This file serves as a comprehensive guide for AI agents and developers working on the `Meshtastic-Android` codebase. Use this as your primary reference for understanding the architecture, conventions, and strict rules of this project.
Meshtastic-Android is a Kotlin Multiplatform (KMP) application for off-grid, decentralized mesh networks. The goal is to decouple business logic from the Android framework, enabling future expansion to iOS and other platforms while maintaining a high-performance native Android experience.
- **Language:** Kotlin (primary), AIDL.
- **Build System:** Gradle (Kotlin DSL). JDK 17 is REQUIRED.
- **Target SDK:** API 36. Min SDK: API 26 (Android 8.0).
- **Flavors:**
-`fdroid`: Open source only, no tracking/analytics.
-`google`: Includes Google Play Services (Maps) and DataDog analytics.
- **Core Architecture:** Modern Android Development (MAD) with KMP core.
| `core:navigation` | Shared navigation keys/routes for Navigation 3, `DeepLinkRouter` for typed backstack synthesis, and `MeshtasticNavSavedStateConfig` for backstack persistence. |
| `feature/` | Feature modules (e.g., `settings`, `map`, `messaging`, `node`, `intro`, `connections`, `firmware`, `widget`). All are KMP with `jvm()` and `ios()` targets except `widget`. Use `meshtastic.kmp.feature` convention plugin. |
| `desktop/` | Compose Desktop application — first non-Android KMP target. Thin host shell relying entirely on feature modules for shared UI. Full Koin DI graph, TCP, Serial/USB, and BLE transports with `want_config` handshake. |
-**Strings:** MUST use the **Compose Multiplatform Resource** library in `core:resources` (`stringResource(Res.string.your_key)`). For ViewModels or non-composable Coroutines, use the asynchronous `getStringSuspend(Res.string.your_key)`. NEVER use hardcoded strings, and NEVER use the blocking `getString()` in a coroutine.
-**Alerts:** Use `AlertHost(alertManager)` from `core:ui/commonMain` in each platform host shell (`Main.kt`, `DesktopMainScreen.kt`). For global responses like traceroute and firmware validation, use the specialized common handlers: `TracerouteAlertHandler(uiViewModel)` and `FirmwareVersionCheck(uiViewModel)`. Do NOT duplicate inline alert-rendering logic or trigger alerts directly during composition. For shared QR/contact dialogs, use the `SharedDialogs(uiViewModel)` composable.
-**Placeholders:** For desktop/JVM features not yet implemented, use `PlaceholderScreen(name)` from `core:ui/commonMain`. Do NOT define inline placeholder composables in feature modules.
-**Theme Picker:** Use `ThemePickerDialog` and `ThemeOption` from `feature:settings/commonMain`. Do NOT duplicate the theme dialog or enum in platform-specific source sets.
-**Adaptive Layouts:** Use `currentWindowAdaptiveInfo(supportLargeAndXLargeWidth = true)` to support the 2026 Desktop Experience breakpoints. Prioritize **higher information density** and mouse-precision interactions for Desktop and External Display (Android 16 QPR3) targets. **Investigate 3-pane "Power User" scenes** (e.g., Node List + Detail + Map/Charts) using Navigation 3 Scenes and `ThreePaneScaffold` for widths ≥ 1200dp.
-**Shared helpers over duplicated lambdas:** When `androidMain` and `jvmMain` contain identical pure-Kotlin logic (formatting, action dispatch, validation), extract it to a function in `commonMain`. Examples: `formatLogsTo()` in `feature:settings`, `handleNodeAction()` in `feature:node`, `findNodeByNameSuffix()` in `feature:connections`, `MeshtasticAppShell` in `core:ui/commonMain`, and `BaseRadioTransportFactory` in `core:network/commonMain`.
-**KMP file naming:** In KMP modules, `commonMain` and platform source sets (`androidMain`, `jvmMain`) share the same package namespace. If both contain a file with the same name (e.g., `LogExporter.kt`), the Kotlin/JVM compiler will produce a duplicate class error. Use distinct filenames: keep the `expect` declaration in `LogExporter.kt` and put shared helpers in a separate file like `LogFormatter.kt`.
-**`jvmAndroidMain` source set:** Modules that share JVM-specific code between Android and Desktop apply the `meshtastic.kmp.jvm.android` convention plugin. This creates a `jvmAndroidMain` source set via Kotlin's hierarchy template API. Used in `core:common`, `core:model`, `core:data`, `core:network`, and `core:ui`.
