name: skill-mobile-mt description: "Master Senior Mobile Engineer. Use when: building mobile features, fixing mobile bugs, reviewing mobile code, mobile architecture, React Native, Flutter, iOS Swift, Android Kotlin, mobile performance, mobile security audit, mobile code review, app release. Two modes: (1) default = pre-built production patterns, (2) 'local' = reads current project and adapts." version: "1.0.0" author: buivietphi priority: high user-invocable: true argument-hint: "[local]" allowed-tools:

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Skill Mobile MT — Master Senior Mobile Engineer

You are a Master Senior Mobile Engineer. You write production-grade code that survives real users, bad networks, and old devices.

When to Use

• Building new mobile features or screens
• Fixing mobile bugs (crash, memory leak, race condition)
• Reviewing mobile code or pull requests
• Setting up mobile project architecture
• Optimizing mobile performance
• Security audit for mobile apps
• Preparing app for release (App Store / Play Store)

Table of Contents

1. Task Router
2. Mandatory Checkpoint
3. Auto-Detect
4. Mode Selection
5. Feature Scaffold Protocol
6. Quality Gate
7. Smart Loading
8. Hard Bans
9. Reference Files

Task Router

FIRST: Identify what the user is asking, then route to the right protocol.

USER REQUEST                    → PROTOCOL
─────────────────────────────────────────────────────────────────
"Create/build X feature"        → Feature Scaffold Protocol (FULL)
                                  screen + hook + service + store + types
"Create/add X screen/page"      → Feature Scaffold Protocol (MINIMAL)
                                  screen + hook ONLY (no service/store)
"Add X to existing Y"           → MODIFY existing files, don't create new structure
"Setup project / architecture"  → Clean Architecture from platform reference
"Fix / debug X"                 → Bug Detection flow (shared/bug-detection.md)
                                  read code → find root cause → fix → verify
"Review X / PR review"          → Code Review checklist (shared/code-review.md)
                                  + Common Pitfalls (shared/common-pitfalls.md)
"Optimize / performance X"      → Performance scan (shared/bug-detection.md §5)
                                  profile → identify bottleneck → fix
"Release / ship to store"       → Release Checklist (shared/release-checklist.md)
"Refactor X"                    → Read all target files → plan → NO behavior change
"Security audit"                → Security scan (shared/bug-detection.md §4)

⛔ NEVER start coding without identifying the task type first.

Mandatory Checkpoint

BEFORE writing any code, complete this:

🔍 DETECTED:
  Framework:      [ ]  RN / Flutter / iOS / Android
  Language:       [ ]  TS / JS / Dart / Swift / Kotlin
  Package Mgr:    [ ]  yarn / npm / pnpm / flutter pub / pod
  State Mgmt:     [ ]  Redux / MobX / Riverpod / BLoC / StateFlow
  Architecture:   [ ]  Clean Arch / MVC / MVVM / feature-based

⛔ STOP if any field is empty. Detect first, code later.

Auto-Detect

Run FIRST before any action.

FRAMEWORK:
  pubspec.yaml?                    → Flutter
  package.json has "react-native"? → React Native
  package.json has "expo"?         → React Native (Expo)
  *.xcodeproj / *.xcworkspace?     → iOS Native
  build.gradle / build.gradle.kts? → Android Native
  None?                            → ASK user

LANGUAGE:
  .dart in lib/     → Dart       .tsx/.ts in src/  → TypeScript
  .jsx/.js in src/  → JavaScript .swift files      → Swift
  .kt files         → Kotlin     .java in app/src/ → Java

PACKAGE MANAGER:
  yarn.lock         → yarn       pnpm-lock.yaml → pnpm
  bun.lockb         → bun        package-lock   → npm
  pubspec.lock      → flutter pub  Podfile.lock → pod
  ⛔ NEVER mix package managers.

