n8n-io/n8n · error · LLMServiceError

LLM doesn't support withStructuredOutput

Error message

LLM doesn't support withStructuredOutput

What it means

Error "LLM doesn't support withStructuredOutput" thrown in n8n-io/n8n.

Source

Thrown at packages/@n8n/ai-workflow-builder.ee/src/chains/parameter-updater.ts:76

Current Parameters: {current_parameters}
</selected_node>

<requested_changes>
{changes}
</requested_changes>

Based on the requested changes and the node's property definitions, return the complete updated parameters object.`;

/**
 * Creates a parameter updater chain with dynamic prompt building
 */
export const createParameterUpdaterChain = (
	llm: BaseChatModel,
	options: ParameterUpdaterOptions,
	logger?: Logger,
) => {
	if (typeof llm.withStructuredOutput !== 'function') {
		throw new LLMServiceError("LLM doesn't support withStructuredOutput", {
			llmModel: llm._llmType(),
		});
	}

	// Build context for registry lookups
	const context = {
		nodeType: options.nodeType,
		nodeDefinition: options.nodeDefinition,
		requestedChanges: options.requestedChanges,
		hasResourceLocatorParams: hasResourceLocatorParameters(options.nodeDefinition),
	};

	// Get matching guides and examples from registry
	const guides = getMatchingGuides(context);
	const examples = getMatchingExamples(context);

	// Build dynamic system prompt using PromptBuilder
	const builder = createPromptBuilder()

View on GitHub (pinned to 5ac6606e81)

When it happens

Trigger: Thrown at packages/@n8n/ai-workflow-builder.ee/src/chains/parameter-updater.ts:76 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/54c3de22131a0059. Report an issue: GitHub.