Cannot read properties of null (reading 'length') when using self-hosted LLM

Questions
1

Describe the problem/error/question

Cannot read properties of null (reading ‘length’) While n8n Using Self-Host LLM(vLLM)

What is the error message (if any)?

—Error msg of “AI agent“ node—

Cannot read properties of null (reading ‘length’)

{
“errorMessage”: “Cannot read properties of null (reading ‘length’)”,
“errorDetails”: {},
“n8nDetails”: {
“nodeName”: “AI Agent”,
“nodeType”: “@n8n/n8n-nodes-langchain.agent”,
“nodeVersion”: 2.2,
“time”: “2025/11/13 17:17:36”,
“n8nVersion”: “1.110.1 (Self Hosted)”,
“binaryDataMode”: “default”,
“stackTrace”: [
“NodeOperationError: Cannot read properties of null (reading ‘length’)”,
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_14bc3da30a9a435c3a13115bcaf30796/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V2/execute.ts:305:12",
" at Array.forEach ()“,
" at ExecuteContext.toolsAgentExecute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_14bc3da30a9a435c3a13115bcaf30796/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V2/execute.ts:294:16)”,
" at processTicksAndRejections (node:internal/process/task_queues:105:5)“,
" at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_14bc3da30a9a435c3a13115bcaf30796/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/V2/AgentV2.node.ts:131:10)”,
" at WorkflowExecute.executeNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1254:8)“,
" at WorkflowExecute.runNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1428:11)”,
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1760:27",
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:2337:11"
]
}
}

Please share your workflow

Share the output returned by the last node

Cannot read properties of null (reading ‘length’)
{
“errorMessage”: “Cannot read properties of null (reading ‘length’)”,
“errorDetails”: {},
“n8nDetails”: {
“nodeName”: “AI Agent”,
“nodeType”: “@n8n/n8n-nodes-langchain.agent”,
“nodeVersion”: 2.2,
“time”: “2025/11/13 17:17:36”,
“n8nVersion”: “1.110.1 (Self Hosted)”,
“binaryDataMode”: “default”,
“stackTrace”: [
“NodeOperationError: Cannot read properties of null (reading ‘length’)”,
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_14bc3da30a9a435c3a13115bcaf30796/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V2/execute.ts:305:12",
" at Array.forEach ()“,
" at ExecuteContext.toolsAgentExecute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_14bc3da30a9a435c3a13115bcaf30796/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V2/execute.ts:294:16)”,
" at processTicksAndRejections (node:internal/process/task_queues:105:5)“,
" at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_14bc3da30a9a435c3a13115bcaf30796/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/V2/AgentV2.node.ts:131:10)”,
" at WorkflowExecute.executeNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1254:8)“,
" at WorkflowExecute.runNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1428:11)”,
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1760:27",
" at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@[email protected]_@[email protected]_5aee33ef851c7de341eb325c6a25e0ff/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:2337:11"
]
}
}

Information on your n8n setup

  • n8n version:
  • Database (default: SQLite):
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app):
  • Operating system:
2

I used this for my test environment, it runs well.
When copied to air-gapped environment A which using local LLM (Qwen32B), it also runs well,
but copied to air-gapped environment B which using local LLM (still Qwen32B), it failed, the error msg attached above.

1 Like
3

I followed the issue thread, tracing back to Sep 17. Fix got released with [email protected]. Try upgrading your n8n to newer versions.