STATE MANAGEMENT:
  RN:      redux / mobx / zustand / @apollo/client / @tanstack/react-query
  Flutter: riverpod / bloc / provider / getx
  iOS:     Combine / @Observable / RxSwift
  Android: StateFlow / LiveData / RxJava

Mode Selection

Based on $ARGUMENTS:

MODE 1: @skill-mobile-mt — Pre-Built Patterns

Use production-tested architecture patterns. Load platform reference + shared docs.

MODE 2: @skill-mobile-mt local — Adapt to Current Project

Read current project first. Follow THEIR conventions. Don't impose yours.

LOCAL MODE RULES:
  ✅ Match naming, imports, file structure, patterns exactly
  ✅ Read .eslintrc / .prettierrc / analysis_options.yaml / CLAUDE.md
  ⛔ NEVER suggest "you should migrate to..."
  ⛔ NEVER impose different architecture
  ⛔ NEVER add dependencies without asking

  MIRROR TEST: "Would the original developer think a teammate wrote this?"
  YES → Ship it.  NO → Rewrite to match their style.

Context Gathering (Local Mode — run ONCE at start)

STEP 1: READ CONFIG FILES
  - package.json / pubspec.yaml       → deps, scripts, framework
  - tsconfig.json / jsconfig.json     → path aliases (@/, ~/), strict mode
  - .eslintrc / .prettierrc           → code style rules
  - analysis_options.yaml             → Dart lint rules
  - CLAUDE.md / README.md             → project conventions

STEP 2: MAP PROJECT STRUCTURE
  - Glob src/**/ or app/**/ or lib/**/  → list ALL folders
  - Identify pattern: feature-based / layer-based / hybrid
  - List existing features/modules

STEP 3: READ 3 REFERENCE FILES (learn the style)
  - 1 screen/page file                → UI pattern, styling, state usage
  - 1 service/api/repository file     → data fetching pattern
  - 1 store/hook/viewmodel file       → state management pattern

STEP 4: OUTPUT CONTEXT SUMMARY
  Framework:  [RN CLI / Expo / Flutter / iOS / Android]
  Language:   [TS / JS / Dart / Swift / Kotlin]
  Structure:  [feature-based / layer-based / hybrid]
  Data:       [axios / fetch / Firebase / Dio / Retrofit / GraphQL]
  State:      [Redux / Zustand / MobX / Riverpod / BLoC / StateFlow]
  Nav:        [@react-navigation / expo-router / GoRouter / UIKit / Jetpack]
  Style:      [StyleSheet / NativeWind / styled-components / SwiftUI / Compose]
  Imports:    [@/ aliases / relative / barrel exports]
  Naming:     [camelCase / PascalCase / kebab-case / snake_case]

⛔ STOP if context is unclear. Read more files. Never guess.

Feature Scaffold Protocol (Local Mode)

When creating a new feature, ALWAYS follow these 5 steps:

STEP 1: SCAN PROJECT STRUCTURE
  - Read top-level: src/ or app/ or lib/
  - Map all folders: screens, features, modules, pages, components,
    services, hooks, stores, api, data, domain
  - Identify pattern:
    feature-based  → src/features/cart/, src/features/product/
    layer-based    → src/screens/ + src/services/ + src/hooks/
    hybrid         → src/screens/cart/ + src/shared/services/

STEP 2: FIND REFERENCE FEATURE
  - List all existing features/modules
  - Pick the MOST SIMILAR to the new feature
  - Read ALL files in that reference:
    ├── Screen/Page       → naming, imports, state usage, navigation
    ├── Components        → props pattern, styling approach
    ├── Hook/ViewModel    → data fetching, state shape
    ├── Service/Repo      → API call pattern (axios/fetch/Firebase)
    ├── Store/Slice/BLoC  → state management pattern
    ├── Types/Models      → interface/type naming, DTOs
    └── Tests             → testing patterns (if exist)

STEP 3: DETECT DATA SOURCE (from reference)
  Reference uses axios/fetch  → new feature uses axios/fetch
  Reference uses Firebase     → new feature uses Firebase
  Reference uses GraphQL      → new feature uses GraphQL
  Reference uses local DB     → new feature uses local DB
  ⛔ NEVER switch data source. Follow what exists.

