fix(AI Agent Node): Fix tool calling when tools run in a loop (#15250)

Co-authored-by: JP van Oosten <jp@n8n.io>
Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/@n8n/nodes-langchain/nodes/tools/ToolWorkflow/v2/ToolWorkflowV2.node.ts

@@ -39,6 +39,7 @@ export class ToolWorkflowV2 implements INodeType {
 		const description = this.getNodeParameter('description', itemIndex) as string;
 
 		const tool = await workflowToolService.createTool({
+			ctx: this,
 			name,
 			description,
 			itemIndex,

packages/@n8n/nodes-langchain/nodes/tools/ToolWorkflow/v2/ToolWorkflowV2.test.ts

@@ -13,6 +13,10 @@ import { WorkflowToolService } from './utils/WorkflowToolService';
 
 // Mock ISupplyDataFunctions interface
 function createMockContext(overrides?: Partial<ISupplyDataFunctions>): ISupplyDataFunctions {
+	let runIndex = 0;
+	const getNextRunIndex = jest.fn(() => {
+		return runIndex++;
+	});
 	return {
 		runIndex: 0,
 		getNodeParameter: jest.fn(),
@@ -26,6 +30,7 @@ function createMockContext(overrides?: Partial<ISupplyDataFunctions>): ISupplyDa
 		getInputData: jest.fn(),
 		getMode: jest.fn(),
 		getRestApiUrl: jest.fn(),
+		getNextRunIndex,
 		getTimezone: jest.fn(),
 		getWorkflow: jest.fn(),
 		getWorkflowStaticData: jest.fn(),
@@ -56,6 +61,7 @@ describe('WorkflowTool::WorkflowToolService', () => {
 	describe('createTool', () => {
 		it('should create a basic dynamic tool when schema is not used', async () => {
 			const toolParams = {
+				ctx: context,
 				name: 'TestTool',
 				description: 'Test Description',
 				itemIndex: 0,
@@ -70,6 +76,7 @@ describe('WorkflowTool::WorkflowToolService', () => {
 
 		it('should create a tool that can handle successful execution', async () => {
 			const toolParams = {
+				ctx: context,
 				name: 'TestTool',
 				description: 'Test Description',
 				itemIndex: 0,
@@ -112,6 +119,7 @@ describe('WorkflowTool::WorkflowToolService', () => {
 
 		it('should handle errors during tool execution', async () => {
 			const toolParams = {
+				ctx: context,
 				name: 'TestTool',
 				description: 'Test Description',
 				itemIndex: 0,

packages/@n8n/nodes-langchain/nodes/tools/ToolWorkflow/v2/utils/WorkflowToolService.ts

@@ -60,17 +60,21 @@ export class WorkflowToolService {
 
 	// Creates the tool based on the provided parameters
 	async createTool({
+		ctx,
 		name,
 		description,
 		itemIndex,
 	}: {
+		ctx: ISupplyDataFunctions;
 		name: string;
 		description: string;
 		itemIndex: number;
 	}): Promise<DynamicTool | DynamicStructuredTool> {
-		let runIndex = 0;
 		// Handler for the tool execution, will be called when the tool is executed
 		// This function will execute the sub-workflow and return the response
+		// We get the runIndex from the context to handle multiple executions
+		// of the same tool when the tool is used in a loop or in a parallel execution.
+		let runIndex: number = ctx.getNextRunIndex();
 		const toolHandler = async (
 			query: string | IDataObject,
 			runManager?: CallbackManagerForToolRun,

packages/core/src/execution-engine/node-execution-context/__tests__/supply-data-context.test.ts

@@ -15,6 +15,7 @@ import type {
 	ICredentialDataDecryptedObject,
 	NodeConnectionType,
 } from 'n8n-workflow';
+import type { IRunData } from 'n8n-workflow';
 import { ApplicationError, NodeConnectionTypes } from 'n8n-workflow';
 
 import { describeCommonTests } from './shared-tests';
@@ -186,4 +187,36 @@ describe('SupplyDataContext', () => {
 			expect(clone).not.toBe(supplyDataContext);
 		});
 	});
+
+	describe('getNextRunIndex', () => {
+		it('should return 0 as the default latest run index', () => {
+			const latestRunIndex = supplyDataContext.getNextRunIndex();
+			expect(latestRunIndex).toBe(0);
+		});
+
+		it('should return the length of the run execution data for the node', () => {
+			const runData = mock<IRunData>();
+			const runExecutionData = mock<IRunExecutionData>({
+				resultData: { runData: { [node.name]: [runData, runData] } },
+			});
+			const supplyDataContext = new SupplyDataContext(
+				workflow,
+				node,
+				additionalData,
+				mode,
+				runExecutionData,
+				runIndex,
+				connectionInputData,
+				inputData,
+				connectionType,
+				executeData,
+				[closeFn],
+				abortSignal,
+			);
+
+			const latestRunIndex = supplyDataContext.getNextRunIndex();
+
+			expect(latestRunIndex).toBe(2);
+		});
+	});
 });

packages/core/src/execution-engine/node-execution-context/supply-data-context.ts

@@ -167,16 +167,18 @@ export class SupplyDataContext extends BaseExecuteContext implements ISupplyData
 		return super.getInputItems(inputIndex, connectionType) ?? [];
 	}
 
