fix(core): Make MCP executions asynchronous (#27762)

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

packages/cli/src/modules/mcp/__tests__/execute-workflow.tool.test.ts

@@ -7,7 +7,6 @@ import {
 	WEBHOOK_NODE_TYPE,
 	type INode,
 	type IWorkflowExecutionDataProcess,
-	UnexpectedError,
 } from 'n8n-workflow';
 import { v4 as uuid } from 'uuid';
 
@@ -15,7 +14,6 @@ import { createWorkflow } from './mock.utils';
 import { WorkflowAccessError } from '../mcp.errors';
 import { createExecuteWorkflowTool, executeWorkflow } from '../tools/execute-workflow.tool';
 
-import { ActiveExecutions } from '@/active-executions';
 import { McpService } from '@/modules/mcp/mcp.service';
 import { Telemetry } from '@/telemetry';
 import { WorkflowRunner } from '@/workflow-runner';
@@ -24,14 +22,12 @@ import { WorkflowFinderService } from '@/workflows/workflow-finder.service';
 describe('execute-workflow MCP tool', () => {
 	const user = Object.assign(new User(), { id: 'user-1' });
 	let workflowFinderService: WorkflowFinderService;
-	let activeExecutions: ActiveExecutions;
 	let workflowRunner: WorkflowRunner;
 	let telemetry: Telemetry;
 	let mcpService: McpService;
 
 	beforeEach(() => {
 		workflowFinderService = mockInstance(WorkflowFinderService);
-		activeExecutions = mockInstance(ActiveExecutions);
 		workflowRunner = mockInstance(WorkflowRunner);
 		telemetry = mockInstance(Telemetry, {
 			track: jest.fn(),
@@ -46,7 +42,6 @@ describe('execute-workflow MCP tool', () => {
 			const tool = createExecuteWorkflowTool(
 				user,
 				workflowFinderService,
-				activeExecutions,
 				workflowRunner,
 				telemetry,
 				mcpService,
@@ -56,7 +51,7 @@ describe('execute-workflow MCP tool', () => {
 			expect(tool.config).toBeDefined();
 			expect(typeof tool.config.description).toBe('string');
 			expect(tool.config.description).toBe(
-				'Execute a workflow by ID. Returns execution ID and status. To get the full execution results, use the get_execution tool with the returned execution ID. Before executing always ensure you know the input schema by first using the get_workflow_details tool and consulting workflow description',
+				'Execute a workflow by ID. Returns the execution ID immediately without waiting for completion. Before executing always ensure you know the input schema by first using the get_workflow_details tool and consulting workflow description',
 			);
 			expect(tool.config.inputSchema).toBeDefined();
 			expect(tool.config.outputSchema).toBeDefined();
@@ -73,7 +68,6 @@ describe('execute-workflow MCP tool', () => {
 					executeWorkflow(
 						user,
 						workflowFinderService,
-						activeExecutions,
 						workflowRunner,
 						mcpService,
 						'any-workflow',
@@ -93,7 +87,6 @@ describe('execute-workflow MCP tool', () => {
 					executeWorkflow(
 						user,
 						workflowFinderService,
-						activeExecutions,
 						workflowRunner,
 						mcpService,
 						'unpublished-workflow',
@@ -112,15 +105,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('execution-id');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: { runData: {} } },
-				});
 
 				const result = await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'unpublished-workflow',
@@ -128,7 +116,7 @@ describe('execute-workflow MCP tool', () => {
 					'manual',
 				);
 
-				expect(result.status).toBe('success');
+				expect(result.status).toBe('started');
 				expect(result.executionId).toBe('execution-id');
 			});
 
@@ -150,15 +138,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('execution-id');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: { runData: {} } },
-				});
 
 				const result = await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'manual-trigger-workflow',
@@ -166,7 +149,7 @@ describe('execute-workflow MCP tool', () => {
 					'manual',
 				);
 
-				expect(result.status).toBe('success');
+				expect(result.status).toBe('started');
 				expect(result.executionId).toBe('execution-id');
 				expect(workflowRunner.run).toHaveBeenCalledWith(
 					expect.objectContaining({
@@ -199,15 +182,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('execution-id');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: { runData: {} } },
-				});
 
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'manual-workflow-with-pindata',
@@ -247,15 +225,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('execution-id');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: { runData: {} } },
-				});
 
