Mod Developers

Depend on ECHO Core for shared service contracts and use optional lookups for every cross-addon connection.

Gradle

Use ECHO Core as an implementation dependency. Optional addon integrations should be compileOnly with runtime guarded by EchoIntegrations or EchoOptionalServices.

dependencies {

    implementation project(':echocore')

    compileOnly project(':echoterminal')

    compileOnly project(':echoindex')

}

Services

Prefer:

EchoOptionalServices.terminalOrNoOp().registerDashboardCard(cardId);

EchoOptionalServices.index().ifPresent(index -> index.refresh());

Avoid direct ModList checks outside setup code unless the integration is too small to need a service.

Provider Rules

• Providers must be duplicate-safe and id-stable.

• Provider failures should log and no-op, never crash the addon.

• Do not read or write another addon's saved data directly.

• Use ECHO Core registries, datapack schemas, service contracts, and optional bridges.

Ashfall

Ashfall is a flagship content pack. Generic addons should expose generic APIs and fallback content; Ashfall modules register Ashfall missions, themes, map layers, scans, sound rules, route records, and lore into those APIs.

1.3.4 Public API Labels

Use API_STABILITY.md as the source of truth for Stable/Beta/Experimental/Internal API surfaces. Use OPTIONAL_INTEGRATIONS.md for safe no-op integration patterns.

Minimal optional provider example:

public void registerEchoIntegrations() {

    EchoCoreServices.indexService().registerProvider(myProvider);

    EchoCoreServices.holoMapService().registerMarkerProvider(myMarkers);

}

The call must remain safe if Index or HoloMap is not installed because Core supplies no-op services for absent optional integrations.