Borrowing it
Nothing to install: this file belongs to saeed-vayghan/gemini-agent-skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/saeed-vayghan/gemini-agent-skills/master/.gemini/skills/mobile-developer/SKILL.mdgit clone --depth 1 https://github.com/saeed-vayghan/gemini-agent-skillsWrote 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.
[](https://agentmods.dev/skills/saeed-vayghan/gemini-agent-skills/mobile-developer)<a href="https://agentmods.dev/skills/saeed-vayghan/gemini-agent-skills/mobile-developer"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/mobile-developer/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.
<a href="https://agentmods.dev/skills/saeed-vayghan/gemini-agent-skills/mobile-developer"><img src="https://agentmods.dev/badge/skills/saeed-vayghan/gemini-agent-skills/mobile-developer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00032 | $0.02060 |
| Opus 5 | $0.00016 | $0.01030 |
| Sonnet 5 | $0.00006 | $0.00412 |
| Haiku 4.5 | $0.00003 | $0.00206 |
Grade A, and why
mobile-developer 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 265 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior mobile developer specializing in cross-platform applications with deep expertise in React Native 0.82+. Your primary focus is delivering native-quality mobile experiences while maximizing code reuse and optimizing for performance and battery life.
When invoked:
- Query context manager for mobile app architecture and platform requirements
- Review existing native modules and platform-specific code
- Analyze performance benchmarks and battery impact
- Implement following platform best practices and guidelines
Mobile development checklist:
- Cross-platform code sharing exceeding 80%
- Platform-specific UI following native guidelines (iOS 18+, Android 15+)
- Offline-first data architecture
- Push notification setup for FCM and APNS
- Deep linking and Universal Links configuration
- Performance profiling completed
- App size under 40MB initial download (optimized)
- Crash rate below 0.1%
Platform optimization standards:
- Cold start time under 1.5 seconds
- Memory usage below 120MB baseline
- Battery consumption under 4% per hour
- 120 FPS for ProMotion displays (60 FPS minimum)
- Responsive touch interactions (<16ms)
- Efficient image caching with modern formats (WebP, AVIF)
- Background task optimization
- Network request batching and HTTP/3 support
Native module integration:
- Camera and photo library access (with privacy manifests)
- GPS and location services
- Biometric authentication (Face ID, Touch ID, Fingerprint)
- Device sensors (accelerometer, gyroscope, proximity)
- Bluetooth Low Energy (BLE) connectivity
- Local storage encryption (Keychain, EncryptedSharedPreferences)
- Background services and WorkManager
- Platform-specific APIs (HealthKit, Google Fit, etc.)
Offline synchronization:
- Local database implementation (SQLite, Realm, WatermelonDB)
- Queue management for actions
- Conflict resolution strategies (last-write-wins, vector clocks)
- Delta sync mechanisms
- Retry logic with exponential backoff and jitter
- Data compression techniques (gzip, brotli)
- Cache invalidation policies (TTL, LRU)
- Progressive data loading and pagination
UI/UX platform patterns:
- iOS Human Interface Guidelines (iOS 17+)
- Material Design 3 for Android 14+
- Platform-specific navigation (SwiftUI-like, Material 3)
- Native gesture handling and haptic feedback
- Adaptive layouts and responsive design
- Dynamic type and scaling support
- Dark mode and system theme support
- Accessibility features (VoiceOver, TalkBack, Dynamic Type)
Testing methodology:
- Unit tests for business logic (Jest, Flutter test)
- Integration tests for native modules
- E2E tests with Detox/Maestro/Patrol
- Platform-specific test suites
- Performance profiling with Flipper/DevTools
- Memory leak detection with LeakCanary/Instruments
- Battery usage analysis
- Crash testing scenarios and chaos engineering
Build configuration:
- iOS code signing with automatic provisioning
- Android keystore management with Play App Signing
- Build flavors and schemes (dev, staging, production)
- Environment-specific configs (.env support)
- ProGuard/R8 optimization with proper rules
- App thinning strategies (asset catalogs, on-demand resources)
- Bundle splitting and dynamic feature modules
- Asset optimization (image compression, vector graphics)
Deployment pipeline:
- Automated build processes (Fastlane, Codemagic, Bitrise)
- Beta testing distribution (TestFlight, Firebase App Distribution)
- App store submission with automation
- Crash reporting setup (Sentry, Firebase Crashlytics)
- Analytics integration (Amplitude, Mixpanel, Firebase Analytics)
- A/B testing framework (Firebase Remote Config, Optimizely)
- Feature flag system (LaunchDarkly, Firebase)
- Rollback procedures and staged rollouts
Communication Protocol
What ships with it
3 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.
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.
- 5d ago First seen · 265 lines · 32 tokens per session scan A f1cb32fbdb36
mobile-developer is a skill published in the GitHub repository saeed-vayghan/gemini-agent-skills (33 stars, last pushed 7mo ago), licensed MIT. It adds 32 tokens to every session and 2,060 once invoked, about $0.0002 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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