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'production-workflow-with-pindata',
@@ -293,7 +266,6 @@ describe('execute-workflow MCP tool', () => {
 					executeWorkflow(
 						user,
 						workflowFinderService,
-						activeExecutions,
 						workflowRunner,
 						mcpService,
 						'unsupported-trigger',
@@ -305,7 +277,6 @@ describe('execute-workflow MCP tool', () => {
 					executeWorkflow(
 						user,
 						workflowFinderService,
-						activeExecutions,
 						workflowRunner,
 						mcpService,
 						'unsupported-trigger',
@@ -335,7 +306,6 @@ describe('execute-workflow MCP tool', () => {
 					executeWorkflow(
 						user,
 						workflowFinderService,
-						activeExecutions,
 						workflowRunner,
 						mcpService,
 						'unsupported-trigger',
@@ -367,7 +337,6 @@ describe('execute-workflow MCP tool', () => {
 					executeWorkflow(
 						user,
 						workflowFinderService,
-						activeExecutions,
 						workflowRunner,
 						mcpService,
 						'disabled-trigger',
@@ -395,21 +364,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-123');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: {
-						resultData: {
-							runData: {
-								WebhookNode: [{ data: { main: [[{ json: { result: 'webhook success' } }]] } }],
-							},
-						},
-					},
-				});
 
 				const result = await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'webhook-workflow',
@@ -425,7 +383,7 @@ describe('execute-workflow MCP tool', () => {
 				);
 
 				expect(result).toMatchObject({
-					status: 'success',
+					status: 'started',
 					executionId: 'exec-123',
 				});
 
@@ -463,15 +421,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-456');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'webhook-workflow',
@@ -518,15 +471,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-789');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				const result = await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'chat-workflow',
@@ -537,7 +485,7 @@ describe('execute-workflow MCP tool', () => {
 				);
 
 				expect(result).toMatchObject({
-					status: 'success',
+					status: 'started',
 					executionId: 'exec-789',
 				});
 
@@ -576,15 +524,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-101');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				const result = await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'form-workflow',
@@ -599,7 +542,7 @@ describe('execute-workflow MCP tool', () => {
 				);
 
 				expect(result).toMatchObject({
-					status: 'success',
+					status: 'started',
 					executionId: 'exec-101',
 				});
 
@@ -622,8 +565,8 @@ describe('execute-workflow MCP tool', () => {
 			});
 		});
 
-		describe('execution results handling', () => {
-			test('handles successful execution', async () => {
+		describe('execution start', () => {
+			test('returns started status with execution ID', async () => {
 				const workflow = createWorkflow({
 					activeVersionId: uuid(),
 					nodes: [
@@ -640,21 +583,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-success');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: {
-						resultData: {
-							runData: {
-								WebhookNode: [{ data: { main: [[{ json: { output: 'success' } }]] } }],
-							},
-						},
-					},
-				});
 
 				const result = await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'success-workflow',
@@ -662,145 +594,10 @@ describe('execute-workflow MCP tool', () => {
 				);
 
