/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { Part as A2APart, Message, Task, TaskArtifactUpdateEvent, TaskStatusUpdateEvent } from '@a2a-js/sdk';
/**
 * Message roles.
 */
export declare enum MessageRole {
    USER = "user",
    AGENT = "agent"
}
/**
 * Task states.
 */
export declare enum TaskState {
    SUBMITTED = "submitted",
    WORKING = "working",
    COMPLETED = "completed",
    FAILED = "failed",
    CANCELED = "canceled",
    REJECTED = "rejected",
    INPUT_REQUIRED = "input-required"
}
/**
 * A2A event.
 */
export type A2AEvent = Task | Message | TaskStatusUpdateEvent | TaskArtifactUpdateEvent;
/**
 * Checks if the event is an A2A TaskStatusUpdateEvent.
 */
export declare function isTaskStatusUpdateEvent(event: unknown): event is TaskStatusUpdateEvent;
/**
 * Checks if the event is an A2A TaskArtifactUpdateEvent.
 */
export declare function isTaskArtifactUpdateEvent(event: unknown): event is TaskArtifactUpdateEvent;
/**
 * Checks if the event is an A2A Message.
 */
export declare function isMessage(event: unknown): event is Message;
/**
 * Checks if the event is an A2A Task.
 */
export declare function isTask(event: unknown): event is Task;
/**
 * Gets the metadata from an A2A event.
 */
export declare function getEventMetadata(event: A2AEvent): Record<string, unknown>;
/**
 * Checks if the event is a failed task status update event.
 */
export declare function isFailedTaskStatusUpdateEvent(event: unknown): boolean;
/**
 * Checks if the event is a terminal task status update event.
 */
export declare function isTerminalTaskStatusUpdateEvent(event: unknown): boolean;
/**
 * Checks if the event is an input required task status update event.
 */
export declare function isInputRequiredTaskStatusUpdateEvent(event: unknown): boolean;
/**
 * Gets the error message from a failed task status update event.
 */
export declare function getFailedTaskStatusUpdateEventError(event: TaskStatusUpdateEvent | Task): string | undefined;
/**
 * Creates a task submitted event.
 */
export declare function createTaskSubmittedEvent({ taskId, contextId, message, metadata, }: {
    taskId: string;
    contextId: string;
    message: Message;
    metadata?: Record<string, unknown>;
}): TaskStatusUpdateEvent;
/**
 * Creates a task with submitted status.
 */
export declare function createTask({ contextId, message, taskId, metadata, }: {
    taskId: string;
    contextId: string;
    message: Message;
    metadata?: Record<string, unknown>;
}): Task;
/**
 * Creates a task working event.
 */
export declare function createTaskWorkingEvent({ taskId, contextId, message, metadata, }: {
    taskId: string;
    contextId: string;
    message?: Message;
    metadata?: Record<string, unknown>;
}): TaskStatusUpdateEvent;
/**
 * Creates a task completed event.
 */
export declare function createTaskCompletedEvent({ taskId, contextId, metadata, }: {
    taskId: string;
    contextId: string;
    metadata?: Record<string, unknown>;
}): TaskStatusUpdateEvent;
/**
 * Creates an artifact update event.
 */
export declare function createTaskArtifactUpdateEvent({ taskId, contextId, artifactId, parts, metadata, append, lastChunk, }: {
    taskId: string;
    contextId: string;
    artifactId?: string;
    parts?: A2APart[];
    metadata?: Record<string, unknown>;
    append?: boolean;
    lastChunk?: boolean;
}): TaskArtifactUpdateEvent;
/**
 * Creates an error message for task execution failure.
 */
export declare function createTaskFailedEvent({ taskId, contextId, error, metadata, }: {
    taskId: string;
    contextId: string;
    error: Error;
    metadata?: Record<string, unknown>;
}): TaskStatusUpdateEvent;
/**
 * Creates an input required event.
 */
export declare function createTaskInputRequiredEvent({ taskId, contextId, parts, metadata, }: {
    taskId: string;
    contextId: string;
    parts: A2APart[];
    metadata?: Record<string, unknown>;
}): TaskStatusUpdateEvent;
/**
 * Creates an error message for missing input for a function call.
 */
export declare function createInputMissingErrorEvent({ taskId, contextId, parts, metadata, }: {
    parts: A2APart[];
    taskId: string;
    contextId: string;
    metadata?: Record<string, unknown>;
}): TaskStatusUpdateEvent;