n8n-io/n8n · error · Error

Failed to parse CSV file

Error message

Failed to parse CSV file: ${message}

What it means

Wrapper error from parseCsv in the CSV prompt loader. It fires when the csv-parse library throws while parsing the file content (malformed quoting, unexpected structure), and re-raises with the underlying parser message appended. The parser runs with relaxed settings (skip empty lines, relax column count), so this indicates real structural corruption rather than ordinary variation.

Solutions

1. Fix the CSV syntax problem named in the wrapped message (unclosed quotes, inconsistent columns, bad encoding).
2. Re-export the CSV with standard quoting (RFC 4180) and UTF-8 encoding.
3. Validate the file with a CSV linter or open it in a spreadsheet tool to spot malformed rows.

When it happens

Trigger: Thrown at packages/@n8n/ai-workflow-builder.ee/evaluations/cli/csv-prompt-loader.ts:38 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/d7ce7570d430d82c. Report an issue: GitHub.

Appendix: source

Thrown at packages/@n8n/ai-workflow-builder.ee/evaluations/cli/csv-prompt-loader.ts:38

}

function sanitizeValue(value: string | undefined) {
	return value?.trim() ?? '';
}

function parseCsv(content: string): ParsedCsvRow[] {
	try {
		const rows = parse(content.replace(/^\ufeff/, ''), {
			columns: false,
			skip_empty_lines: true,
			trim: true,
			relax_column_count: true,
		}) as ParsedCsvRow[];

		return rows.map((row) => row.map((cell) => cell ?? ''));
	} catch (error) {
		const message = error instanceof Error ? error.message : 'Unknown parsing error';
		throw new Error(`Failed to parse CSV file: ${message}`);
	}
}

export function loadTestCasesFromCsv(csvPath: string): TestCase[] {
	const resolvedPath = isAbsolute(csvPath) ? csvPath : resolve(process.cwd(), csvPath);

	if (!existsSync(resolvedPath)) {
		throw new Error(`CSV file not found at ${resolvedPath}`);
	}

	const rows = parseCsv(readFileSync(resolvedPath, 'utf8'));

	if (rows.length === 0) {
		throw new Error('The provided CSV file is empty');
	}

	const hasHeader = isHeaderRow(rows[0]);
	const header = hasHeader ? rows[0] : undefined;

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