 				expect(result).toMatchObject({
-					status: 'success',
+					status: 'started',
 					executionId: 'exec-success',
 				});
-			});
-
-			test('handles execution with error status', async () => {
-				const workflow = createWorkflow({
-					activeVersionId: uuid(),
-					nodes: [
-						{
-							id: 'node-1',
-							name: 'WebhookNode',
-							type: WEBHOOK_NODE_TYPE,
-							typeVersion: 1,
-							position: [0, 0],
-							disabled: false,
-							parameters: {},
-						} as INode,
-					],
-				});
-				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
-				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-error');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'error',
-					data: {
-						resultData: {
-							error: {
-								message: 'Workflow execution failed',
-								name: 'ExecutionError',
-							},
-						},
-					},
-				});
-
-				const result = await executeWorkflow(
-					user,
-					workflowFinderService,
-					activeExecutions,
-					workflowRunner,
-					mcpService,
-					'error-workflow',
-					undefined,
-				);
-
-				expect(result).toMatchObject({
-					status: 'error',
-					executionId: 'exec-error',
-					error: 'Workflow execution failed',
-				});
-			});
-
-			test('handles execution with result data error', async () => {
-				const workflow = createWorkflow({
-					activeVersionId: uuid(),
-					nodes: [
-						{
-							id: 'node-1',
-							name: 'WebhookNode',
-							type: WEBHOOK_NODE_TYPE,
-							typeVersion: 1,
-							position: [0, 0],
-							disabled: false,
-							parameters: {},
-						} as INode,
-					],
-				});
-				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
-				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-data-error');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: {
-						resultData: {
-							error: {
-								message: 'Node execution failed',
-								name: 'NodeExecutionError',
-							},
-						},
-					},
-				});
-
-				const result = await executeWorkflow(
-					user,
-					workflowFinderService,
-					activeExecutions,
-					workflowRunner,
-					mcpService,
-					'data-error-workflow',
-					undefined,
-				);
-
-				expect(result).toMatchObject({
-					status: 'error',
-					executionId: 'exec-data-error',
-					error: 'Node execution failed',
-				});
-			});
-
-			test('handles workflow returning undefined data', async () => {
-				const workflow = createWorkflow({
-					activeVersionId: uuid(),
-					nodes: [
-						{
-							id: 'node-1',
-							name: 'WebhookNode',
-							type: WEBHOOK_NODE_TYPE,
-							typeVersion: 1,
-							position: [0, 0],
-							disabled: false,
-							parameters: {},
-						} as INode,
-					],
-				});
-				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
-				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-no-data');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue(undefined);
-
-				await expect(
-					executeWorkflow(
-						user,
-						workflowFinderService,
-						activeExecutions,
-						workflowRunner,
-						mcpService,
-						'no-data-workflow',
-						undefined,
-					),
-				).rejects.toThrow(UnexpectedError);
-
-				await expect(
-					executeWorkflow(
-						user,
-						workflowFinderService,
-						activeExecutions,
-						workflowRunner,
-						mcpService,
-						'no-data-workflow',
-						undefined,
-					),
-				).rejects.toThrow('Workflow did not return any data');
+				expect(result.error).toBeUndefined();
 			});
 		});
 
@@ -822,15 +619,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-no-inputs');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'no-inputs-workflow',
@@ -871,15 +663,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-telemetry');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				const tool = createExecuteWorkflowTool(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					telemetry,
 					mcpService,
@@ -909,7 +696,7 @@ describe('execute-workflow MCP tool', () => {
 							success: true,
 							data: {
 								executionId: 'exec-telemetry',
-								status: 'success',
+								status: 'started',
 							},
 						},
 					}),
@@ -922,7 +709,6 @@ describe('execute-workflow MCP tool', () => {
 				const tool = createExecuteWorkflowTool(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					telemetry,
 					mcpService,
@@ -960,7 +746,6 @@ describe('execute-workflow MCP tool', () => {
 				const tool = createExecuteWorkflowTool(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					telemetry,
 					mcpService,
@@ -1029,15 +814,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-multi');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'multi-trigger-workflow',
@@ -1059,50 +839,6 @@ describe('execute-workflow MCP tool', () => {
 			beforeEach(() => {
 				queueModeMcpService = mockInstance(McpService, {
 					isQueueMode: true,
-					createPendingResponse: jest.fn().mockReturnValue({
-						promise: Promise.resolve({
-							status: 'success',
-							data: { resultData: { runData: {} } },
-						}),
-						resolve: jest.fn(),
-						reject: jest.fn(),
-					}),
-				});
-			});
-
-			test('uses pending response promise in queue mode', async () => {
-				const workflow = createWorkflow({
-					activeVersionId: uuid(),
-					nodes: [
-						{
-							id: 'node-1',
-							name: 'WebhookNode',
-							type: WEBHOOK_NODE_TYPE,
-							typeVersion: 1,
-							position: [0, 0],
-							disabled: false,
-							parameters: {},
-						} as INode,
-					],
-				});
-				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
-				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-queue');
-
-				const result = await executeWorkflow(
-					user,
-					workflowFinderService,
-					activeExecutions,
-					workflowRunner,
-					queueModeMcpService,
-					'queue-workflow',
-					undefined,
-				);
-
-				expect(queueModeMcpService.createPendingResponse).toHaveBeenCalledWith('exec-queue');
-				expect(activeExecutions.getPostExecutePromise).not.toHaveBeenCalled();
-				expect(result).toMatchObject({
-					status: 'success',
-					executionId: 'exec-queue',
 				});
 			});
 
