/**
 * Structured JSON logger for mcp-server-dig.
 * Supports MCP Logging Protocol when server is available, falls back to stderr.
 * Log level controlled by DIG_LOG_LEVEL environment variable.
 */
import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
type LogLevel = "debug" | "info" | "warn" | "error";
export declare class Logger {
    private readonly minLevel;
    private mcpServer;
    constructor(level?: LogLevel);
    setServer(server: McpServer): void;
    debug(msg: string, context?: Record<string, unknown>): void;
    info(msg: string, context?: Record<string, unknown>): void;
    warn(msg: string, context?: Record<string, unknown>): void;
    error(msg: string, context?: Record<string, unknown>): void;
    private log;
    private stderrFallback;
}
/** Singleton logger instance. */
export declare const logger: Logger;
export {};