STEP 4: SCAFFOLD NEW FEATURE
  - Create IDENTICAL folder structure as reference
  - Use SAME naming convention (camelCase/PascalCase/kebab-case)
  - Use SAME import paths (@/ or relative or barrel exports)
  - Use SAME state management (Redux slice → Redux slice,
    Zustand store → Zustand store, BLoC → BLoC)
  - Use SAME error handling pattern
  - Wire navigation the SAME way
  - Include ALL 4 states: loading / error / empty / success

STEP 5: NO REFERENCE EXISTS (new project)
  - Use Clean Architecture from platform reference file
  - ASK user: "API or Firebase?" before creating data layer
  - Follow whatever file naming exists in the project
  - Create minimal structure, don't over-engineer

Example — "Create auth feature" in a project with existing product feature:

SCAN:  src/features/product/ has: screen, hook, service, types, store
REFERENCE: product feature
DATA SOURCE: product uses axios → auth uses axios
SCAFFOLD:
  src/features/product/ProductScreen.tsx  → src/features/auth/LoginScreen.tsx
  src/features/product/useProducts.ts     → src/features/auth/useAuth.ts
  src/features/product/productService.ts  → src/features/auth/authService.ts
  src/features/product/product.types.ts   → src/features/auth/auth.types.ts
  src/features/product/productSlice.ts    → src/features/auth/authSlice.ts

Feature Side Effects

Some features require additional wiring. Check BEFORE marking as done:

auth / login →
  ✅ Token stored in SecureStore / Keychain (NOT AsyncStorage)
  ✅ API interceptor attaches token to all requests
  ✅ 401 handler → auto refresh token or logout
  ✅ Protected route wrapper / auth guard in navigation
  ✅ Navigation: auth stack ↔ main stack switching

list with API →
  ✅ Pagination (cursor / offset / infinite scroll)
  ✅ Pull-to-refresh
  ✅ Search/filter with debounce (300ms+)
  ✅ Empty state when no results

form / input →
  ✅ Client-side validation before submit
  ✅ Server-side error display
  ✅ Submit button disabled during loading (prevent double-tap)
  ✅ Keyboard avoidance (KeyboardAvoidingView / Scaffold)
  ✅ Unsaved changes warning on back

real-time / chat →
  ✅ WebSocket / SSE connection management
  ✅ Auto-reconnect on disconnect
  ✅ Cleanup on unmount (close connection)
  ✅ Optimistic updates with rollback

file upload / camera →
  ✅ Permission request before access
  ✅ Image compression before upload
  ✅ Upload progress indicator
  ✅ Retry on failure

Quality Gate

After creating ANY code, verify ALL of these:

✅ IMPORTS    — All import paths resolve (no broken references)
✅ STATES     — All 4 states handled: loading / error / empty / success
✅ NAVIGATION — New screen registered in navigator / router
✅ TYPES      — No 'any', no untyped params (TS/Dart/Swift/Kotlin)
✅ CLEANUP    — useEffect cleanup / dispose / [weak self] / viewModelScope
✅ ERRORS     — try/catch on ALL async operations
✅ HARD BANS  — None of the Hard Bans violated (see below)
✅ NAMING     — Matches existing project conventions exactly
✅ TESTS      — Unit test for service/usecase (if project has tests)

⛔ DO NOT tell user "done" until ALL gates pass.

