LangChain - Example - Code Node Example
Explore a basic LangChain agent that answers questions using a custom tool. This workflow connects n8n's AI nodes and custom code nodes to OpenAI for language model interactions. It's useful for developers building custom AI assistants or researchers experimenting with agentic workflows. This saves development time by providing a ready-to-use example of a LangChain agent.
Workflow JSON
{"id": "q2MJWAqpKF2BCJkq", "meta": {"instanceId": "021d3c82ba2d3bc090cbf4fc81c9312668bcc34297e022bb3438c5c88a43a5ff"}, "name": "LangChain - Example - Code Node Example", "tags": [{"id": "snf16n0p2UrGP838", "name": "LangChain - Example", "createdAt": "2023-09-25T16:21:55.962Z", "updatedAt": "2023-09-25T16:21:55.962Z"}], "nodes": [{"id": "ad1a920e-1048-4b58-9c4a-a0469a1f189d", "name": "OpenAI", "type": "@n8n/n8n-nodes-langchain.lmOpenAi", "position": [900, 628], "parameters": {"options": {}}, "credentials": {"openAiApi": {"id": "", "name": "[Your openAiApi]"}}, "typeVersion": 1}, {"id": "7dd04ecd-f169-455c-9c90-140140e37542", "name": "Sticky Note", "type": "n8n-nodes-base.stickyNote", "position": [800, 340], "parameters": {"width": 432, "height": 237, "content": "## Self-coded LLM Chain Node"}, "typeVersion": 1}, {"id": "05ad7d68-5dc8-42f2-8274-fcb5bdeb68cb", "name": "When clicking \"Execute Workflow\"", "type": "n8n-nodes-base.manualTrigger", "position": [280, 428], "parameters": {}, "typeVersion": 1}, {"id": "39e2fd34-3261-44a1-aa55-96f169d55aad", "name": "Set", "type": "n8n-nodes-base.set", "position": [620, 428], "parameters": {"values": {"string": [{"name": "input", "value": "Tell me a joke"}]}, "options": {}}, "typeVersion": 2}, {"id": "42a3184c-0c62-4e79-9220-7a93e313317e", "name": "Set1", "type": "n8n-nodes-base.set", "position": [620, 820], "parameters": {"values": {"string": [{"name": "input", "value": "What year was Einstein born?"}]}, "options": {}}, "typeVersion": 2}, {"id": "4e2af29d-7fc4-484b-8028-1b9a84d60172", "name": "Chat OpenAI", "type": "@n8n/n8n-nodes-langchain.lmChatOpenAi", "position": [731, 1108], "parameters": {"options": {}}, "credentials": {"openAiApi": {"id": "", "name": "[Your openAiApi]"}}, "typeVersion": 1}, {"id": "334e9176-3a18-4838-84cb-70e8154f1a30", "name": "Sticky Note1", "type": "n8n-nodes-base.stickyNote", "position": [880, 1028], "parameters": {"width": 320.2172923777021, "height": 231, "content": "## Self-coded Tool Node"}, "typeVersion": 1}, {"id": "05e0d5c6-df18-42ba-99b6-a2b65633a14d", "name": "Custom - Wikipedia", "type": "@n8n/n8n-nodes-langchain.code", "position": [971, 1108], "parameters": {"code": {"supplyData": {"code": "console.log('Custom Wikipedia Node runs');\nconst { WikipediaQueryRun } = require('langchain/tools');\nreturn new WikipediaQueryRun();"}}, "outputs": {"output": [{"type": "ai_tool"}]}}, "typeVersion": 1}, {"id": "9c729e9a-f173-430c-8bcd-74101b614891", "name": "Custom - LLM Chain Node", "type": "@n8n/n8n-nodes-langchain.code", "position": [880, 428], "parameters": {"code": {"execute": {"code": "const { PromptTemplate } = require('langchain/prompts');\n\nconst query = $input.item.json.input;\nconst prompt = PromptTemplate.fromTemplate(query);\nconst llm = await this.getInputConnectionData('ai_languageModel', 0);\nlet chain = prompt.pipe(llm);\nconst output = await chain.invoke();\nreturn [ {json: { output } } ];"}}, "inputs": {"input": [{"type": "main"}, {"type": "ai_languageModel", "required": true, "maxConnections": 1}]}, "outputs": {"output": [{"type": "main"}]}}, "typeVersion": 1}, {"id": "6427bbf0-49a6-4810-9744-87d88151e914", "name": "Agent", "type": "@n8n/n8n-nodes-langchain.agent", "position": [880, 820], "parameters": {"options": {}}, "typeVersion": 1}], "active": false, "pinData": {}, "settings": {"executionOrder": "v1"}, "versionId": "e14a709d-08fe-4ed7-903a-fb2bae80b28a", "connections": {"Set": {"main": [[{"node": "Custom - LLM Chain Node", "type": "main", "index": 0}]]}, "Set1": {"main": [[{"node": "Agent", "type": "main", "index": 0}]]}, "OpenAI": {"ai_languageModel": [[{"node": "Custom - LLM Chain Node", "type": "ai_languageModel", "index": 0}]]}, "Chat OpenAI": {"ai_languageModel": [[{"node": "Agent", "type": "ai_languageModel", "index": 0}]]}, "Custom - Wikipedia": {"ai_tool": [[{"node": "Agent", "type": "ai_tool", "index": 0}]]}, "When clicking \"Execute Workflow\"": {"main": [[{"node": "Set", "type": "main", "index": 0}, {"node": "Set1", "type": "main", "index": 0}]]}}}How to Import This Workflow
- 1Copy the workflow JSON above using the Copy Workflow JSON button.
- 2Open your n8n instance and go to Workflows.
- 3Click Import from JSON and paste the copied workflow.
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