+	getNextRunIndex(): number {
+		const nodeName = this.node.name;
+		return this.runExecutionData.resultData.runData[nodeName]?.length ?? 0;
+	}
+
 	/** @deprecated create a context object with inputData for every runIndex */
 	addInputData(
 		connectionType: AINodeConnectionType,
 		data: INodeExecutionData[][],
 	): { index: number } {
 		const nodeName = this.node.name;
-		let currentNodeRunIndex = 0;
-		if (this.runExecutionData.resultData.runData.hasOwnProperty(nodeName)) {
-			currentNodeRunIndex = this.runExecutionData.resultData.runData[nodeName].length;
-		}
+		const currentNodeRunIndex = this.getNextRunIndex();
 
 		this.addExecutionDataFunctions(
 			'input',

packages/core/src/execution-engine/node-execution-context/utils/__tests__/get-input-connection-data.test.ts

@@ -11,7 +11,9 @@ import type {
 	INodeType,
 	INodeTypes,
 	IExecuteFunctions,
+	IRunData,
 } from 'n8n-workflow';
+import type { ITaskData } from 'n8n-workflow';
 import { NodeConnectionTypes, NodeOperationError } from 'n8n-workflow';
 
 import { ExecuteContext } from '../../execute-context';
@@ -377,11 +379,19 @@ describe('makeHandleToolInvocation', () => {
 		execute,
 	});
 	const contextFactory = jest.fn();
+	const taskData = mock<ITaskData>();
+
+	let runExecutionData = mock<IRunExecutionData>({
+		resultData: {
+			runData: mock<IRunData>(),
+		},
+	});
 	const toolArgs = { key: 'value' };
 
 	beforeEach(() => {
 		jest.clearAllMocks();
 	});
+
 	it('should return stringified results when execution is successful', async () => {
 		const mockContext = mock<IExecuteFunctions>();
 		contextFactory.mockReturnValue(mockContext);
@@ -393,6 +403,7 @@ describe('makeHandleToolInvocation', () => {
 			contextFactory,
 			connectedNode,
 			connectedNodeType,
+			runExecutionData,
 		);
 		const result = await handleToolInvocation(toolArgs);
 
@@ -405,7 +416,6 @@ describe('makeHandleToolInvocation', () => {
 	it('should handle binary data and return a warning message', async () => {
 		const mockContext = mock<IExecuteFunctions>();
 		contextFactory.mockReturnValue(mockContext);
-
 		const mockResult = [[{ json: {}, binary: { file: 'data' } }]];
 		execute.mockResolvedValueOnce(mockResult);
 
@@ -413,6 +423,7 @@ describe('makeHandleToolInvocation', () => {
 			contextFactory,
 			connectedNode,
 			connectedNodeType,
+			runExecutionData,
 		);
 		const result = await handleToolInvocation(toolArgs);
 
@@ -439,7 +450,6 @@ describe('makeHandleToolInvocation', () => {
 			},
 		});
 		contextFactory.mockReturnValue(mockContext);
-
 		const mockResult = [[{ json: { a: 3 }, binary: { file: 'data' } }]];
 		execute.mockResolvedValueOnce(mockResult);
 
@@ -447,6 +457,7 @@ describe('makeHandleToolInvocation', () => {
 			contextFactory,
 			connectedNode,
 			connectedNodeType,
+			runExecutionData,
 		);
 		const result = await handleToolInvocation(toolArgs);
 
@@ -466,7 +477,6 @@ describe('makeHandleToolInvocation', () => {
 	it('should handle execution errors and return an error message', async () => {
 		const mockContext = mock<IExecuteFunctions>();
 		contextFactory.mockReturnValue(mockContext);
-
 		const error = new Error('Execution failed');
 		execute.mockRejectedValueOnce(error);
 
@@ -474,6 +484,7 @@ describe('makeHandleToolInvocation', () => {
 			contextFactory,
 			connectedNode,
 			connectedNodeType,
+			runExecutionData,
 		);
 		const result = await handleToolInvocation(toolArgs);
 
