android-modularization

Android Modularization

When To Use

• Use this skill when the request is about: android module split, feature modularization in android, break cyclic module dependency.
• Primary outcome: Design Android repositories with feature, core, and build-logic modules that scale without cyclic dependencies.
• Reach for this skill when the problem is dependency direction, API ownership, or feature/data/core boundaries, not task-level build speed tuning.
• Handoff skills when the scope expands:
• android-gradle-build-logic
• android-architecture-clean

Workflow

1. Map the current module graph first: app, feature, data, core, build-logic, and any dynamic-feature or test-only modules.
2. Identify which direction is wrong: feature-to-feature coupling, framework leakage into domain/data, API surface too wide, or duplicated shared code with unclear ownership.
3. Split by ownership and change rate, not by abstract theory; create the smallest module boundary that removes the current coupling problem.
4. Keep api vs implementation, public surface area, and test fixture ownership explicit so the new boundary stays stable.
5. Hand off build-speed or plugin-architecture issues only after the module graph itself is coherent.

Guardrails

• Prefer official Android and Kotlin guidance over custom local conventions when they conflict.
• Keep public APIs boring and explicit; avoid clever abstractions that hide Android lifecycle costs.
• Do not mix architectural cleanup with product behavior changes unless the request explicitly needs both.
• Document any compatibility constraints that will affect old modules or generated code.
• Avoid over-modularizing a small codebase when the real need is a single clearer ownership boundary.

Anti-Patterns

• Sprinkling helpers across modules without a clear ownership boundary.
• Introducing framework-specific code into pure domain or data layers.
• Refactoring every adjacent file when only one contract needed to change.
• Leaving migration notes implied instead of writing them down.
• Treating module count as the goal instead of build isolation and dependency clarity.