Detect the repo's convention. Read settings.gradle(.kts), the existing module families and their names, build-logic plugin ids, and one neighbouring feature. Repo-local names, module families, and DI style win; the shapes below are the fallback when the repo has no convention.
Look for an existing owner. Search the target modules for a contract that already covers the behavior. If one exists, converge callers onto it instead of creating new files.

Choose the smallest boundary. Walk the ladder and stop at the first rung a named caller needs: private file -> feature package -> feature module -> api + impl -> api + impl + ui -> core capability. MUST read module-boundaries.md before creating any api/impl/ui/assertions module or package boundary note.

Proven need	Smallest shape
Feature stays local to one module	one unsplit module
Another module navigates to, launches, or compiles against it	`api` + `impl`
A named consumer outside `impl` renders the same concrete surface	`api` + `impl` + `ui`

Place ownership. api holds the whole navigation contract (destination type, arguments, deep link, result, public events, navigateTo<Feature>); impl holds holder, ViewModel, state, content, entry binding, and any Activity. MUST read module-layout.md before choosing a module family or core capability, and feature-package-structure.md before adding feature subpackages.
Check dependency edges. Forbidden: api -> impl, api -> ui, ui -> impl, navigating caller -> impl/-> ui, repository-api -> repository impl, repository -> feature, core -> feature, designsystem -> feature, domain -> UI/Android/DTO. MUST run the Dependency Edge Verification in module-layout.md for every edge you add.
Entry contracts. MUST read compose-entry-contracts.md before an api module exposes a @Composable, Activity, provider, or registry entry.
DI and build logic. MUST read di-build-logic.md before editing build-logic, convention plugins, Gradle dependency blocks, or Hilt modules.
Moving existing code. MUST read split-and-migration.md before moving any file, package, or module; it owns the pre-edit gate, copy-first parity, end state, and split hazards.
Split files. Apply the file rules in current-guidance.md.
Review. Run review-checklist.md before reporting.

Source Map

Need	Reference
Split decision, ownership, naming, example packet	module-boundaries.md
Module families, core capabilities, edges	module-layout.md
Feature package gate	feature-package-structure.md
Compose/Activity entry, registries, Navigation 3	compose-entry-contracts.md
Convention plugins, Hilt placement, cleanup	di-build-logic.md
Moving code, bridges, split hazards	split-and-migration.md
External Android skill surfaces	skill-source-coverage.md
Architecture tracks and runtime boundaries	android-architecture

Do Not

Create modules to fill a template shape; each module needs a named caller.
Extract ui for a preview, an internal package, or the feature's own Activity.
Hide a single concrete composable behind an interface with one implementation and one @Binds; call the composable directly.
Fix a wrong edge by moving it behind a DI interface.
Copy a reference app's module list, plugin ids, or package names.

Stop If

You cannot name the caller or consumer that needs the boundary.
The package boundary note cannot name a forbidden import.
A move adds glue to the host module and you cannot say what still has to move and when the glue is removed.
A UI-bearing move would change what renders before parity evidence exists.

Verification

Compile each changed module and at least one real consumer; compile a navigating caller against api alone when api changed.
Run the forbidden-import and Gradle-edge searches from module-layout.md.
For build-logic changes, follow the verification order in di-build-logic.md.

Report

Chosen shape: one unsplit module | api + impl | api + impl + ui | core capability | package only.
The caller or consumer that justifies it, and why the next-smaller boundary fails.
Dependency edges added and removed, and the integration owner.
For moves: host files deleted vs added, remaining bridges, and whether the migration is complete or partial.

When changing routing or this card, confirm the route loads this entrypoint and that every link resolves.

android-module-structure

Android Module Structure

Steps