Custom LangChain agent written in JavaScript
Needs changesNeeds changes. This template uses 2 thing(s) that n8n 3.0 removes: LangChain Code (legacy), AI Agent v1 (old agent modes). 2 breaking item(s) found. Static check, last run 2026-10-19.
What this workflow does
This AI workflow has 8 nodes and runs manually, when you click “Execute workflow”. Along the way it connects OpenAI Chat Model.
How it runs
Trigger: Manually, when you click “Execute workflow”.
- Set (Edit Fields (Set)): sets 1 field: chatInput
- Set (Edit Fields (Set)): sets 1 field: chatInput
- AI Agent: runs an AI agent, with model: OpenAI Chat Model; 1 tool (Custom - Wikipedia)
- Custom - LLM Chain Node (LangChain Code): uses LangChain Code, with model: OpenAI Chat Model
Services it uses
Before you upgrade to n8n 3.0
2 things in this workflow are removed in n8n 3.0. Fix them before you upgrade:
- LangChain Code (legacy) in Custom - LLM Chain Node1: no direct replacement.
- AI Agent v1 (old agent modes) in AI Agent (v1.8): replace with Latest AI Agent node (Tools Agent). For SQL Agent, use a Postgres or MySQL tool with a recent AI Agent.
Rather not rewrite it? Many of these flows can be rebuilt in Make (free plan).
| Removed in 3.0 | Replace with |
|---|---|
| LangChain Code (legacy) Custom - LLM Chain Node1 | No direct replacement |
| AI Agent v1 (old agent modes) AI Agent (v1.8) | Latest AI Agent node (Tools Agent). For SQL Agent, use a Postgres or MySQL tool with a recent AI Agent. |
Nodes used (6)
- Manual Trigger
n8n-nodes-base.manualTrigger - Edit Fields (Set)
n8n-nodes-base.set - LangChain Code
@n8n/n8n-nodes-langchain.code - OpenAI Chat Model
@n8n/n8n-nodes-langchain.lmChatOpenAi - AI Agent
@n8n/n8n-nodes-langchain.agent - Code Tool
@n8n/n8n-nodes-langchain.toolCode
From the author
This workflow has multiple functionalities. It starts with a manual trigger, "When clicking 'Execute Workflow'", that activates two separate paths. The first path takes a preset string "Tell me a joke" and processes it through a custom Language Learning Model…