import type { CallToolResult } from '@modelcontextprotocol/sdk/types.js';
import { FetchError, isAbortError, isSystemError } from './errors.js';
/* -------------------------------------------------------------------------------------------------
* Tool error mapping
* ------------------------------------------------------------------------------------------------- */
type ToolErrorResponse = CallToolResult & {
isError: true;
};
export function createToolErrorResponse(
message: string,
url: string,
extra?: {
code?: string;
statusCode?: number;
details?: Record<string, unknown>;
}
): ToolErrorResponse {
const errorContent: Record<string, unknown> = {
error: message,
...(extra?.code ? { code: extra.code } : {}),
url,
...(extra?.statusCode !== undefined
? { statusCode: extra.statusCode }
: {}),
...(extra?.details ? { details: extra.details } : {}),
};
return {
content: [{ type: 'text', text: JSON.stringify(errorContent) }],
isError: true,
};
}
function isValidationError(error: unknown): error is NodeJS.ErrnoException {
return (
error instanceof Error &&
isSystemError(error) &&
error.code === 'VALIDATION_ERROR'
);
}
function isHandledToolError(
error: unknown
): error is FetchError | NodeJS.ErrnoException {
return error instanceof FetchError || isValidationError(error);
}
function resolveToolErrorMessage(
error: unknown,
fallbackMessage: string
): string {
if (isHandledToolError(error)) {
return error.message;
}
if (error instanceof Error) {
return `${fallbackMessage}: ${error.message}`;
}
return `${fallbackMessage}: Unknown error`;
}
function resolveToolErrorCode(error: unknown): string {
if (error instanceof FetchError) return error.code;
if (isValidationError(error)) return 'VALIDATION_ERROR';
if (isAbortError(error)) return 'ABORTED';
return 'FETCH_ERROR';
}
export function handleToolError(
error: unknown,
url: string,
fallbackMessage = 'Operation failed'
): ToolErrorResponse {
const message = resolveToolErrorMessage(error, fallbackMessage);
const code = resolveToolErrorCode(error);
if (error instanceof FetchError) {
return createToolErrorResponse(message, url, {
code,
statusCode: error.statusCode,
details: error.details,
});
}
return createToolErrorResponse(message, url, { code });
}
