n8n-io/n8n · error · NodeOperationError

The provided workflow is not valid JSON: "${(error as Error)

Error message

The provided workflow is not valid JSON: "${(error as Error).message}"

What it means

Thrown by the Call Workflow Tool v1 when 'Source' is 'Parameter' and the supplied workflowJson string fails JSON.parse. The tool tries to load a sub-workflow definition inline from the parameter, and an unparseable definition cannot be executed.

Source

Thrown at packages/@n8n/nodes-langchain/nodes/tools/ToolWorkflow/v1/ToolWorkflowV1.node.ts:81

					const { value } = this.getNodeParameter(
						'workflowId',
						itemIndex,
						{},
					) as INodeParameterResourceLocator;
					workflowInfo.id = value as string;
				}

				subWorkflowId = workflowInfo.id;
			} else if (source === 'parameter') {
				// Read workflow from parameter
				const workflowJson = this.getNodeParameter('workflowJson', itemIndex) as string;
				try {
					workflowInfo.code = JSON.parse(workflowJson) as IWorkflowBase;

					// subworkflow is same as parent workflow
					subWorkflowId = workflowProxy.$workflow.id;
				} catch (error) {
					throw new NodeOperationError(
						this.getNode(),
						`The provided workflow is not valid JSON: "${(error as Error).message}"`,
						{
							itemIndex,
						},
					);
				}
			}

			const rawData: IDataObject = { query };

			const workflowFieldsJson = this.getNodeParameter('fields.values', itemIndex, [], {
				rawExpressions: true,
			}) as SetField[];

			// Copied from Set Node v2
			for (const entry of workflowFieldsJson) {
				if (entry.type === 'objectValue' && (entry.objectValue as string).startsWith('=')) {

View on GitHub (pinned to 5ac6606e81)

Solutions

1. Re-export the target workflow from n8n (⋯ → Download) and paste the full, unedited JSON.
2. Paste the workflowJson value into a JSON linter and fix the reported syntax error.
3. Switch 'Source' from 'Parameter' to 'Database' and select the workflow by ID instead.

Example fix

// before: workflowJson = '{ "nodes": [ ' (truncated)
// after: re-download and paste the complete workflow JSON,
// or set Source = 'Database' and pick the workflow by ID.

const workflowJson = this.getNodeParameter('workflowJson', itemIndex) as string;
try { JSON.parse(workflowJson); }
catch (e) { throw new Error(`workflowJson is not valid JSON: ${e.message}`); }

function isParsableWorkflowJson(s: string): boolean {
  try { JSON.parse(s); return true; } catch { return false; }
}

try { workflowInfo.code = JSON.parse(workflowJson); }
catch (error) { /* show fix-JSON guidance to user */ }

When it happens

Trigger: Pasting a workflow export whose JSON is malformed (truncated, edited by hand, contains expression syntax that breaks parsing); copying only part of a workflow JSON.

Common situations: Manually editing the workflow JSON parameter; pasting from a source that introduced smart quotes or stripped braces; truncation when copying a large workflow.

Related errors

• The provided workflow is not valid JSON: "${(error as Error)
• Could not replace placeholders in ${key}: ${error.message}
• Error during parsing of JSON Schema. ${error}
• Failed to read prebuilt-workflows manifest at ${path}: ${msg
• Additional Model Request Fields must be valid JSON

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/d29e0f2e8f22cba8. Report an issue: GitHub.