Master MCP Server

/** * Standardized error types and helpers. */ export type ErrorSeverity = 'fatal' | 'error' | 'warn' export interface SerializedError { name: string message: string code?: string status?: number severity?: ErrorSeverity details?: unknown stack?: string cause?: SerializedError } export class AppError extends Error { code?: string status?: number severity: ErrorSeverity details?: unknown override cause?: unknown constructor(message: string, opts?: { code?: string; status?: number; severity?: ErrorSeverity; details?: unknown; cause?: unknown }) { super(message) this.name = this.constructor.name this.code = opts?.code this.status = opts?.status this.severity = opts?.severity ?? 'error' this.details = opts?.details this.cause = opts?.cause } toJSON(): SerializedError { return serializeError(this) } } export class ValidationError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'VALIDATION_ERROR', status: 400, details, severity: 'warn' }) } } export class AuthError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'AUTH_ERROR', status: 401, details }) } } export class PermissionError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'FORBIDDEN', status: 403, details }) } } export class NotFoundError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'NOT_FOUND', status: 404, details, severity: 'warn' }) } } export class RateLimitError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'RATE_LIMITED', status: 429, details, severity: 'warn' }) } } export class ExternalServiceError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'EXTERNAL_SERVICE_ERROR', status: 502, details }) } } export class CircuitBreakerError extends AppError { constructor(message: string, details?: unknown) { super(message, { code: 'CIRCUIT_OPEN', status: 503, details }) } } export function serializeError(err: unknown): SerializedError { if (err instanceof AppError) { return { name: err.name, message: err.message, code: err.code, status: err.status, severity: err.severity, details: err.details, stack: err.stack, cause: err.cause ? serializeError(err.cause as any) : undefined, } } if (err instanceof Error) { return { name: err.name, message: err.message, stack: err.stack, } } return { name: 'Error', message: String(err) } } export function deserializeError(obj: SerializedError): AppError { const err = new AppError(obj.message, { code: obj.code, status: obj.status, severity: obj.severity, details: obj.details, cause: obj.cause ? deserializeError(obj.cause) : undefined, }) err.name = obj.name err.stack = obj.stack return err } export function withErrorContext<T>(fn: () => Promise<T>, context: Record<string, unknown>): Promise<T> { return fn().catch((e) => { if (e instanceof AppError) throw new AppError(e.message, { ...e, details: { ...(e.details as any), ...context } }) const err = new AppError('Unhandled error', { code: 'UNHANDLED', details: { cause: serializeError(e), ...context } }) throw err }) } export function stackTrace(e?: Error): string { const err = e ?? new Error('stack') return err.stack || '' } export function isAppError(e: unknown): e is AppError { return e instanceof AppError }