From 4467ebecea23837160e82d46de7da534ab96a246 Mon Sep 17 00:00:00 2001
From: Benjamin Schroth <benjamin@n8n.io>
Date: Tue, 24 Mar 2026 17:45:41 +0100
Subject: [PATCH] fix(ChainLLM Node): Fix abort signal handling

---
 .../chains/ChainLLM/methods/chainExecutor.ts  |  5 +----
 .../ChainLLM/test/chainExecutor.test.ts       | 22 +++++++++++++++----
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/methods/chainExecutor.ts b/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/methods/chainExecutor.ts
index 13143a735303..5502c2ad7a61 100644
--- a/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/methods/chainExecutor.ts
+++ b/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/methods/chainExecutor.ts
@@ -108,10 +108,7 @@ async function executeSimpleChain({
 	const chain = prompt.pipe(llm).pipe(outputParser).withConfig(getTracingConfig(context));
 
 	// Execute the chain
-	const response = await chain.invoke({
-		query,
-		signal: context.getExecutionCancelSignal(),
-	});
+	const response = await chain.invoke({ query }, { signal: context.getExecutionCancelSignal() });
 
 	// Ensure response is always returned as an array
 	return [response];
diff --git a/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/test/chainExecutor.test.ts b/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/test/chainExecutor.test.ts
index 7e176f623a12..99b957798326 100644
--- a/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/test/chainExecutor.test.ts
+++ b/packages/@n8n/nodes-langchain/nodes/chains/ChainLLM/test/chainExecutor.test.ts
@@ -265,7 +265,10 @@ describe('chainExecutor', () => {
 			expect(tracing.getTracingConfig).toHaveBeenCalledWith(mockContext);
 		});
 
-		it('should execute a chain with a single output parser', async () => {
+		it('should execute a chain with a single output parser and pass signal as config', async () => {
+			const abortController = new AbortController();
+			mockContext.getExecutionCancelSignal.mockReturnValue(abortController.signal);
+
 			const fakeLLM = new FakeLLM({ response: 'Test response' });
 			const mockPromptTemplate = new PromptTemplate({
 				template: '{query}\n{formatInstructions}',
@@ -306,6 +309,11 @@ describe('chainExecutor', () => {
 			});
 
 			expect(result).toEqual([{ result: 'Test response' }]);
+			// Signal must be in the config (2nd arg), NOT bundled in the input (1st arg)
+			expect(mockChain.invoke).toHaveBeenCalledWith(
+				{ query: 'Hello' },
+				{ signal: abortController.signal },
+			);
 		});
 
 		it('should wrap non-array responses in an array', async () => {
@@ -345,8 +353,10 @@ describe('chainExecutor', () => {
 			expect(result).toEqual([{ result: 'Test response' }]);
 		});
 
-		it('should pass the execution cancel signal to the chain', async () => {
-			// For this test, we'll just verify that getExecutionCancelSignal is called
+		it('should pass the execution cancel signal as config, not as input', async () => {
+			const abortController = new AbortController();
+			mockContext.getExecutionCancelSignal.mockReturnValue(abortController.signal);
+
 			const fakeLLM = new FakeLLM({ response: 'Test response' });
 			const mockPromptTemplate = new PromptTemplate({
 				template: '{query}',
@@ -377,7 +387,11 @@ describe('chainExecutor', () => {
 			});
 
 			expect(mockContext.getExecutionCancelSignal).toHaveBeenCalled();
-			expect(mockChain.invoke).toHaveBeenCalled();
+			// Signal must be in the config (2nd arg), NOT bundled in the input (1st arg)
+			expect(mockChain.invoke).toHaveBeenCalledWith(
+				{ query: 'Hello' },
+				{ signal: abortController.signal },
+			);
 		});
 
 		it('should support chat models', async () => {