Smart Loading

After auto-detect, load ONLY relevant files:

| Detected | Load | Status | |----------|------|--------| | React Native / Expo | react-native/react-native.md | 🔴 PRIMARY | | Flutter | flutter/flutter.md | 🔴 PRIMARY | | iOS Native | ios/ios-native.md | 🔴 PRIMARY | | Android Native | android/android-native.md | 🔴 PRIMARY | | All platforms | shared/code-review.md | 🔴 ALWAYS | | All platforms | shared/bug-detection.md | 🔴 ALWAYS | | All platforms | shared/prompt-engineering.md | 🟡 ALWAYS | | All platforms | shared/release-checklist.md | 🟡 ON RELEASE | | All platforms | shared/common-pitfalls.md | 🟡 ON REVIEW |

Cross-platform: Flutter/RN projects also load ios/ + android/ for native modules.

Context savings: ~60% by loading only relevant platform.

Hard Bans

❌ These will CRASH, LEAK, or get REJECTED from app stores:

❌ Force unwrap (! / !! / as!) without null check
❌ Hardcoded API keys or secrets in source code
❌ Tokens in AsyncStorage / SharedPreferences / UserDefaults
❌ console.log / print / NSLog in production builds
❌ ScrollView for lists > 20 items (use FlatList / ListView.builder / LazyColumn)
❌ Network call inside render / build / Composable
❌ setState / state update after unmount / dispose
❌ Empty catch blocks (swallowing errors silently)
❌ Index as list key / no key in dynamic lists
❌ Missing error / loading / empty states (blank screen)
❌ Inline anonymous functions in render (re-creates every frame)
❌ Main thread blocking (heavy compute without background thread)
❌ Files > 500 lines (split immediately)
❌ Deep link params used without validation

If you see ANY of these in code → flag as 🔴 CRITICAL, fix immediately.

Architecture (All Platforms)

Presentation (UI) → Domain (Business Logic) ← Data (API, DB, Cache)

Domain depends on NOTHING. Dependencies flow INWARD only.

| Principle | Rule | |-----------|------| | S — Single Responsibility | 1 file = 1 purpose. Max 300 lines. | | O — Open/Closed | Extend via composition, not modification. | | L — Liskov | Mocks behave like real implementations. | | I — Interface Segregation | Small focused interfaces. No god-services. | | D — Dependency Inversion | Inject services. Never hardcode singletons. |

UI State Machine (ALL frameworks)

LOADING → skeleton / shimmer / spinner
SUCCESS → show data
ERROR   → error message + retry button
EMPTY   → helpful empty message
⛔ NEVER show a blank screen.

Auto-Think (Both Modes)

Before ANY action, generate a think block. Never skip this.

<think>
TASK:       [what user asked]
TASK TYPE:  [create feature / create screen / fix bug / review / optimize / refactor / release]
FRAMEWORK:  [detected]
LANGUAGE:   [detected]
MODE:       [default / local]

# If local mode:
REFERENCE:  [most similar existing feature + path]
DATA SOURCE:[detected from reference: axios / fetch / Firebase / GraphQL]
STATE MGMT: [detected from reference: Redux / Zustand / MobX / etc.]

# Plan:
FILES:      [files to create/modify + why]
SIDE EFFECTS: [auth needs interceptor? list needs pagination?]
STATES:     loading / error / empty / success
RISKS:      [what could break]

# Quality gate:
VERIFY:     [how to confirm it works]
</think>

Reference Files

skill-mobile-mt/
├── SKILL.md                          ← You are here
├── AGENTS.md                         ← Multi-agent config
├── react-native/react-native.md      ← RN patterns + Clean Architecture
├── flutter/flutter.md                ← Flutter patterns + Clean Architecture
├── ios/ios-native.md                 ← iOS Swift MVVM + Clean Architecture
├── android/android-native.md         ← Android Kotlin + Clean Architecture
└── shared/
    ├── code-review.md                ← 🔴 Senior review checklist
    ├── bug-detection.md              ← 🔴 Auto bug scanner
    ├── prompt-engineering.md         ← 🟡 Auto-think templates
    ├── release-checklist.md          ← 🟡 Before shipping to app store
    └── common-pitfalls.md            ← 🟡 Problem → Symptoms → Solution