import type { Message, MessagePlugin, TokenEstimator } from './types';
/**
 * Environment functions for conversation operations.
 * Allows dependency injection for testing and custom ID generation.
 */
export interface ConversationEnvironment {
    now: () => string;
    randomId: () => string;
    estimateTokens: TokenEstimator;
    plugins: MessagePlugin[];
}
/**
 * Simple character-based token estimator.
 * Approximates ~4 characters per token (rough average for English text).
 */
export declare function simpleTokenEstimator(message: Message): number;
/**
 * Default environment using Date.toISOString(), crypto.randomUUID(), and simple token estimation.
 */
export declare const defaultConversationEnvironment: ConversationEnvironment;
/**
 * Merges a partial environment with defaults.
 * Returns a complete environment with all required functions.
 */
export declare function resolveConversationEnvironment(environment?: Partial<ConversationEnvironment>): ConversationEnvironment;
/**
 * Type guard to distinguish environment objects from message inputs.
 * Returns true if the value has environment functions but no role property.
 */
export declare function isConversationEnvironmentParameter(value: unknown): value is Partial<ConversationEnvironment>;
/**
 * Binds a partial environment to a function that accepts an environment as its last argument.
 */
export declare function withEnvironment<T extends unknown[], R>(environment: Partial<ConversationEnvironment>, fn: (...args: [...T, Partial<ConversationEnvironment>?]) => R): (...args: T) => R;
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