fix(core): Preserve code-builder thread suffix when parsing session (#30829)

Co-authored-by: n8n-cat-bot[bot] <n8n-cat-bot[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
Co-authored-by: Declan Carroll <declan@n8n.io>

packages/@n8n/ai-workflow-builder.ee/src/ai-workflow-builder-agent.service.ts

@@ -417,9 +417,10 @@ export class AiWorkflowBuilderService {
 		this.onTelemetryEvent('Builder replied to user message', properties);
 	}
 
-	async getSessions(workflowId: string | undefined, user?: IUser) {
+	async getSessions(workflowId: string | undefined, user?: IUser, isCodeBuilder?: boolean) {
 		const userId = user?.id?.toString();
-		return await this.sessionManager.getSessions(workflowId, userId, 'code-builder');
+		const agentType = isCodeBuilder ? 'code-builder' : undefined;
+		return await this.sessionManager.getSessions(workflowId, userId, agentType);
 	}
 
 	async getBuilderInstanceCredits(

packages/@n8n/ai-workflow-builder.ee/src/test/ai-workflow-builder-agent.service.test.ts

@@ -550,7 +550,7 @@ describe('AiWorkflowBuilderService', () => {
 			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
 				undefined,
 				'test-user-id',
-				'code-builder',
+				undefined,
 			);
 		});
 
@@ -578,6 +578,19 @@ describe('AiWorkflowBuilderService', () => {
 				lastUpdated: '2023-12-01T12:00:00Z',
 			});
 			expect(result.sessions[0].messages).toHaveLength(2);
+			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
+				workflowId,
+				'test-user-id',
+				undefined,
+			);
+		});
+
+		it('should request code-builder threads when isCodeBuilder is true', async () => {
+			const workflowId = 'test-workflow';
+			(mockSessionManager.getSessions as jest.Mock).mockResolvedValue({ sessions: [] });
+
+			await service.getSessions(workflowId, mockUser, true);
+
 			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
 				workflowId,
 				'test-user-id',
@@ -597,7 +610,7 @@ describe('AiWorkflowBuilderService', () => {
 			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
 				workflowId,
 				'test-user-id',
-				'code-builder',
+				undefined,
 			);
 		});
 
@@ -621,7 +634,7 @@ describe('AiWorkflowBuilderService', () => {
 			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
 				workflowId,
 				'test-user-id',
-				'code-builder',
+				undefined,
 			);
 		});
 
@@ -645,7 +658,7 @@ describe('AiWorkflowBuilderService', () => {
 			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
 				workflowId,
 				'test-user-id',
-				'code-builder',
+				undefined,
 			);
 		});
 
@@ -658,11 +671,7 @@ describe('AiWorkflowBuilderService', () => {
 			const result = await service.getSessions(workflowId);
 
 			expect(result.sessions).toEqual([]);
-			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
-				workflowId,
-				undefined,
-				'code-builder',
-			);
+			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(workflowId, undefined, undefined);
 		});
 	});
 
@@ -709,7 +718,7 @@ describe('AiWorkflowBuilderService', () => {
 			expect(mockSessionManager.getSessions).toHaveBeenCalledWith(
 				workflowId,
 				'test-user-id',
-				'code-builder',
+				undefined,
 			);
 		});
 	});

packages/@n8n/api-types/src/dto/ai/ai-session-retrieval-request.dto.ts

@@ -4,4 +4,5 @@ import { Z } from '../../zod-class';
 
 export class AiSessionRetrievalRequestDto extends Z.class({
 	workflowId: z.string().optional(),
+	codeBuilder: z.boolean().optional(),
 }) {}

packages/cli/src/controllers/__tests__/ai.controller.test.ts

@@ -530,6 +530,51 @@ describe('AiController', () => {
 		});
 	});
 
+	describe('getSessions', () => {
+		it('should call workflowBuilderService.getSessions with correct parameters', async () => {
+			const mockSessions = { sessions: [] };
+			const payload = { workflowId: 'workflow123' };
+
+			workflowBuilderService.getSessions.mockResolvedValue(mockSessions);
+
+			const result = await controller.getSessions(request, response, payload);
+
+			expect(workflowBuilderService.getSessions).toHaveBeenCalledWith(
+				payload.workflowId,
+				request.user,
+				undefined,
+			);
+			expect(result).toEqual(mockSessions);
+		});
+
+		it('should forward the codeBuilder flag to the service', async () => {
+			const mockSessions = { sessions: [] };
+			const payload = { workflowId: 'workflow123', codeBuilder: true as const };
+
+			workflowBuilderService.getSessions.mockResolvedValue(mockSessions);
+
+			const result = await controller.getSessions(request, response, payload);
+
+			expect(workflowBuilderService.getSessions).toHaveBeenCalledWith(
+				payload.workflowId,
+				request.user,
+				true,
+			);
+			expect(result).toEqual(mockSessions);
+		});
+
+		it('should throw InternalServerError when service throws an error', async () => {
+			const payload = { workflowId: 'workflow123' };
+			const mockError = new Error('Database error');
+
+			workflowBuilderService.getSessions.mockRejectedValue(mockError);
+
+			await expect(controller.getSessions(request, response, payload)).rejects.toThrow(
+				InternalServerError,
+			);
+		});
+	});
+
 	describe('truncateMessages', () => {
 		it('should call workflowBuilderService.truncateMessagesAfter with correct parameters', async () => {
 			const payload = {

