan → tasks before any code, then routes back here once the plan is approved. Build here directly only for a genuinely one-line / low-risk change. Method: ../sdd/SKILL.md.

This skill owns the pubspec.yaml subproject and nothing else in the repo. Hand off when the UI is Compose Multiplatform (compose-multiplatform), SwiftUI/native iOS (swift-ios) or React Native (react-native); when the work is on a FastAPI/Go/Next.js sibling in the same monorepo (use that skill). For a pure Dart server/CLI with no widget tree, general Dart applies but skip the UI/nav/perf references. For a single-file throwaway sample, say architecture is overkill and do not impose layering.

Around the edges: harness owns the workspace 01-TOOLS/02-DOCS layer and flavor secrets; fastapi, go and nextjs build the backends this app talks to; secure-coding reviews token handling and deep-link validation; deployment handles store/CI release; design owns the Material 3 token system.

Read the full file on GitHub · 401 lines

Files

What ships with it

8 files 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 · 401 lines · 91 tokens per session scan A 56c9ac7c7d4b

Subscribe to this mod's changes

flutter is a skill published in the GitHub repository ericrisco/rsc-harness (64 stars, last pushed 2d ago), licensed MIT. It adds 91 tokens to every session and 4,361 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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