export class MCPError extends Error {
constructor(
message: string,
public readonly code: string,
public readonly details?: any
) {
super(message);
this.name = 'MCPError';
}
}
export class ConnectionError extends MCPError {
constructor(message: string, details?: any) {
super(message, 'CONNECTION_ERROR', details);
this.name = 'ConnectionError';
}
}
export class ValidationError extends MCPError {
constructor(message: string, details?: any) {
super(message, 'VALIDATION_ERROR', details);
this.name = 'ValidationError';
}
}
export class SecurityError extends MCPError {
constructor(message: string, details?: any) {
super(message, 'SECURITY_ERROR', details);
this.name = 'SecurityError';
}
}
export class QueryError extends MCPError {
constructor(message: string, details?: any) {
super(message, 'QUERY_ERROR', details);
this.name = 'QueryError';
}
}
export class TimeoutError extends MCPError {
constructor(message: string, details?: any) {
super(message, 'TIMEOUT_ERROR', details);
this.name = 'TimeoutError';
}
}
export class PermissionError extends MCPError {
constructor(message: string, details?: any) {
super(message, 'PERMISSION_ERROR', details);
this.name = 'PermissionError';
}
}
export class ErrorHandler {
static handleSqlServerError(error: any): MCPError {
if (!error) {
return new MCPError('Unknown database error occurred', 'UNKNOWN_ERROR');
}
const message = error.message || error.toString();
const code = error.code || error.number;
// SQL Server specific error handling
if (typeof code === 'number') {
switch (code) {
case 18456: // Login failed
return new ConnectionError(
'Authentication failed: Invalid username or password',
{ originalError: message, code }
);
case 2: // Server not found
case 53: // Network path not found
return new ConnectionError(
'Connection failed: Server not found or not accessible',
{ originalError: message, code }
);
case -2: // Timeout
return new TimeoutError(
'Connection timeout: Server took too long to respond',
{ originalError: message, code }
);
case 208: // Invalid object name
return new ValidationError(
'Invalid table or object name specified',
{ originalError: message, code }
);
case 207: // Invalid column name
return new ValidationError(
'Invalid column name specified',
{ originalError: message, code }
);
case 262: // Permission denied
case 229: // SELECT permission denied
return new PermissionError(
'Permission denied: Insufficient privileges to access this resource',
{ originalError: message, code }
);
case 1205: // Deadlock
return new QueryError(
'Query failed due to deadlock - please retry',
{ originalError: message, code }
);
case 8152: // String truncation
return new ValidationError(
'Data too long for target column',
{ originalError: message, code }
);
case 515: // Cannot insert null
return new ValidationError(
'Cannot insert null value into non-nullable column',
{ originalError: message, code }
);
default:
// Generic SQL Server error
return new QueryError(
`Database error (${code}): ${message}`,
{ originalError: message, code }
);
}
}
// Handle connection-specific errors by message content
if (message.toLowerCase().includes('login failed')) {
return new ConnectionError(
'Authentication failed: Invalid username or password',
{ originalError: message }
);
}
if (message.toLowerCase().includes('server was not found') ||
message.toLowerCase().includes('network-related')) {
return new ConnectionError(
'Connection failed: Server not found or network issue',
{ originalError: message }
);
}
if (message.toLowerCase().includes('timeout')) {
return new TimeoutError(
'Operation timed out',
{ originalError: message }
);
}
if (message.toLowerCase().includes('ssl') ||
message.toLowerCase().includes('certificate')) {
return new ConnectionError(
'SSL/Certificate error: Check encryption and certificate trust settings',
{ originalError: message }
);
}
if (message.toLowerCase().includes('permission') ||
message.toLowerCase().includes('denied')) {
return new PermissionError(
'Permission denied: Insufficient database privileges',
{ originalError: message }
);
}
// Default to generic query error
return new QueryError(
`Database operation failed: ${message}`,
{ originalError: message }
);
}
static formatErrorForUser(error: MCPError): {
error: string;
code: string;
suggestions?: string[];
} {
const result = {
error: error.message,
code: error.code,
suggestions: [] as string[],
};
// Add helpful suggestions based on error type
switch (error.code) {
case 'CONNECTION_ERROR':
result.suggestions = [
'Verify server hostname and port number',
'Check if SQL Server service is running',
'Ensure network connectivity to the server',
'Verify firewall settings allow SQL Server connections',
];
break;
case 'VALIDATION_ERROR':
result.suggestions = [
'Check spelling of table and column names',
'Verify the object exists in the specified schema',
'Ensure you have the correct database selected',
];
break;
case 'SECURITY_ERROR':
result.suggestions = [
'Only read-only SELECT queries are allowed',
'Remove any INSERT, UPDATE, DELETE, or DDL statements',
'Check for potentially dangerous keywords in your query',
];
break;
case 'PERMISSION_ERROR':
result.suggestions = [
'Contact your database administrator for access',
'Verify you have SELECT permissions on the target tables',
'Check if you need access to specific schemas or databases',
];
break;
case 'TIMEOUT_ERROR':
result.suggestions = [
'Try a simpler query with fewer rows',
'Add WHERE clauses to limit the result set',
'Check if the server is under heavy load',
];
break;
case 'QUERY_ERROR':
result.suggestions = [
'Check your SQL syntax',
'Verify all referenced tables and columns exist',
'Try breaking complex queries into simpler parts',
];
break;
}
return result;
}
}