@@ -1127,7 +863,6 @@ describe('execute-workflow MCP tool', () => {
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					queueModeMcpService,
 					'mcp-meta-workflow',
@@ -1159,15 +894,10 @@ describe('execute-workflow MCP tool', () => {
 				});
 				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
 				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-regular');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
 
 				await executeWorkflow(
 					user,
 					workflowFinderService,
-					activeExecutions,
 					workflowRunner,
 					mcpService,
 					'regular-workflow',
@@ -1180,41 +910,6 @@ describe('execute-workflow MCP tool', () => {
 				// determines whether queue mode MCP handling is applied
 				expect(runCall.isMcpExecution).toBe(false);
 			});
-
-			test('uses activeExecutions.getPostExecutePromise in regular mode', async () => {
-				const workflow = createWorkflow({
-					activeVersionId: uuid(),
-					nodes: [
-						{
-							id: 'node-1',
-							name: 'WebhookNode',
-							type: WEBHOOK_NODE_TYPE,
-							typeVersion: 1,
-							position: [0, 0],
-							disabled: false,
-							parameters: {},
-						} as INode,
-					],
-				});
-				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(workflow);
-				(workflowRunner.run as jest.Mock).mockResolvedValue('exec-regular-2');
-				(activeExecutions.getPostExecutePromise as jest.Mock).mockResolvedValue({
-					status: 'success',
-					data: { resultData: {} },
-				});
-
-				await executeWorkflow(
-					user,
-					workflowFinderService,
-					activeExecutions,
-					workflowRunner,
-					mcpService,
-					'regular-workflow-2',
-					undefined,
-				);
-
-				expect(activeExecutions.getPostExecutePromise).toHaveBeenCalledWith('exec-regular-2');
-			});
 		});
 	});
 });

packages/cli/src/modules/mcp/__tests__/get-execution.tool.test.ts

@@ -696,6 +696,68 @@ describe('get-execution MCP tool', () => {
 				});
 			});
 
+			test('handles execution data with circular references', async () => {
+				const tool = createGetExecutionTool(
+					user,
+					executionRepository,
+					workflowFinderService,
+					telemetry,
+				);
+
+				const mockExecutionData = createEmptyRunExecutionData();
+				// Create circular reference in node output data
+				const circularObj: Record<string, string | Record<string, unknown>> = { value: 'test' };
+				circularObj.self = circularObj;
+
+				mockExecutionData.resultData.runData = {
+					Node1: [
+						{
+							executionIndex: 0,
+							startTime: 0,
+							executionTime: 100,
+							source: [],
+							data: { main: [[{ json: circularObj }]] },
+						},
+					],
+				};
+
+				const mockExecution = {
+					id: 'execution-1',
+					workflowId: 'workflow-1',
+					mode: 'manual',
+					status: 'success',
+					startedAt: new Date('2025-01-01T00:00:00.000Z'),
+					stoppedAt: new Date('2025-01-01T00:01:00.000Z'),
+					retryOf: null,
+					retrySuccessId: null,
+					waitTill: null,
+					data: mockExecutionData,
+				};
+
+				(workflowFinderService.findWorkflowForUser as jest.Mock).mockResolvedValue(mockWorkflow);
+				(executionRepository.findWithUnflattenedData as jest.Mock).mockResolvedValue(mockExecution);
+
+				const result = await tool.handler(
+					{
+						workflowId: 'workflow-1',
+						executionId: 'execution-1',
+						includeData: true,
+						nodeNames: undefined,
+						truncateData: undefined,
+					},
+					{} as never,
+				);
+
+				expect(result.structuredContent).toMatchObject({
+					execution: {
+						id: 'execution-1',
+						status: 'success',
+					},
+				});
+				// Should not return an error — circular refs must be handled gracefully
+				expect(result.structuredContent).not.toHaveProperty('error');
+			});
+
 			test('handles execution with waitTill', async () => {
 				const tool = createGetExecutionTool(
 					user,

packages/cli/src/modules/mcp/mcp.service.ts

@@ -121,7 +121,6 @@ export class McpService {
 		const executeWorkflowTool = createExecuteWorkflowTool(
 			user,
 			this.workflowFinderService,
-			this.activeExecutions,
 			this.workflowRunner,
 			this.telemetry,
 			this,

packages/cli/src/modules/mcp/tools/execute-workflow.tool.ts

@@ -1,4 +1,3 @@
-import { Time } from '@n8n/constants';
 import type { User } from '@n8n/db';
 import {
 	CHAT_TRIGGER_NODE_TYPE,
@@ -21,17 +20,15 @@ import {
 	SUPPORTED_PRODUCTION_MCP_TRIGGERS,
 	USER_CALLED_MCP_TOOL_EVENT,
 } from '../mcp.constants';
-import { McpExecutionTimeoutError, WorkflowAccessError } from '../mcp.errors';
+import { WorkflowAccessError } from '../mcp.errors';
 import type {
 	ExecuteWorkflowsInputMeta,
 	ToolDefinition,
 	UserCalledMCPToolEventPayload,
 } from '../mcp.types';
 import { findMcpSupportedTrigger } from '../mcp.utils';
-import { waitForExecutionResult, WORKFLOW_EXECUTION_TIMEOUT_MS } from './execution-utils';
 import { getMcpWorkflow, type FoundWorkflow } from './workflow-validation.utils';
 
