/**
* MCP-compatible logger that writes ALL output to stderr.
* This is critical because stdout is reserved for JSON-RPC communication
* in the MCP stdio transport.
*
* Replaced winston with direct console.error to guarantee stderr usage.
*/
export const logger = {
info: (message: string, meta?: any) => log('info', message, meta),
error: (message: string, meta?: any) => log('error', message, meta),
warn: (message: string, meta?: any) => log('warn', message, meta),
debug: (message: string, meta?: any) => log('debug', message, meta),
level: process.env.LOG_LEVEL || 'error'
};
const levels: Record<string, number> = {
debug: 0,
info: 1,
warn: 2,
error: 3
};
function log(level: string, message: string, meta?: any) {
const currentLevelScore = levels[logger.level] ?? 3; // Default to error
const messageLevelScore = levels[level] ?? 1;
if (messageLevelScore < currentLevelScore) return;
const timestamp = new Date().toISOString();
const logData = {
level,
message,
timestamp,
...meta
};
// Explicitly write to stderr to avoid corrupting stdout
process.stderr.write(JSON.stringify(logData) + '\n');
}
export const setLogLevel = (level: string) => {
logger.level = level;
};
