import { config } from './config.js';
export type LogLevel = 'error' | 'warn' | 'info' | 'debug';
const levels: Record<LogLevel, number> = {
error: 0,
warn: 1,
info: 2,
debug: 3,
};
const currentLevel = ((): LogLevel => {
const level = config.logLevel as LogLevel;
return level in levels ? level : 'info';
})();
const shouldLog = (level: LogLevel): boolean => {
return levels[level] <= levels[currentLevel];
};
const formatMessage = (level: LogLevel, message: string, meta?: Record<string, unknown>): string => {
const timestamp = new Date().toISOString();
if (config.logFormat === 'json') {
return JSON.stringify({
timestamp,
level,
message,
...(meta ? { meta } : {}),
});
}
const metaString = meta ? ` ${JSON.stringify(meta)}` : '';
return `[${timestamp}] [${level.toUpperCase()}] ${message}${metaString}`;
};
const log = (level: LogLevel, message: string, meta?: Record<string, unknown>): void => {
if (!shouldLog(level)) return;
const output = formatMessage(level, message, meta);
// Always log to stderr to avoid polluting stdio MCP responses.
console.error(output);
};
export const logger = {
error: (message: string, meta?: Record<string, unknown>) => log('error', message, meta),
warn: (message: string, meta?: Record<string, unknown>) => log('warn', message, meta),
info: (message: string, meta?: Record<string, unknown>) => log('info', message, meta),
debug: (message: string, meta?: Record<string, unknown>) => log('debug', message, meta),
};