-import type { ActiveExecutions } from '@/active-executions';
 import type { McpService } from '@/modules/mcp/mcp.service';
 import type { Telemetry } from '@/telemetry';
 import type { WorkflowRunner } from '@/workflow-runner';
@@ -86,22 +83,19 @@ const inputSchema = z.object({
 
 type ExecuteWorkflowOutput = {
 	executionId: string | null;
-	status: 'success' | 'error' | 'running' | 'waiting' | 'canceled' | 'crashed' | 'new' | 'unknown';
+	status: 'started' | 'error';
 	error?: string;
 };
 
 const outputSchema = {
 	executionId: z.string().nullable(),
-	status: z
-		.enum(['success', 'error', 'running', 'waiting', 'canceled', 'crashed', 'new', 'unknown'])
-		.describe('The status of the execution'),
+	status: z.enum(['started', 'error']).describe('The status of the execution'),
 	error: z.string().optional().describe('Error message if the execution failed'),
 } satisfies z.ZodRawShape;
 
 export const createExecuteWorkflowTool = (
 	user: User,
 	workflowFinderService: WorkflowFinderService,
-	activeExecutions: ActiveExecutions,
 	workflowRunner: WorkflowRunner,
 	telemetry: Telemetry,
 	mcpService: McpService,
@@ -109,7 +103,7 @@ export const createExecuteWorkflowTool = (
 	name: 'execute_workflow',
 	config: {
 		description:
-			'Execute a workflow by ID. Returns execution ID and status. To get the full execution results, use the get_execution tool with the returned execution ID. Before executing always ensure you know the input schema by first using the get_workflow_details tool and consulting workflow description',
+			'Execute a workflow by ID. Returns the execution ID immediately without waiting for completion. Before executing always ensure you know the input schema by first using the get_workflow_details tool and consulting workflow description',
 		inputSchema: inputSchema.shape,
 		outputSchema,
 		annotations: {
@@ -130,7 +124,6 @@ export const createExecuteWorkflowTool = (
 			const output = await executeWorkflow(
 				user,
 				workflowFinderService,
-				activeExecutions,
 				workflowRunner,
 				mcpService,
 				workflowId,
@@ -139,15 +132,12 @@ export const createExecuteWorkflowTool = (
 			);
 
 			telemetryPayload.results = {
-				success: output.status === 'success',
+				success: true,
 				data: {
 					executionId: output.executionId,
 					status: output.status,
 				},
 			};
-			if (output.status === 'error' && output.error) {
-				telemetryPayload.results.error = output.error;
-			}
 			telemetry.track(USER_CALLED_MCP_TOOL_EVENT, telemetryPayload);
 
 			return {
@@ -156,7 +146,6 @@ export const createExecuteWorkflowTool = (
 			};
 		} catch (er) {
 			const error = ensureError(er);
-			const isTimeout = error instanceof McpExecutionTimeoutError;
 			const isAccessError = error instanceof WorkflowAccessError;
 
 			const errorInfo: Record<string, unknown> = {
@@ -173,16 +162,14 @@ export const createExecuteWorkflowTool = (
 			}
 
 			const output: ExecuteWorkflowOutput = {
-				executionId: isTimeout ? error.executionId : null,
+				executionId: null,
 				status: 'error',
-				error: isTimeout
-					? `Workflow execution timed out after ${WORKFLOW_EXECUTION_TIMEOUT_MS * Time.milliseconds.toSeconds} seconds (Enforced MCP timeout)`
-					: (error.message ?? `${error.constructor.name}: (no message)`),
+				error: error.message ?? `${error.constructor.name}: (no message)`,
 			};
 
 			telemetryPayload.results = {
 				success: false,
-				error: isTimeout ? 'Workflow execution timed out' : errorInfo,
+				error: errorInfo,
 				error_reason: isAccessError ? error.reason : undefined,
 			};
 			telemetry.track(USER_CALLED_MCP_TOOL_EVENT, telemetryPayload);
@@ -204,7 +191,6 @@ export const createExecuteWorkflowTool = (
 export const executeWorkflow = async (
 	user: User,
 	workflowFinderService: WorkflowFinderService,
-	activeExecutions: ActiveExecutions,
 	workflowRunner: WorkflowRunner,
 	mcpService: McpService,
 	workflowId: string,
@@ -228,15 +214,10 @@ export const executeWorkflow = async (
 	);
 
