import { type GeneratedMedia, type MediaBudgetState } from "./media";
/**
 * Sanitizes unpaired/lone Unicode surrogates in text content.
 *
 * Lone surrogates (high surrogates without matching low surrogates, or vice versa)
 * can cause JSON serialization issues and downstream processing errors when sending
 * text to LLM providers. This function replaces them with the Unicode replacement
 * character (U+FFFD).
 *
 * @param content - The string to sanitize
 * @returns The string with lone surrogates replaced by U+FFFD
 */
export declare function sanitizeSurrogates(content: string): string;
export type AiSdkFormatterMessageRole = "user" | "assistant" | "tool";
export type AiSdkFormatterPart = {
    type: "text";
    text: string;
    providerOptions?: Record<string, Record<string, unknown>>;
} | {
    type: "reasoning";
    text: string;
    providerOptions?: Record<string, Record<string, unknown>>;
} | {
    type: "image";
    image: string | Uint8Array | ArrayBuffer | URL;
    mediaType?: string;
} | {
    type: "media";
    media: GeneratedMedia;
} | {
    type: "file";
    path: string;
    content: string;
} | {
    type: "tool-call";
    toolCallId: string;
    toolName: string;
    input: unknown;
    providerOptions?: Record<string, Record<string, unknown>>;
} | {
    type: "tool-result";
    toolCallId: string;
    toolName: string;
    output: unknown;
    isError?: boolean;
};
export interface AiSdkFormatterMessage {
    role: AiSdkFormatterMessageRole;
    content: string | AiSdkFormatterPart[];
}
export declare const EMPTY_CONTENT_TEXT = "ERROR: EMPTY CONTENT";
export type AiSdkMessagePart = Record<string, unknown>;
export type AiSdkMessage = {
    role: "system" | "user" | "assistant" | "tool";
    content: string | AiSdkMessagePart[];
};
export declare function toAiSdkToolResultOutput(output: unknown, isError?: boolean, mediaState?: MediaBudgetState, options?: {
    supportsImages?: boolean;
}): Record<string, unknown>;
export declare function formatMessagesForAiSdk(systemContent: string | AiSdkMessagePart[] | undefined, messages: readonly AiSdkFormatterMessage[], options?: {
    assistantToolCallArgKey?: "args" | "input";
    /**
     * Whether the target model advertises image input. When false, image
     * parts (user-attached and inside tool results) are substituted with
     * `IMAGE_UNSUPPORTED_PLACEHOLDER` text so the request stays valid for
     * text-only models while the model still learns an image was there.
     * Defaults to true. The substitution happens here at request-build
     * time only — stored conversation history is never mutated.
     */
    supportedInputModalities?: readonly string[];
}): AiSdkMessage[];