packages/cli/src/controllers/ai.controller.ts

@@ -251,7 +251,11 @@ export class AiController {
 		@Body payload: AiSessionRetrievalRequestDto,
 	) {
 		try {
-			const sessions = await this.workflowBuilderService.getSessions(payload.workflowId, req.user);
+			const sessions = await this.workflowBuilderService.getSessions(
+				payload.workflowId,
+				req.user,
+				payload.codeBuilder,
+			);
 			return sessions;
 		} catch (e) {
 			assert(e instanceof Error);

packages/cli/src/modules/workflow-builder/__tests__/workflow-builder-session.repository.test.ts

@@ -69,6 +69,27 @@ describe('WorkflowBuilderSessionRepository', () => {
 		it('should throw error for empty thread ID', async () => {
 			await expect(repository.getSession('')).rejects.toThrow('Invalid thread ID format: ');
 		});
+
+		it('should strip the code-builder "-code" suffix from the userId', async () => {
+			entityManager.findOne.mockResolvedValueOnce(null);
+
+			const userUuid = 'af6cc09d-e809-41c6-9e92-ca26dfd11487';
+			await repository.getSession(`workflow-wf123-user-${userUuid}-code`);
+
+			expect(entityManager.findOne).toHaveBeenCalledWith(WorkflowBuilderSession, {
+				where: { workflowId: 'wf123', userId: userUuid },
+			});
+		});
+
+		it('should not strip "-code" from a non-suffixed userId', async () => {
+			entityManager.findOne.mockResolvedValueOnce(null);
+
+			await repository.getSession('workflow-wf123-user-user456');
+
+			expect(entityManager.findOne).toHaveBeenCalledWith(WorkflowBuilderSession, {
+				where: { workflowId: 'wf123', userId: 'user456' },
+			});
+		});
 	});
 
 	describe('getSession', () => {

packages/cli/src/modules/workflow-builder/workflow-builder-session.repository.ts

@@ -76,8 +76,11 @@ export class WorkflowBuilderSessionRepository
 	}
 
 	private parseThreadId(threadId: string): { workflowId: string; userId: string } {
-		// Format: "workflow-{workflowId}-user-{userId}"
-		const match = threadId.match(/^workflow-(.+)-user-(.+)$/);
+		// Format: "workflow-{workflowId}-user-{userId}" with an optional "-code" suffix
+		// for the code-builder agent thread variant. Strip the suffix before parsing so
+		// the greedy userId capture doesn't swallow it (userId is a uuid column in PG).
+		const normalized = threadId.endsWith('-code') ? threadId.slice(0, -'-code'.length) : threadId;
+		const match = normalized.match(/^workflow-(.+)-user-(.+)$/);
 		if (!match) {
 			throw new Error(`Invalid thread ID format: ${threadId}`);
 		}

packages/cli/src/services/__tests__/ai-workflow-builder.service.test.ts

@@ -273,7 +273,7 @@ describe('WorkflowBuilderService', () => {
 			const result = await service.getSessions('workflow-123', mockUser);
 
 			expect(MockedAiWorkflowBuilderService).toHaveBeenCalledTimes(1);
-			expect(mockAiService.getSessions).toHaveBeenCalledWith('workflow-123', mockUser);
+			expect(mockAiService.getSessions).toHaveBeenCalledWith('workflow-123', mockUser, undefined);
 			expect(result).toEqual(mockSessions);
 		});
 
@@ -286,9 +286,21 @@ describe('WorkflowBuilderService', () => {
 
 			const result = await service.getSessions(undefined, mockUser);
 
-			expect(mockAiService.getSessions).toHaveBeenCalledWith(undefined, mockUser);
+			expect(mockAiService.getSessions).toHaveBeenCalledWith(undefined, mockUser, undefined);
 			expect(result).toEqual(mockSessions);
 		});
+
+		it('should forward the isCodeBuilder flag to the inner service', async () => {
+			const mockSessions = { sessions: [] };
+
+			const mockAiService = mock<AiWorkflowBuilderService>();
+			(mockAiService.getSessions as jest.Mock).mockResolvedValue(mockSessions);
+			MockedAiWorkflowBuilderService.mockImplementation(() => mockAiService);
+
+			await service.getSessions('workflow-123', mockUser, true);
+
+			expect(mockAiService.getSessions).toHaveBeenCalledWith('workflow-123', mockUser, true);
+		});
 	});
 
 	describe('onCreditsUpdated callback', () => {

packages/cli/src/services/ai-workflow-builder.service.ts

@@ -187,9 +187,9 @@ export class WorkflowBuilderService {
 		yield* service.chat(payload, user, abortSignal);
 	}
 
-	async getSessions(workflowId: string | undefined, user: IUser) {
+	async getSessions(workflowId: string | undefined, user: IUser, isCodeBuilder?: boolean) {
 		const service = await this.getService();
-		const sessions = await service.getSessions(workflowId, user);
+		const sessions = await service.getSessions(workflowId, user, isCodeBuilder);
 		return sessions;
 	}