export interface UploadResult {
    id: string;
    gcsUri: string;
    signedUrl: string;
    filename: string;
    contentType: string;
    sizeBytes: number;
    expiresAt: Date;
}
export interface UploadServiceOpts {
    bucket: string;
    prefix: string;
    ttlMs: number;
    maxSizeMb: number;
}
/**
 * Handles temporary image uploads to GCS for MCP detection tools.
 * Files are stored under `{prefix}/{id}/{filename}` with signed URL access.
 * GCS lifecycle policy auto-deletes after 1 day; in-app TTL is shorter (1 hour default).
 */
export declare class UploadService {
    private storage;
    private bucketName;
    private prefix;
    private ttlMs;
    private maxSizeBytes;
    constructor(opts: UploadServiceOpts);
    /**
     * Upload a file buffer to GCS and return a signed URL.
     */
    upload(buffer: Buffer, filename: string, contentType: string): Promise<UploadResult>;
    /**
     * Generate a signed URL for an existing upload by ID and filename.
     */
    getSignedUrl(id: string, filename: string): Promise<string | null>;
    /**
     * Delete an upload by ID (best-effort cleanup).
     */
    delete(id: string): Promise<void>;
}