import type { AgentEvent, CommandDefinition, ContextProvider, Extension, ExtensionEvent, ExtensionLifecycleEventName, InstructionInjector, Skill, StopHook, ToolDefinition } from "./contracts.js";
import { type ContributionRegistries } from "./contributions.js";
import { type MiddlewareRegistry } from "./middleware.js";
import { type PermissionPolicy } from "./security.js";
export type ExtensionEventHandler = (event: ExtensionEvent) => void | Promise<void>;
export type ExtensionErrorPolicy = "event" | "throw";
export interface ExtensionLoadPolicy {
    /** When set, only listed extension names may load. */
    readonly allowList?: readonly string[];
    /**
     * Host signature / attestation check. Return false or throw to deny.
     * Unsigned extensions fail closed when this callback is provided.
     */
    readonly verifySignature?: (extension: Extension) => boolean | Promise<boolean>;
}
export interface ExtensionKernelOptions {
    readonly registries?: ContributionRegistries;
    readonly middleware?: MiddlewareRegistry;
    readonly errorPolicy?: ExtensionErrorPolicy;
    readonly secrets?: readonly (string | undefined)[];
    readonly permission?: PermissionPolicy;
    /** Optional allow-list / signature policy evaluated before `setup`. */
    readonly loadPolicy?: ExtensionLoadPolicy;
}
export interface ExtensionEventBus {
    on(type: ExtensionLifecycleEventName | string, handler: ExtensionEventHandler): () => void;
    emit(event: ExtensionEvent): Promise<void>;
}
export interface LoadedExtension {
    readonly name: string;
    /** Remove this extension's registry contributions and middleware/event subscriptions.
     *  Best-effort and idempotent; side effects outside the registries are NOT unwound. */
    dispose(): void;
}
export interface ExtensionKernel {
    readonly registries: ContributionRegistries;
    readonly middleware: MiddlewareRegistry;
    readonly events: ExtensionEventBus;
    load(extensions: readonly Extension[]): Promise<LoadedExtension[]>;
}
export declare function createExtensionEventBus(options?: Pick<ExtensionKernelOptions, "errorPolicy" | "secrets">): ExtensionEventBus;
export declare function createExtensionKernel(options?: ExtensionKernelOptions): ExtensionKernel;
export interface AgentEventBridgeOptions {
    /** Bridge-side failure (a source error, or a bus listener that throws under `errorPolicy: "throw"`).
     *  Never rethrown — the bridge must not fail the run it is observing. */
    readonly onError?: (error: unknown) => void;
}
/**
 * Forward an `AgentEvent` iterable onto the extension bus, one mapped lifecycle event at a time
 * (plan 106 R2). Handlers run in event order and never in the run's path, so a slow or throwing
 * listener cannot stall or fail the observed run. Returns an unsubscribe that stops forwarding and
 * releases the source iterator.
 */
export declare function forwardAgentEvents(source: AsyncIterable<AgentEvent>, events: Pick<ExtensionEventBus, "emit">, options?: AgentEventBridgeOptions): () => void;
/** Host-owned activation: copy contributed entries into the `createAgent()`
 *  fields that accept plain arrays. Contributions stay inert until the host
 *  passes the returned fields into runtime config. Array slots only —
 *  single-slot builders (`inputBuilder`/`promptBuilder`), `compaction`,
 *  `retry`, provider/model selection, and skill activation remain host-owned
 *  decisions; `commands` are for host RPC surfaces, not an `AgentConfig` field. */
export interface ActivatedKernelConfig {
    readonly tools: readonly ToolDefinition[];
    readonly skills: readonly Skill[];
    readonly instructionInjectors: readonly InstructionInjector[];
    readonly context: readonly ContextProvider[];
    /** Run-end stop hooks (plan 106 R1); pass to `createAgent({ stopHooks })`. */
    readonly stopHooks: readonly StopHook[];
    /** For host command surfaces (CLI/RPC/UI); not part of `AgentConfig`. */
    readonly commands: readonly CommandDefinition[];
    /** The kernel middleware registry itself; runs only when passed to runtime config. */
    readonly middleware: MiddlewareRegistry;
}
export declare function activateKernel(kernel: ExtensionKernel): ActivatedKernelConfig;