cross-platform

cross-platform is a skill for Claude Code from MonumentalSystems/Atlas-Agent-Teams. It costs 15 tokens per session (597 once invoked), scanned A, original, MIT.

A guide to building one mobile app for multiple platforms, such as iOS and Android, with frameworks including React Native and Flutter. It covers shared code, platform-specific modules, navigation, and app structure.

In plain words
What is it for?
Use it to plan cross-platform architecture, manage shared state and navigation, integrate native features, and choose patterns for React Native or Flutter projects.
Why use it?
It helps teams share application logic while handling differences between mobile platforms.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the mobile-dev plugin — 4 skills, 1 command, 5 agents shipped together

Good fit Use it to plan cross-platform architecture, manage shared state and navigation, integrate native features, and choose patterns for React Native or Flutter projects.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/monumentalsystems/atlas-agent-teams/cross-platform
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.

Any agent
npx skills add MonumentalSystems/Atlas-Agent-Teams --skill cross-platform
Clone the repo
git clone --depth 1 https://github.com/MonumentalSystems/Atlas-Agent-Teams

Made for: Claude Code.

Or install mobile-dev, the plugin that ships this one along with the rest of its 4 skills, 1 command, 5 agents.

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 cross-platform

README.md
[![agentmods](https://agentmods.dev/badge/skills/monumentalsystems/atlas-agent-teams/cross-platform/github.svg)](https://agentmods.dev/skills/monumentalsystems/atlas-agent-teams/cross-platform)
Your own site
<a href="https://agentmods.dev/skills/monumentalsystems/atlas-agent-teams/cross-platform"><img src="https://agentmods.dev/badge/skills/monumentalsystems/atlas-agent-teams/cross-platform/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.

agentmods 80×15 button for cross-platform

Your own site · 80×15
<a href="https://agentmods.dev/skills/monumentalsystems/atlas-agent-teams/cross-platform"><img src="https://agentmods.dev/badge/skills/monumentalsystems/atlas-agent-teams/cross-platform.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 597 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00015 $0.00597
Opus 5 $0.00008 $0.00298
Sonnet 5 $0.00003 $0.00119
Haiku 4.5 $0.00002 $0.00060

Measured 6d ago against content hash 545016f6adbe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

cross-platform 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 6d 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.

teams/mobile-dev/skills/cross-platform/SKILL.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cross-Platform Development Guidelines

React Native Development

  • Use React Native 0.72+ with modern features
  • Use functional components with Hooks
  • Use TypeScript for type safety
  • Implement proper navigation with React Navigation
  • Use Redux, MobX, or Zustand for state management
  • Follow React Native best practices
  • Use Expo for rapid prototyping when appropriate

Flutter Development

  • Use Flutter 3.16+ with Dart 3.0+
  • Use StatefulWidget and StatelessWidget appropriately
  • Use Provider, Riverpod, or Bloc for state management
  • Implement proper navigation with Navigator 2.0
  • Follow Flutter best practices and widget composition
  • Use Flutter DevTools for debugging
  • Leverage pub.dev for packages

Cross-Platform Architecture Patterns

  • MVVM: Use with reactive state management
  • BLoC Pattern: Use with Flutter for business logic
  • Clean Architecture: Separate layers properly
  • Repository Pattern: Abstract data sources
  • Implement proper dependency injection
  • Separate business logic from UI code
  • Use shared code for business logic

Native Module Integration

  • Create native modules for platform-specific features
  • Use React Native Native Modules for iOS/Android
  • Use Flutter Platform Channels for native communication
  • Implement proper error handling across platforms
  • Maintain consistent APIs across platforms
  • Use platform-specific optimizations when needed
  • Document native module interfaces

Cross-Platform State Management

  • React Native: Redux, MobX, Zustand, Context API
  • Flutter: Provider, Riverpod, Bloc, GetX
  • Implement proper state persistence
  • Use immutable state patterns
  • Handle async operations properly
  • Use middleware for side effects
  • Implement proper state hydration

Cross-Platform Navigation

  • React Native: React Navigation (Stack, Tab, Drawer)
  • Flutter: Navigator 2.0, GoRouter, AutoRoute
  • Implement deep linking properly
  • Handle back button behavior correctly
  • Use type-safe navigation when possible
  • Implement proper route guards
  • Handle navigation state persistence

Read the full file on GitHub · 80 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. 6d ago First seen · 80 lines · 15 tokens per session scan A 545016f6adbe

Subscribe to this mod's changes

cross-platform is a skill published in the GitHub repository MonumentalSystems/Atlas-Agent-Teams (21 stars, last pushed 29d ago), licensed MIT. It adds 15 tokens to every session and 597 once invoked, about $0.0001 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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