export interface ErrorResponse {
[key: string]: unknown;
content: { type: 'text'; text: string }[];
structuredContent: {
ok: false;
error: { code: string; message: string };
result?: unknown;
};
isError: true;
}
function getMessageFromErrorInstance(error: unknown): string | undefined {
if (error instanceof Error && error.message) {
return error.message;
}
return undefined;
}
function getMessageFromString(error: unknown): string | undefined {
if (typeof error === 'string' && error.length > 0) {
return error;
}
return undefined;
}
function isNonEmptyString(value: unknown): value is string {
return typeof value === 'string' && value.length > 0;
}
function isObjectWithMessage(value: unknown): value is { message?: unknown } {
return typeof value === 'object' && value !== null && 'message' in value;
}
function getMessageFromObject(error: unknown): string | undefined {
if (!isObjectWithMessage(error)) {
return undefined;
}
const message = error.message;
return isNonEmptyString(message) ? message : undefined;
}
export function getErrorMessage(error: unknown): string {
return (
getMessageFromErrorInstance(error) ??
getMessageFromString(error) ??
getMessageFromObject(error) ??
'Unknown error'
);
}
export function createErrorResponse(
code: string,
message: string,
result?: unknown
): ErrorResponse {
const structured: ErrorResponse['structuredContent'] = {
ok: false,
error: { code, message },
...(result === undefined ? {} : { result }),
};
return {
content: [{ type: 'text' as const, text: JSON.stringify(structured) }],
structuredContent: structured,
isError: true as const,
};
}
