fix(Call n8n Sub-Workflow Tool Node): Fix json type when using $fromAI (#13102)

packages/core/src/execution-engine/node-execution-context/utils/__tests__/create-node-as-tool.test.ts

@@ -319,7 +319,7 @@ describe('createNodeAsTool', () => {
 
 			const tool = createNodeAsTool(options).response;
 
-			expect(tool.schema.shape.complexJson._def.innerType).toBeInstanceOf(z.ZodRecord);
+			expect(tool.schema.shape.complexJson._def.innerType).toBeInstanceOf(z.ZodEffects);
 			expect(tool.schema.shape.complexJson.description).toBe('Param with complex JSON default');
 			expect(tool.schema.shape.complexJson._def.defaultValue()).toEqual({
 				nested: { key: 'value' },

packages/workflow/src/FromAIParseUtils.ts

@@ -34,9 +34,61 @@ export function generateZodSchema(placeholder: FromAIArgument): z.ZodTypeAny {
 		case 'boolean':
 			schema = z.boolean();
 			break;
-		case 'json':
+		case 'json': {
-			schema = z.record(z.any());
+			interface CustomSchemaDef extends z.ZodTypeDef {
+				jsonSchema?: {
+					anyOf: [
+						{
+							type: 'object';
+							minProperties: number;
+							additionalProperties: boolean;
+						},
+						{
+							type: 'array';
+							minItems: number;
+						},
+					];
+				};
+			}
+
+			// Create a custom schema to validate that the incoming data is either a non-empty object or a non-empty array.
+			const customSchema = z.custom<Record<string, unknown> | unknown[]>(
+				(data: unknown) => {
+					if (data === null || typeof data !== 'object') return false;
+					if (Array.isArray(data)) {
+						return data.length > 0;
+					}
+					return Object.keys(data).length > 0;
+				},
+				{
+					message: 'Value must be a non-empty object or a non-empty array',
+				},
+			);
+
+			// Cast the custom schema to a type that includes our JSON metadata.
+			const typedSchema = customSchema as z.ZodType<
+				Record<string, unknown> | unknown[],
+				CustomSchemaDef
+			>;
+
+			// Attach the updated `jsonSchema` metadata to the internal definition.
+			typedSchema._def.jsonSchema = {
+				anyOf: [
+					{
+						type: 'object',
+						minProperties: 1,
+						additionalProperties: true,
+					},
+					{
+						type: 'array',
+						minItems: 1,
+					},
+				],
+			};
+
+			schema = typedSchema;
 			break;
+		}
 		default:
 			schema = z.string();
 	}

packages/workflow/test/FromAIParseUtils.test.ts

@@ -1,7 +1,8 @@
 import {
 	extractFromAICalls,
-	type FromAIArgument,
 	traverseNodeParameters,
+	type FromAIArgument,
+	generateZodSchema,
 } from '@/FromAIParseUtils';
 
 // Note that for historic reasons a lot of testing of this file happens indirectly in `packages/core/test/CreateNodeAsTool.test.ts`
@@ -85,3 +86,61 @@ describe('traverseNodeParameters', () => {
 		},
 	);
 });
+
+describe('JSON Type Parsing via generateZodSchema', () => {
+	it('should correctly parse a JSON parameter without default', () => {
+		// Use an actual $fromAI call string via extractFromAICalls:
+		const [arg] = extractFromAICalls(
+			'$fromAI("jsonWithoutDefault", "JSON parameter without default", "json")',
+		);
+		const schema = generateZodSchema(arg);
+
+		// Valid non-empty JSON objects should pass.
+		expect(() => schema.parse({ key: 'value' })).not.toThrow();
+		expect(schema.parse({ key: 'value' })).toEqual({ key: 'value' });
+
+		// Parsing an empty object should throw a validation error.
+		expect(() => schema.parse({})).toThrowError(
+			/Value must be a non-empty object or a non-empty array/,
+		);
+	});
+
+	it('should correctly parse a JSON parameter with a valid default', () => {
+		const [arg] = extractFromAICalls(
+			'$fromAI("jsonWithValidDefault", "JSON parameter with valid default", "json", "{"key": "defaultValue"}")',
+		);
+		const schema = generateZodSchema(arg);
+
+		// The default value is now stored as a parsed object.
+		expect(schema._def.defaultValue()).toEqual({ key: 'defaultValue' });
+	});
+
+	it('should parse a JSON parameter with an empty default', () => {
+		const [arg] = extractFromAICalls(
+			'$fromAI("jsonEmptyDefault", "JSON parameter with empty default", "json", "{}")',
+		);
+		const schema = generateZodSchema(arg);
+
+		// The default value is stored as an empty object.
+		expect(schema._def.defaultValue()).toEqual({});
+
+		// Parsing an empty object should throw a validation error.
+		expect(() => schema.parse({})).toThrowError(
+			/Value must be a non-empty object or a non-empty array/,
+		);
+	});
+
+	it('should use provided JSON value over the default value', () => {
+		const [arg] = extractFromAICalls(
+			'$fromAI("jsonParamCustom", "JSON parameter with custom default", "json", "{"initial": "value"}")',
+		);
+		const schema = generateZodSchema(arg);
+
+		// Check that the stored default value parses to the expected object.
+		expect(schema._def.defaultValue()).toEqual({ initial: 'value' });
+
+		// When a new valid value is provided, the schema should use it.
+		const newValue = { newKey: 'newValue' };
+		expect(schema.parse(newValue)).toEqual(newValue);
+	});
+});