 	const executionId = await workflowRunner.run(runData);
-	const data = await waitForExecutionResult(executionId, activeExecutions, mcpService);
-	const hasError = data.status === 'error' || data.data.resultData?.error;
 
 	return {
 		executionId,
-		status: hasError ? 'error' : data.status,
-		error: hasError
-			? (data.data.resultData?.error?.message ?? 'Execution completed with errors')
-			: undefined,
+		status: 'started',
 	};
 };
 

packages/cli/src/modules/mcp/tools/get-execution.tool.ts

@@ -18,7 +18,7 @@ const inputSchema = z.object({
 		.boolean()
 		.optional()
 		.describe(
-			'Whether to include the full execution result data. Defaults to false (metadata only). Set to true to include node inputs/outputs.',
+			'Whether to include the full execution result data. Defaults to false (metadata only). Set to true to include node inputs/outputs. Use `false` to quickly check execution status',
 		),
 	nodeNames: z
 		.array(z.string())
@@ -153,7 +153,7 @@ export const createGetExecutionTool = (
 			telemetry.track(USER_CALLED_MCP_TOOL_EVENT, telemetryPayload);
 
 			return {
-				content: [{ type: 'text', text: jsonStringify(output) }],
+				content: [{ type: 'text', text: jsonStringify(output, { replaceCircularRefs: true }) }],
 				structuredContent: output,
 			};
 		} catch (er) {
@@ -186,7 +186,7 @@ export const createGetExecutionTool = (
 			telemetry.track(USER_CALLED_MCP_TOOL_EVENT, telemetryPayload);
 
 			return {
-				content: [{ type: 'text', text: jsonStringify(output) }],
+				content: [{ type: 'text', text: jsonStringify(output, { replaceCircularRefs: true }) }],
 				structuredContent: output,
 			};
 		}

packages/testing/playwright/services/mcp-api-helper.ts

@@ -119,7 +119,7 @@ export interface WorkflowDetailsResult {
 /** Response from execute_workflow tool */
 export interface ExecuteWorkflowResult {
 	executionId: string | null;
-	status: 'success' | 'error' | 'running' | 'waiting' | 'canceled' | 'crashed' | 'new' | 'unknown';
+	status: 'started' | 'error';
 	error?: string;
 }
 

packages/testing/playwright/tests/e2e/mcp/mcp-service.spec.ts

@@ -301,7 +301,7 @@ test.describe(
 				const { apiKey } = await api.rotateMcpApiKey();
 				const result = await api.mcp.internalMcpExecuteWorkflow(apiKey, workflowId);
 
-				expect(result.status).toBe('success');
+				expect(result.status).toBe('started');
 				expect(result.executionId).toBeTruthy();
 			});
 
@@ -343,7 +343,7 @@ test.describe(
 					},
 				});
 
-				expect(result.status).toBe('success');
+				expect(result.status).toBe('started');
 				expect(result.executionId).toBeTruthy();
 			});
 		});
@@ -358,9 +358,24 @@ test.describe(
 				const { apiKey } = await api.rotateMcpApiKey();
 
 				const execResult = await api.mcp.internalMcpExecuteWorkflow(apiKey, workflowId);
-				expect(execResult.status).toBe('success');
+				expect(execResult.status).toBe('started');
 				expect(execResult.executionId).toBeTruthy();
 
+				// Poll for execution completion since executions are asynchronous
+				await expect
+					.poll(
+						async () => {
+							const r = await api.mcp.internalMcpGetExecution(
+								apiKey,
+								workflowId,
+								execResult.executionId!,
+							);
+							return r.execution?.status;
+						},
+						{ timeout: 30_000, intervals: [1_000] },
+					)
+					.toBe('success');
+
 				const result = await api.mcp.internalMcpGetExecution(
 					apiKey,
 					workflowId,
@@ -371,7 +386,6 @@ test.describe(
 				expect(result.execution).toBeDefined();
 				expect(result.execution!.id).toBe(execResult.executionId);
 				expect(result.execution!.workflowId).toBe(workflowId);
-				expect(result.execution!.status).toBe('success');
 				expect(result.data).toBeDefined();
 			});
 		});