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.
- **`ubuntu-24.04-arm`** — Lightweight/utility jobs (status checks, labelers, triage, changelog, release metadata, stale, moderation). These run only shell scripts or GitHub API calls and benefit from ARM runners' shorter queue times.
- **`ubuntu-24.04`** — Gradle-heavy jobs (CI host-check, android-check, release builds, Dokka, CodeQL, publish, dependency-submission). Pinned for reproducibility; avoid `ubuntu-latest` to prevent breakage when GitHub rolls the alias forward.
- **Desktop release matrix** — `[macos-latest, windows-latest, ubuntu-24.04, ubuntu-24.04-arm]` for cross-platform native packaging (DMG, MSI, deb/rpm/AppImage for x64 and ARM).
- **CI JVM tuning:** `gradle.properties` is tuned for local dev (8g heap, 4g Kotlin daemon). CI workflows override via `GRADLE_OPTS` env var to fit the 7GB RAM budget of standard runners: `-Xmx4g` Gradle heap, `-Xmx2g` Kotlin daemon, VFS watching disabled, workers capped at 4.
- **KMP Smoke Compile:** Use `./gradlew kmpSmokeCompile` instead of listing individual module compile tasks. The `kmpSmokeCompile` lifecycle task (registered in `RootConventionPlugin`) auto-discovers all KMP modules and depends on their `compileKotlinJvm` + `compileKotlinIosSimulatorArm64` tasks.
- **`mavenLocal()` gated:** The `mavenLocal()` repository is disabled by default to prevent CI cache poisoning. For local JitPack testing, pass `-PuseMavenLocal` to Gradle.
- **Terminal Pagers:** When running shell commands like `git diff` or `git log`, ALWAYS use `--no-pager` (e.g., `git --no-pager diff`) to prevent the agent from getting stuck in an interactive prompt.
- **Text Search:** Prefer using `rg` (ripgrep) over `grep` or `find` for fast text searching across the codebase.
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`).
