Versioned shared backbone for apps: published libraries (MVI runtime, design system, image), unified build and style tooling, and Claude Code AI assets that teach assistants to adopt and use conventions.
A shared backbone for Kotlin Multiplatform apps — published libraries, build tooling, conventions, and the Claude Code assets that teach an AI assistant how to use them.
Ship more than one Kotlin Multiplatform app on the same stack and the shared parts quietly drift — the same TOAD presentation runtime, the same Compose design language, the same ktlint rules and Gradle conventions, duplicated and slowly diverging. rhaydus-foundation is the single, versioned home for everything they share, so a fix or an improvement lands once and every consuming app inherits it.
It ships three things most "shared module" repos don't bother to keep together:
nl.rhaydus:*, version 0.2.0)build-logic/): , , , — uniform module setup (SDK/JDK levels, the Android+iOS seam, the test stack, Compose).graph LR
editorial["designsystem-editorial<br/><i>editorial language</i>"] --> core["designsystem-core<br/><i>neutral skeleton</i>"]
image["designsystem-image<br/><i>async images</i>"] --> core
image -. brings .-> coil["Coil"]
toad["toad<br/><i>presentation runtime</i>"]
coreui["core-ui<br/><i>non-visual seams</i>"]
An app that wants a different look depends on designsystem-core alone and never pulls the editorial language or Coil — the opinionated layers are opt-in by design.
// build.gradle.kts
dependencies {
implementation("nl.rhaydus:toad:0.2.0")
implementation("nl.rhaydus:designsystem-core:0.2.0")
implementation("nl.rhaydus:designsystem-editorial:0.2.0") // opt-in
implementation("nl.rhaydus:designsystem-image:0.2.0") // opt-in (pulls Coil)
}
Artifacts publish to Maven Central under the nl.rhaydus group (verified by DNS, no server) — consumers need no credentials, just mavenCentral().
// settings.gradle.kts
dependencyResolutionManagement {
versionCatalogs {
create("rhaydus") { from("nl.rhaydus:catalog:0.2.0") }
}
}
App-only libraries (Apollo, Room, etc.) stay in your app's own catalog.
While iterating on the foundation and an app together, skip the publish cycle entirely:
# <app>/local.properties
foundation.local=true
The app's settings.gradle.kts reads that flag and includeBuild("../rhaydus-foundation"); Gradle substitutes the published coordinates for local source automatically — no version bumps, instant cross-repo edits. Flip it back to return to the pinned release.
/plugin marketplace add CinqueIzumi/rhaydus-foundation
/plugin install rhaydus-kotlin@rhaydus
The rhaydus-kotlin plugin makes a consuming app's AI assistant fluent in the foundation. It ships:
Every agent reads CAPABILITIES.md first — so it reuses what already exists and stays correct for the exact version a project is pinned to, rather than working from a memorized snapshot.
One version covers the whole release: foundation.version in gradle.properties drives all seven published artifacts, and a verifyPluginVersion build gate locks the Claude plugin's version to it (the build fails if they drift). Bump them together; a tagged push (v*) publishes to Maven Central via CI.
./gradlew build # compile all targets (jvm/android/ios) + tests + gates
./gradlew publishToMavenLocal # local smoke test of the real artifacts
./gradlew publishAndReleaseToMavenCentral # release (normally done by CI on a v* tag)
Publishing credentials (Central Portal token + PGP key) are maintainer-only, supplied via env/Gradle properties and never committed — see .github/workflows/publish.yml.
A 0.x release: the public API may still change between minor versions before 1.0, so pin a version when you depend on it. Every release builds on all targets (Android / iOS / Desktop) and is verified against a sample consumer before it ships.
MIT © CinqueIzumi
| Module | Coordinate | What it gives you |
|---|
| TOAD runtime | nl.rhaydus:toad | The home-grown MVI-style presentation framework: ToadScreenModel, UiState/UiAction/UiEvent, Collector, ActionScope. |
| Core UI seams | nl.rhaydus:core-ui | Non-visual seams: AppDispatchers, date/time/number formatting. |
| Design system — core | nl.rhaydus:designsystem-core | The design-agnostic Compose skeleton: theme scaffold, layout primitives (window-size classes, two-pane, content-width caps), modifiers, motion + reduced-motion seam, haptics, the button family. |
| Design system — editorial | nl.rhaydus:designsystem-editorial | Opt-in editorial design language: shared type-role contract + components (section header, hero stat, drop cap, search field, pull-to-refresh eyebrow). |
| Design system — image | nl.rhaydus:designsystem-image | Opt-in async images on Coil: plain, placeholder, and shimmer variants. |
| Version catalog | nl.rhaydus:catalog | The shared third-party version set, consumable as a Gradle version catalog. |
| ktlint rules | nl.rhaydus:ktlint-rules | 10 custom layout rules (one-per-line arg wrapping, trailing commas, blank-line rules, sibling-composable spacing, and more) with auto-fix. |
rhaydus.android.libraryrhaydus.kmp.libraryrhaydus.android.composerhaydus.kmp.composemobileMaindocs/): see CAPABILITIES.md (the index of everything available), plus architecture, TOAD, code-style, and design-system foundations.| Agent / asset | Role |
|---|
rhaydus-adopt | Onboards a project: wires the catalog, convention plugins, and includeBuild; writes a managed routing block into the app's CLAUDE.md; flags prerequisite migrations. |
rhaydus-logic | Builds feature logic — the TOAD state/action contract, ScreenModel, use cases, data. |
rhaydus-ui | Builds feature UI — the stateless Compose render, from the foundation design system and the app's own brand doc. |
code-reviewer / unit-test-writer | Review and tests, tuned to the conventions. |
style-check skill | Auto-fix mechanizable style, then run the project's gates. |
| docs-first hook | Nudges reading the docs (and CAPABILITIES.md) before exploring. |
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