Implement — Android Feature Implementation

Implement — Android Feature Implementation

You implement Android feature layers strictly following the project's architectural rules.

Input

Task from user: $ARGUMENTS

Step 1: Determine the working mode

Automatically determine the task type:

CREATE mode — feature does not exist

Triggers:

• User asks to create a new screen/feature
• Feature not found by Glob patterns in the project
• Full structure needs to be built from scratch

MODIFY mode — feature exists, needs to be extended

Triggers:

• User asks to add/change functionality
• Feature found in the project
• Needs to be extended, not built from scratch

REFACTOR mode — feature exists, needs to be brought to standard

Triggers:

• User asks to refactor/migrate
• A list of violations received from review skill
• Needs to be brought to the architectural standard
• DI migration (Kodein → Koin)
• Screen/View separation

FIX mode — fixing specific violations

Triggers:

• A list of Issues received from review or test-ui skill
• Specific problems need to be fixed
• Category → files mapping:
  • [Structure] → packages and files
  • [Screen] → {Feature}Screen.kt
  • [View] → {Feature}View.kt
  • [ViewModel] → {Feature}ViewModel.kt
  • [ViewState/Event/Action] → corresponding files
  • [UseCase] → *UseCase.kt
  • [Repository] → *Repository.kt
  • [DI] → *DiModule.kt / *Module.kt
  • [Rendering] → {Feature}View.kt
  • [Interaction] → {Feature}View.kt + ViewModel
  • [Navigation] → {Feature}Screen.kt + ViewModel
  • [Data] → ViewModel + ViewState
  • [Accessibility] → {Feature}View.kt
  • [Crash] → ViewModel / UseCases

Step 2: Project preparation

1. Determine the base package — from CLAUDE.md or existing files
2. Determine the DI framework — koin or kodein from build.gradle or existing modules
3. Determine navigation — from existing Screen files
4. Find BaseSharedViewModel — full import path
5. Find UseCase interface — full import path
6. Read the rules — $CLAUDE_PLUGIN_ROOT/rules/android-core.md (required)

Step 3: Execute by mode

---

CREATE mode

Read references: $CLAUDE_PLUGIN_ROOT/skills/implement/references/architecture.md, $CLAUDE_PLUGIN_ROOT/skills/implement/references/base-viewmodel.md, $CLAUDE_PLUGIN_ROOT/skills/implement/references/theme-system.md Use examples/ as a template for each file.

Creation order:

1. Create the folder structure:

   feature/{featureName}/
       presentation/screen/
       presentation/view/
       presentation/viewmodel/
       domain/usecase/
       domain/repository/
       data/datasource/
       data/repository/
       di/
   

2. Generate files in this order:
   • {Feature}ViewState.kt — data class with default values
   • {Feature}ViewEvent.kt — sealed class of UI events
   • {Feature}ViewAction.kt — sealed class of one-time actions
   • {Feature}ViewModel.kt — extends BaseSharedViewModel
   • {Feature}Screen.kt — thin adapter
   • {Feature}View.kt — pure UI with Preview
   • Use cases — one per action
   • I{Feature}Repository.kt — interface
   • {Feature}Repository.kt — implementation
   • DataSources — Local and/or Remote
   • {Feature}DiModule.kt — DI module

---

MODIFY mode

Read references: $CLAUDE_PLUGIN_ROOT/skills/implement/references/modification-rules.md

1. Read all feature files (Screen, View, ViewModel, ViewState, ViewEvent, ViewAction, UseCases, Repository, DataSources, DI)
2. Plan changes — what to add/modify
3. Safe modification rules:
   • Do not break existing contracts (do not remove fields, do not change signatures)
   • New logic — only in ViewModel
   • New UI — only in View
   • New data — through UseCase → Repository → DataSource
   • Each new class — in a separate file
   • Update the DI module

---

REFACTOR mode

Read references: $CLAUDE_PLUGIN_ROOT/skills/implement/references/migration-guide.md, $CLAUDE_PLUGIN_ROOT/skills/implement/references/architecture.md

1. Audit — check against the checklist from architecture.md
2. Migration plan:
   • Create missing package structure
   • Split files (separate classes)
   • Create missing layers
   • Refactor ViewModel to BaseSharedViewModel
   • Separate Screen and View
   • Migrate DI (if needed)
3. Execution — atomic steps, code compiles after each one
4. Validation — re-audit

---

FIX mode

1. Get the list of Issues (from review or test-ui)
2. For each issue: find the file → find the problematic spot → fix strictly according to the rule
3. Do not touch code that already conforms to the standard
4. UI state rule: If review flags remember/LaunchedEffect in Screen — move them to View, do NOT delete them. PagerState, ScrollState, LazyListState and related snapshotFlow belong in View, never in Screen.
5. After all fixes — validation

Step 4: Validation (for all modes)

• Screen contains no logic, remember, computations, no UI state (PagerState etc.)
• View is in a separate file with Preview in {App}Theme
• View contains no business logic; UI state (PagerState, ScrollState) is allowed in View
• ViewModel extends BaseSharedViewModel, no Compose imports
• UseCase extends UseCase<Params, T>, execute() not operator fun
• UseCase returns Result
• Repository has an I{Feature}Repository interface
• Each class is in a separate file
• Package structure is correct
• DI module contains all dependencies

Step 5: Output

1. Summary — what was done and in which mode
2. Files — list of created/modified/deleted files
3. Full code — code of all files
4. Architecture validation — confirmation of rule compliance