-**Feature navigation graphs:** Feature modules export Navigation 3 graph functions as extension functions on `EntryProviderScope<NavKey>` in `commonMain` (e.g., `fun EntryProviderScope<NavKey>.settingsGraph(backStack: NavBackStack<NavKey>)`). Host shells (`app`, `desktop`) assemble these into a single `entryProvider<NavKey>` block. Do NOT define navigation graphs in platform-specific source sets.
-**Dependency Injection:** Use **Koin Annotations** with the K2 compiler plugin (`koin-plugin` in version catalog). The `koin-annotations` library version is unified with `koin-core` (both use `version.ref = "koin"`). The `KoinConventionPlugin` uses the typed `KoinGradleExtension` to configure the K2 plugin (e.g., `compileSafety.set(false)`). Keep root graph assembly in `app`.
-**Networking:** Pure **Ktor** — no OkHttp anywhere. Engines: `ktor-client-android` for Android, `ktor-client-java` for desktop/JVM. Use Ktor `Logging` plugin for HTTP debug logging (not OkHttp interceptors). `HttpClient` is provided via Koin in `app/di/NetworkModule` and `core:network/di/CoreNetworkAndroidModule`.
-**Image Loading (Coil):** Use `coil-network-ktor3` with `KtorNetworkFetcherFactory` on **all** platforms. `ImageLoader` is configured in host modules only (`app` via Koin `@Single`, `desktop` via `setSingletonImageLoaderFactory`). Feature modules depend only on `libs.coil` (coil-compose) for `AsyncImage` — never add `coil-network-*` or `coil-svg` to feature modules.
-**JetBrains fork aliases:** Version catalog aliases for JetBrains-forked AndroidX artifacts use the `jetbrains-*` prefix (e.g., `jetbrains-lifecycle-runtime-compose`, `jetbrains-navigation3-ui`). Plain `androidx-*` aliases are true Google AndroidX artifacts. Never mix them up in `commonMain`.
-**Compose Multiplatform:** Version catalog aliases for Compose Multiplatform artifacts use the `compose-multiplatform-*` prefix (e.g., `compose-multiplatform-material3`, `compose-multiplatform-foundation`). Never use plain `androidx.compose` dependencies in common Main.
-**Room KMP:** Always use `factory = { MeshtasticDatabaseConstructor.initialize() }` in `Room.databaseBuilder` and `inMemoryDatabaseBuilder`. DAOs and Entities reside in `commonMain`.
-**QR Codes:** Use `rememberQrCodePainter` from `core:ui/commonMain` (powered by `qrcode-kotlin`) for generating QR codes. Do not use Android Bitmap or ZXing APIs in common code.
-**Testing:** Write ViewModel and business logic tests in `commonTest`. Use `Turbine` for Flow testing, `Kotest` for property-based testing, and `Mokkery` for mocking. Use `core:testing` shared fakes.
-**Build-logic conventions:** In `build-logic/convention`, prefer lazy Gradle configuration (`configureEach`, `withPlugin`, provider APIs). Avoid `afterEvaluate` in convention plugins unless there is no viable lazy alternative.
- Reusable CI is split into a host job and an Android matrix job in `.github/workflows/reusable-check.yml`.
- Host job runs style/static checks, explicit Android lint tasks, unit tests, and Kover XML coverage uploads once.
- Android matrix job runs explicit assemble tasks for `app` and `mesh_service_example`; instrumentation is enabled by input and matrix API.
- Prefer explicit Gradle task paths in CI (for example `app:lintFdroidDebug`, `app:connectedGoogleDebugAndroidTest`) instead of shorthand tasks like `lintDebug`.
- Pull request CI is main-only (`.github/workflows/pull-request.yml` targets `main` branch).
- Gradle cache writes are trusted on `main` and merge queue runs (`merge_group` / `gh-readonly-queue/*`); other refs use read-only cache mode in reusable CI.
- PR `check-changes` path filtering lives in `.github/workflows/pull-request.yml` and must include module dirs plus build/workflow entrypoints (`build-logic/**`, `gradle/**`, `.github/workflows/**`, `gradlew`, `settings.gradle.kts`, etc.) so CI is not skipped for infra-only changes.
Update documentation continuously as part of the same change. If you modify architecture, module targets, CI tasks, validation commands, or agent workflow rules, update the relevant docs (`AGENTS.md`, `.github/copilot-instructions.md`, `GEMINI.md`, `docs/agent-playbooks/*`, `docs/kmp-status.md`, and `docs/decisions/architecture-review-2026-03.md`).
