n8n-io/n8n · error · Error

Cannot combine `--langsmith` with `--backend local`

Error message

Cannot combine `--langsmith` with `--backend local`

What it means

Error "Cannot combine `--langsmith` with `--backend local`" thrown in n8n-io/n8n.

Source

Thrown at packages/@n8n/ai-workflow-builder.ee/evaluations/cli/argument-parser.ts:519

	if (args.technique && !filters.technique) filters.technique = args.technique;

	const hasAny = Object.values(filters).some((v) => typeof v === 'string' && v.length > 0);
	return hasAny ? filters : undefined;
}

export function parseEvaluationArgs(argv: string[] = process.argv.slice(2)): EvaluationArgs {
	// Check for help flag before parsing
	if (argv.includes('--help') || argv.includes('-h')) {
		printHelp();
		process.exit(0);
	}

	const { values, seenKeys } = parseCli(argv);

	if (values.langsmith === true) {
		const backendWasExplicit = seenKeys.has('backend');
		if (backendWasExplicit && values.backend !== 'langsmith') {
			throw new Error('Cannot combine `--langsmith` with `--backend local`');
		}
		values.backend = 'langsmith';
	}

	const parsed = cliSchema.parse(values);

	const featureFlags = parseFeatureFlags({
		suite: parsed.suite,
	});

	const filters = parseFilters({
		filter: parsed.filter,
		notionId: parsed.notionId,
		technique: parsed.technique,
	});

	if (parsed.suite !== 'pairwise' && (filters?.doSearch || filters?.dontSearch)) {
		throw new Error(

View on GitHub (pinned to 5ac6606e81)

When it happens

Trigger: Thrown at packages/@n8n/ai-workflow-builder.ee/evaluations/cli/argument-parser.ts:519 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/6d1564d30d0d49ef. Report an issue: GitHub.