feat(LmChatAnthropic Node): Add streaming option (#30991)

Co-authored-by: oleg <me@olegivaniv.com>

packages/@n8n/nodes-langchain/nodes/llms/LMChatAnthropic/LmChatAnthropic.node.ts

@@ -434,6 +434,14 @@ export class LmChatAnthropic implements INodeType {
 							},
 						},
 					},
+					{
+						displayName: 'Stream Responses',
+						name: 'streaming',
+						type: 'boolean',
+						default: false,
+						description:
+							'Whether the model should stream its response over Server-Sent Events instead of returning a single non-streamed payload. Final output shape is unchanged.',
+					},
 				],
 			},
 		],
@@ -469,6 +477,7 @@ export class LmChatAnthropic implements INodeType {
 			thinkingBudget?: number;
 			thinkingMode?: 'disabled' | 'adaptive' | 'manual';
 			effort?: 'low' | 'medium' | 'high' | 'xhigh' | 'max';
+			streaming?: boolean;
 		};
 
 		const isOpus47Model = modelName.startsWith('claude-opus-4-7');
@@ -577,6 +586,7 @@ export class LmChatAnthropic implements INodeType {
 			onFailedAttempt: makeN8nLlmFailedAttemptHandler(this, gatewayErrorHandler),
 			invocationKwargs,
 			clientOptions,
+			streaming: options.streaming ?? false,
 		};
 
 		// Opus 4.7 rejects temperature/topK/topP at the SDK layer regardless of thinking mode

packages/@n8n/nodes-langchain/nodes/llms/LMChatAnthropic/test/LmChatAnthropic.test.ts

@@ -225,6 +225,42 @@ describe('LmChatAnthropic', () => {
 			);
 		});
 
+		it('should default streaming to false when option is omitted', async () => {
+			const mockContext = setupMockContext();
+
+			mockContext.getNodeParameter = vi.fn().mockImplementation((paramName: string) => {
+				if (paramName === 'model.value') return 'claude-sonnet-4-20250514';
+				if (paramName === 'options') return {};
+				return undefined;
+			});
+
+			await lmChatAnthropic.supplyData.call(mockContext, 0);
+
+			expect(MockedChatAnthropic).toHaveBeenCalledWith(
+				expect.objectContaining({
+					streaming: false,
+				}),
+			);
+		});
+
+		it('should pass streaming=true to ChatAnthropic when option is set', async () => {
+			const mockContext = setupMockContext();
+
+			mockContext.getNodeParameter = vi.fn().mockImplementation((paramName: string) => {
+				if (paramName === 'model.value') return 'claude-sonnet-4-20250514';
+				if (paramName === 'options') return { streaming: true };
+				return undefined;
+			});
+
+			await lmChatAnthropic.supplyData.call(mockContext, 0);
+
+			expect(MockedChatAnthropic).toHaveBeenCalledWith(
+				expect.objectContaining({
+					streaming: true,
+				}),
+			);
+		});
+
 		it('should remove topP from model when not explicitly set', async () => {
 			const mockContext = setupMockContext();