/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { Event } from '../events/event.js';
import { BaseNode } from './base_node.js';
import { NodeLike } from './graph.js';
import { NodeContext } from './node_context.js';
import { BuildNodeOptions } from './utils/workflow_graph_utils.js';
/** Options accepted by {@link node}. */
export type NodeOptions = BuildNodeOptions;
/**
 * Wraps a {@link NodeLike} (function, tool, agent, or existing node) into a
 * {@link BaseNode}, optionally overriding its properties.
 *
 * The TypeScript form is a plain function (there is no `@node` decorator form,
 * unlike Python). Examples:
 *
 * ```ts
 * const a = node(myFunction, {name: 'classify'});
 * const b = node(myTool);
 * ```
 *
 * Ported from `google/adk-python` `workflow/_node.py::node`.
 */
export declare function node(nodeLike: NodeLike, options?: NodeOptions): BaseNode;
/**
 * A base class designed for subclassing. Implement {@link runNodeImpl} to
 * provide node logic; subclasses inherit the schema/retry/timeout machinery of
 * {@link BaseNode}.
 *
 * Named `WorkflowNode` (not `Node`) to read consistently with `Workflow` and
 * `WorkflowConfig`, and to avoid shadowing the DOM / `@types/node` `Node`
 * global in the flat `@google/adk` namespace. The `node()` factory remains the
 * ergonomic way to wrap a function/tool/agent.
 *
 * Mirrors `google/adk-python` `workflow/_node.py::Node`. The `parallel_worker`
 * capability is added in Phase 6.
 */
export declare abstract class WorkflowNode<TInput = unknown, TOutput = unknown> extends BaseNode<TInput, TOutput> {
    /**
     * Implement node execution logic here. May yield `Event`s, raw values, or
     * `null` (normalized by {@link BaseNode.run}).
     */
    protected abstract runNodeImpl(ctx: NodeContext, input: TInput): AsyncGenerator<Event | TOutput | unknown, void, void>;
    protected runImpl(ctx: NodeContext, input: TInput): AsyncGenerator<Event | TOutput | unknown, void, void>;
}