export type LangMessageRole = "user" | "assistant" | "tool-results";
export type LangMessageContent = string | LangContentPart[] | ToolRequest[] | ToolResult[];
export type LangMessageMeta = Record<string, any>;
export type LangContentPart = {
    type: "text";
    text: string;
} | {
    type: "image";
    image: LangContentImage;
    alt?: string;
} | {
    type: "reasoning";
    text: string;
};
/**
 * Interface for tool requests that can be sent to language models
 */
export interface ToolRequest {
    callId: string;
    name: string;
    arguments: Record<string, any>;
}
/**
 * Interface for tool execution results
 */
export interface ToolResult {
    toolId: string;
    name: string;
    result: any;
}
export type LangContentImage = {
    kind: "url";
    url: string;
} | {
    kind: "base64";
    base64: string;
    mimeType?: string;
} | {
    kind: "bytes";
    bytes: ArrayBuffer | Uint8Array;
    mimeType?: string;
} | {
    kind: "blob";
    blob: Blob;
    mimeType?: string;
};
export type LangImageOutput = {
    url?: string;
    base64?: string;
    mimeType?: string;
    width?: number;
    height?: number;
    metadata?: Record<string, any>;
};
/**
 * Built-in tools provided by the language model provider
 * These tools don't require handlers as they're executed by the provider
 */
export type BuiltInLangTool = {
    name: string;
    [key: string]: any;
};
/**
 * Union type for all tool types: custom functions with handlers and built-in provider tools
 */
export type LangTool = LangToolWithHandler | BuiltInLangTool;
export type LangToolWithHandler = {
    name: string;
    description: string;
    parameters: Record<string, any>;
    handler: (args: Record<string, any>) => any | Promise<any>;
};
export type LangMessageItem = LangMessageItemText | LangMessageItemReasoning | LangMessageItemImage | LangMessageItemTool | LangMessageItemToolResult;
export type LangMessageItemText = {
    type: "text";
    text: string;
};
export type LangMessageItemReasoning = {
    type: "reasoning";
    text: string;
};
export type LangMessageItemImage = {
    type: "image";
    url?: string;
    base64?: string;
    mimeType?: string;
    width?: number;
    height?: number;
    metadata?: Record<string, any>;
};
export type LangMessageItemTool = {
    type: "tool";
    name: string;
    callId: string;
    arguments: Record<string, any>;
};
export type LangMessageItemToolResult = {
    type: "tool-result";
    name: string;
    callId: string;
    result: any;
};
export declare class LangMessage {
    role: LangMessageRole;
    items: LangMessageItem[];
    meta?: Record<string, any>;
    constructor(role: LangMessageRole, text: string, meta?: Record<string, any>);
    constructor(role: LangMessageRole, items: LangMessageItem[], meta?: Record<string, any>);
    get text(): string;
    get reasoning(): string;
    get object(): any | null;
    get toolRequests(): LangMessageItemTool[];
    get toolResults(): LangMessageItemToolResult[];
    get images(): LangMessageItemImage[];
}
export declare class LangMessages extends Array<LangMessage> {
    availableTools?: LangTool[];
    finished: boolean;
    aborted: boolean;
    instructions?: string;
    constructor();
    constructor(initialPrompt: string, opts?: {
        tools?: LangTool[];
    });
    constructor(initialMessages: LangMessage[], opts?: {
        tools?: LangTool[];
    });
    constructor(initialMessages: LangMessages, opts?: {
        tools?: LangTool[];
    });
    constructor(initialMessages: {
        role: LangMessageRole;
        items: LangMessageItem[];
        meta?: Record<string, any>;
    }[], opts?: {
        tools?: LangTool[];
    });
    /**
     * Last assistant message as text
     */
    get answer(): string;
    get object(): any | null;
    get assistantImages(): LangImageOutput[];
    get userImages(): LangImageOutput[];
    private getImagesFromLastMessage;
    addUserMessage(content: string): this;
    addUserItems(items: LangMessageItem[]): this;
    addToolResultsMessage(items: LangMessageItemToolResult[]): this;
    addUserImages(image: LangContentImage): this;
    addUserImages(images: LangContentImage[]): this;
    private createImageMessageItem;
    private static encodeBytesAsBase64;
    addAssistantMessage(content: string, meta?: Record<string, any>): this;
    addAssistantItems(items: LangMessageItem[], meta?: Record<string, any>): this;
    executeRequestedTools(meta?: Record<string, any>): Promise<LangMessage | null>;
    toString(): string;
}
/**
 * Ensure every assistant tool call has a follow-up tool-results message to keep provider chains valid.
 */
export declare function fixToolResultsIfNeeded(messages: LangMessages | LangMessage[]): void;