import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { LoggingLevel } from "@modelcontextprotocol/sdk/types.js";
const LOG_LEVELS: LoggingLevel[] = [
"debug", "info", "notice", "warning", "error", "critical", "alert", "emergency"
];
export class Logger {
private server: Server;
private minLevel: LoggingLevel = "info";
constructor(server: Server) {
this.server = server;
}
setLevel(level: LoggingLevel): void {
this.minLevel = level;
}
getLevel(): LoggingLevel {
return this.minLevel;
}
private shouldLog(level: LoggingLevel): boolean {
return LOG_LEVELS.indexOf(level) >= LOG_LEVELS.indexOf(this.minLevel);
}
private log(level: LoggingLevel, logger: string, data: unknown): void {
if (!this.shouldLog(level)) return;
// sendLoggingMessage is async — use .catch() to handle pre-handshake calls gracefully
this.server.sendLoggingMessage({ level, logger, data }).catch(() => {
// Connection may not be established yet; fall back to stderr
console.error(`[${level}] [${logger}]`, data);
});
}
debug(logger: string, data: unknown): void {
this.log("debug", logger, data);
}
info(logger: string, data: unknown): void {
this.log("info", logger, data);
}
notice(logger: string, data: unknown): void {
this.log("notice", logger, data);
}
warning(logger: string, data: unknown): void {
this.log("warning", logger, data);
}
error(logger: string, data: unknown): void {
this.log("error", logger, data);
}
}
