> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentium.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Runtime registries

> Resolve versioned driver and policy references against host-approved implementations.

Resolve versioned driver and policy references against host-approved implementations. Read the [runtime registries guide](/harness/manifests) for examples, defaults, and behavior.

These declarations cover every public export in this category. Import from `@agentium/harness`. Types such as `ChatMessage`, `RunContext`, and `ExecutionServices` come from [`@agentium/core`](/api-reference/core). A `?` marks an optional field.

## HarnessRegistryEntry

```typescript theme={null}
export interface HarnessRegistryEntry<T> extends HarnessRegistryReference {
    implementation: T;
}
```

## HarnessRegistryReference

```typescript theme={null}
export interface HarnessRegistryReference {
    id: string;
    version: number;
}
```

## HarnessRuntimeBindings

```typescript theme={null}
export interface HarnessRuntimeBindings {
    driver?: ExecutionDriver;
    controller?: StepController;
    contextPolicy?: ContextPolicy;
    completionPolicy?: CompletionPolicy;
    modelRoles?: Readonly<Record<string, string>>;
}
```

## HarnessRuntimeReferences

```typescript theme={null}
export interface HarnessRuntimeReferences {
    driver?: HarnessRegistryReference;
    controller?: HarnessRegistryReference;
    contextPolicy?: HarnessRegistryReference;
    completionPolicy?: HarnessRegistryReference;
    /** Role -> approved host binding name; credentials/providers stay host-owned. */
    modelRoles?: Readonly<Record<string, string>>;
}
```

## HarnessRuntimeRegistry

```typescript theme={null}
export interface HarnessRuntimeRegistry {
    driver?: readonly HarnessRegistryEntry<ExecutionDriver>[];
    controller?: readonly HarnessRegistryEntry<StepController>[];
    contextPolicy?: readonly HarnessRegistryEntry<ContextPolicy>[];
    completionPolicy?: readonly HarnessRegistryEntry<CompletionPolicy>[];
}
```

## resolveHarnessRuntime

```typescript theme={null}
/** Registry resolution is static; it never initializes providers or executes drivers. */
export declare function resolveHarnessRuntime(definition: HarnessDefinition): HarnessRuntimeBindings;
```


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