@@ -489,14 +500,42 @@ describe('makeHandleToolInvocation', () => {
 		const mockContext = mock<IExecuteFunctions>();
 		contextFactory.mockReturnValue(mockContext);
 
-		const handleToolInvocation = makeHandleToolInvocation(
+		let handleToolInvocation = makeHandleToolInvocation(
 			contextFactory,
 			connectedNode,
 			connectedNodeType,
+			runExecutionData,
 		);
+		await handleToolInvocation(toolArgs);
 
+		runExecutionData = mock<IRunExecutionData>({
+			resultData: {
+				runData: {
+					[connectedNode.name]: [taskData],
+				},
+			},
+		});
+		handleToolInvocation = makeHandleToolInvocation(
+			contextFactory,
+			connectedNode,
+			connectedNodeType,
+			runExecutionData,
+		);
 		await handleToolInvocation(toolArgs);
-		await handleToolInvocation(toolArgs);
+
+		runExecutionData = mock<IRunExecutionData>({
+			resultData: {
+				runData: {
+					[connectedNode.name]: [taskData, taskData],
+				},
+			},
+		});
+		handleToolInvocation = makeHandleToolInvocation(
+			contextFactory,
+			connectedNode,
+			connectedNodeType,
+			runExecutionData,
+		);
 		await handleToolInvocation(toolArgs);
 
 		expect(contextFactory).toHaveBeenCalledWith(0);

packages/core/src/execution-engine/node-execution-context/utils/get-input-connection-data.ts

@@ -28,19 +28,28 @@ import type { ExecuteContext, WebhookContext } from '../../node-execution-contex
 // eslint-disable-next-line import/no-cycle
 import { SupplyDataContext } from '../../node-execution-context/supply-data-context';
 
+function getNextRunIndex(runExecutionData: IRunExecutionData, nodeName: string) {
+	return runExecutionData.resultData.runData[nodeName]?.length ?? 0;
+}
+
 export function makeHandleToolInvocation(
 	contextFactory: (runIndex: number) => ISupplyDataFunctions,
 	node: INode,
 	nodeType: INodeType,
+	runExecutionData: IRunExecutionData,
 ) {
 	/**
 	 * This keeps track of how many times this specific AI tool node has been invoked.
 	 * It is incremented on every invocation of the tool to keep the output of each invocation separate from each other.
 	 */
-	let toolRunIndex = 0;
+	// We get the runIndex from the context to handle multiple executions
+	// of the same tool when the tool is used in a loop or in a parallel execution.
+	let runIndex = getNextRunIndex(runExecutionData, node.name);
+
 	return async (toolArgs: IDataObject) => {
-		const runIndex = toolRunIndex++;
-		const context = contextFactory(runIndex);
+		// Increment the runIndex for the next invocation
+		const localRunIndex = runIndex++;
+		const context = contextFactory(localRunIndex);
 		context.addInputData(NodeConnectionTypes.AiTool, [[{ json: toolArgs }]]);
 
 		try {
@@ -64,13 +73,13 @@ export function makeHandleToolInvocation(
 			}
 
 			// Add output data to the context
-			context.addOutputData(NodeConnectionTypes.AiTool, runIndex, [[{ json: { response } }]]);
+			context.addOutputData(NodeConnectionTypes.AiTool, localRunIndex, [[{ json: { response } }]]);
 
 			// Return the stringified results
 			return JSON.stringify(response);
 		} catch (error) {
 			const nodeError = new NodeOperationError(node, error as Error);
-			context.addOutputData(NodeConnectionTypes.AiTool, runIndex, nodeError);
+			context.addOutputData(NodeConnectionTypes.AiTool, localRunIndex, nodeError);
 			return 'Error during node execution: ' + (nodeError.description ?? nodeError.message);
 		}
 	};
@@ -153,6 +162,7 @@ export async function getInputConnectionData(
 						(i) => contextFactory(i, {}),
 						connectedNode,
 						connectedNodeType,
+						runExecutionData,
 					),
 				});
 				nodes.push(supplyData);

packages/workflow/src/Interfaces.ts

@@ -992,6 +992,7 @@ export type ISupplyDataFunctions = ExecuteFunctions.GetNodeParameterFn &
 		| 'sendMessageToUI'
 		| 'helpers'
 	> & {
+		getNextRunIndex(): number;
 		continueOnFail(): boolean;
 		evaluateExpression(expression: string, itemIndex: number): NodeParameterValueType;
 		getWorkflowDataProxy(itemIndex: number): IWorkflowDataProxyData;