fix(AI Agent Node): Throw better errors for non-tool agents when using structured tools (#11582)

packages/@n8n/nodes-langchain/nodes/agents/Agent/test/utils.test.ts

@@ -0,0 +1,106 @@
+import type { Tool } from 'langchain/tools';
+import { DynamicStructuredTool } from 'langchain/tools';
+import { NodeOperationError } from 'n8n-workflow';
+import type { INode } from 'n8n-workflow';
+import { z } from 'zod';
+
+import { checkForStructuredTools } from '../agents/utils';
+
+describe('checkForStructuredTools', () => {
+	let mockNode: INode;
+
+	beforeEach(() => {
+		mockNode = {
+			id: 'test-node',
+			name: 'Test Node',
+			type: 'test',
+			typeVersion: 1,
+			position: [0, 0],
+			parameters: {},
+		};
+	});
+
+	it('should not throw error when no DynamicStructuredTools are present', async () => {
+		const tools = [
+			{
+				name: 'regular-tool',
+				constructor: { name: 'Tool' },
+			} as Tool,
+		];
+
+		await expect(
+			checkForStructuredTools(tools, mockNode, 'Conversation Agent'),
+		).resolves.not.toThrow();
+	});
+
+	it('should throw NodeOperationError when DynamicStructuredTools are present', async () => {
+		const dynamicTool = new DynamicStructuredTool({
+			name: 'dynamic-tool',
+			description: 'test tool',
+			schema: z.object({}),
+			func: async () => 'result',
+		});
+
+		const tools: Array<Tool | DynamicStructuredTool> = [dynamicTool];
+
+		await expect(checkForStructuredTools(tools, mockNode, 'Conversation Agent')).rejects.toThrow(
+			NodeOperationError,
+		);
+
+		await expect(
+			checkForStructuredTools(tools, mockNode, 'Conversation Agent'),
+		).rejects.toMatchObject({
+			message:
+				'The selected tools are not supported by "Conversation Agent", please use "Tools Agent" instead',
+			description: 'Incompatible connected tools: "dynamic-tool"',
+		});
+	});
+
+	it('should list multiple dynamic tools in error message', async () => {
+		const dynamicTool1 = new DynamicStructuredTool({
+			name: 'dynamic-tool-1',
+			description: 'test tool 1',
+			schema: z.object({}),
+			func: async () => 'result',
+		});
+
+		const dynamicTool2 = new DynamicStructuredTool({
+			name: 'dynamic-tool-2',
+			description: 'test tool 2',
+			schema: z.object({}),
+			func: async () => 'result',
+		});
+
+		const tools = [dynamicTool1, dynamicTool2];
+
+		await expect(
+			checkForStructuredTools(tools, mockNode, 'Conversation Agent'),
+		).rejects.toMatchObject({
+			description: 'Incompatible connected tools: "dynamic-tool-1", "dynamic-tool-2"',
+		});
+	});
+
+	it('should throw error with mixed tool types and list only dynamic tools in error message', async () => {
+		const regularTool = {
+			name: 'regular-tool',
+			constructor: { name: 'Tool' },
+		} as Tool;
+
+		const dynamicTool = new DynamicStructuredTool({
+			name: 'dynamic-tool',
+			description: 'test tool',
+			schema: z.object({}),
+			func: async () => 'result',
+		});
+
+		const tools = [regularTool, dynamicTool];
+
+		await expect(
+			checkForStructuredTools(tools, mockNode, 'Conversation Agent'),
+		).rejects.toMatchObject({
+			message:
+				'The selected tools are not supported by "Conversation Agent", please use "Tools Agent" instead',
+			description: 'Incompatible connected tools: "dynamic-tool"',
+		});
+	});
+});