/**
 * Logger Implementation for MCP Server
 *
 * Provides a configurable logging system that writes to stderr
 * (to avoid polluting stdout which is used for MCP protocol messages).
 */
import type { LogLevel as MCPLogLevel, Logger as MCPLogger } from '../types';
/**
 * Log level enum for backward compatibility
 */
export declare enum LogLevel {
    DEBUG = 0,
    INFO = 1,
    WARN = 2,
    ERROR = 3,
    SILENT = 4
}
/**
 * Logger interface for backward compatibility
 */
export interface Logger {
    debug: (message: string, ...args: unknown[]) => void;
    info: (message: string, ...args: unknown[]) => void;
    warn: (message: string, ...args: unknown[]) => void;
    error: (message: string, ...args: unknown[]) => void;
}
/**
 * Create a logger instance with the specified log level
 */
export declare function createLogger(level?: LogLevel): Logger;
/**
 * Console Logger Implementation for MCP Protocol
 *
 * Logs messages to stderr with timestamp and level formatting.
 * Respects the configured minimum log level.
 * Implements the MCPLogger interface for protocol compliance.
 */
export declare class ConsoleLogger implements MCPLogger {
    private readonly minLevel;
    private readonly minPriority;
    private readonly prefix;
    constructor(minLevel?: MCPLogLevel, prefix?: string);
    /**
     * Check if a log level should be output
     */
    private shouldLog;
    /**
     * Format a log message
     */
    private formatMessage;
    /**
     * Write a log message to stderr
     */
    private writeLog;
    debug(message: string, data?: unknown): void;
    info(message: string, data?: unknown): void;
    notice(message: string, data?: unknown): void;
    warning(message: string, data?: unknown): void;
    error(message: string, data?: unknown): void;
    critical(message: string, data?: unknown): void;
    alert(message: string, data?: unknown): void;
    emergency(message: string, data?: unknown): void;
}
/**
 * JSON Logger Implementation
 *
 * Outputs structured JSON logs to stderr, suitable for log aggregation systems.
 */
export declare class JsonLogger implements MCPLogger {
    private readonly minLevel;
    private readonly minPriority;
    private readonly metadata;
    constructor(minLevel?: MCPLogLevel, metadata?: Record<string, unknown>);
    private shouldLog;
    private writeLog;
    debug(message: string, data?: unknown): void;
    info(message: string, data?: unknown): void;
    notice(message: string, data?: unknown): void;
    warning(message: string, data?: unknown): void;
    error(message: string, data?: unknown): void;
    critical(message: string, data?: unknown): void;
    alert(message: string, data?: unknown): void;
    emergency(message: string, data?: unknown): void;
}
/**
 * Silent Logger Implementation
 *
 * No-op logger that discards all messages. Useful for testing.
 */
export declare class SilentLogger implements MCPLogger {
    debug(): void;
    info(): void;
    notice(): void;
    warning(): void;
    error(): void;
    critical(): void;
    alert(): void;
    emergency(): void;
}
/**
 * Create an MCP-compatible logger based on configuration
 */
export declare function createMCPLogger(level?: MCPLogLevel, format?: 'text' | 'json', metadata?: Record<string, unknown>): MCPLogger;
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