export type AgentPromptAttachmentReadError = "read-failed" | "too-large" | "not-utf8";
export interface AgentPromptAttachment {
    name: string;
    type?: string;
    size?: number;
    text?: string;
    /** Length of the whole file when `text` holds only its head. */
    totalChars?: number;
    readError?: AgentPromptAttachmentReadError;
    dataUrl?: string;
}
export declare function formatPromptWithAttachments(prompt: string, attachments: readonly AgentPromptAttachment[]): string;
/**
 * Attachments come back from run metadata as untrusted JSON. Every field the
 * formatter reads must survive here with its type checked: dropping
 * `totalChars` sends a file's head as if it were the whole file, and dropping
 * `readError` turns an unreadable file into a filename with no explanation.
 */
export declare function promptAttachmentsFromMetadata(value: unknown): AgentPromptAttachment[];
export declare function escapePromptAttachmentAttribute(value: string): string;