{
"id": "yCIEiv9QUHP8pNfR",
"meta": {
"instanceId": "f29695a436689357fd2dcb55d528b0b528d2419f53613c68c6bf909a92493614",
"templateCredsSetupCompleted": true
},
"name": "Build Custom AI Agent with LangChain & Gemini (Self-Hosted)",
"tags": [
{
"id": "7M5ZpGl3oWuorKpL",
"name": "share",
"createdAt": "2025-03-26T01:17:15.342Z",
"updatedAt": "2025-03-26T01:17:15.342Z"
}
],
"nodes": [
{
"id": "8bd5382d-f302-4e58-b377-7fc5a22ef994",
"name": "When chat message received",
"type": "@n8n\/n8n-nodes-langchain.chatTrigger",
"position": [
-220,
0
],
"webhookId": "b8a5d72c-4172-40e8-b429-d19c2cd6ce54",
"parameters": {
"public": true,
"options": {
"responseMode": "lastNode",
"allowedOrigins": "*",
"loadPreviousSession": "memory"
},
"initialMessages": ""
},
"typeVersion": 1.100000000000000088817841970012523233890533447265625
},
{
"id": "6ae8a247-4077-4569-9e2c-bb68bcecd044",
"name": "Google Gemini Chat Model",
"type": "@n8n\/n8n-nodes-langchain.lmChatGoogleGemini",
"position": [
80,
240
],
"parameters": {
"options": {
"temperature": 0.6999999999999999555910790149937383830547332763671875,
"safetySettings": {
"values": [
{
"category": "HARM_CATEGORY_SEXUALLY_EXPLICIT",
"threshold": "BLOCK_NONE"
}
]
}
},
"modelName": "models\/gemini-2.0-flash-exp"
},
"credentials": {
"googlePalmApi": {
"id": "UEjKMw0oqBTAdCWJ",
"name": "Google Gemini(PaLM) Api account"
}
},
"typeVersion": 1
},
{
"id": "bbe6dcfa-430f-43f9-b0e9-3cf751b98818",
"name": "Sticky Note",
"type": "n8n-nodes-base.stickyNote",
"position": [
380,
-240
],
"parameters": {
"width": 260,
"height": 220,
"content": "\ud83d\udc47 **Prompt Engineering**\n - Define agent personality and conversation structure in the `Construct & Execute LLM Prompt` node's template variable \n - \u26a0\ufe0f Template must preserve `{chat_history}` and `{input}` placeholders for proper LangChain operation "
},
"typeVersion": 1
},
{
"id": "892a431a-6ddf-47fc-8517-1928ee99c95b",
"name": "Store conversation history",
"type": "@n8n\/n8n-nodes-langchain.memoryBufferWindow",
"position": [
280,
240
],
"parameters": [],
"notesInFlow": false,
"typeVersion": 1.3000000000000000444089209850062616169452667236328125
},
{
"id": "f9a22dbf-cac7-4d70-85b3-50c44a2015d5",
"name": "Construct & Execute LLM Prompt",
"type": "@n8n\/n8n-nodes-langchain.code",
"position": [
380,
0
],
"parameters": {
"code": {
"execute": {
"code": "const { PromptTemplate } = require('@langchain\/core\/prompts');\nconst { ConversationChain } = require('langchain\/chains');\nconst { BufferMemory } = require('langchain\/memory');\n\nconst template = `\nYou'll be roleplaying as the user's girlfriend. Your character is a woman with a sharp wit, logical mindset, and a charmingly aloof demeanor that hides your playful side. You're passionate about music, maintain a fit and toned physique, and carry yourself with quiet self-assurance. Career-wise, you're established and ambitious, approaching life with positivity while constantly striving to grow as a person.\n\nThe user affectionately calls you \"Bunny,\" and you refer to them as \"Darling.\"\n\nEssential guidelines:\n1. Respond exclusively in Chinese\n2. Never pose questions to the user - eliminate all interrogative forms\n3. Keep responses brief and substantive, avoiding rambling or excessive emojis\n\nContext framework:\n- Conversation history: {chat_history}\n- User's current message: {input}\n\nCraft responses that feel authentic to this persona while adhering strictly to these parameters.\n`;\n\nconst prompt = new PromptTemplate({\n template: template,\n inputVariables: [\"input\", \"chat_history\"], \n});\n\nconst items = this.getInputData();\nconst model = await this.getInputConnectionData('ai_languageModel', 0);\nconst memory = await this.getInputConnectionData('ai_memory', 0);\nmemory.returnMessages = false;\n\nconst chain = new ConversationChain({ llm:model, memory:memory, prompt: prompt, inputKey:\"input\", outputKey:\"output\"});\nconst output = await chain.call({ input: items[0].json.chatInput});\n\nreturn output;\n"
}
},
"inputs": {
"input": [
{
"type": "main",
"required": true,
"maxConnections": 1
},
{
"type": "ai_languageModel",
"required": true,
"maxConnections": 1
},
{
"type": "ai_memory",
"required": true,
"maxConnections": 1
}
]
},
"outputs": {
"output": [
{
"type": "main"
}
]
}
},
"retryOnFail": false,
"typeVersion": 1
},
{
"id": "fe104d19-a24d-48b3-a0ac-7d3923145373",
"name": "Sticky Note1",
"type": "n8n-nodes-base.stickyNote",
"position": [
-240,
-260
],
"parameters": {
"color": 5,
"width": 420,
"height": 240,
"content": "### Setup Instructions \n1. **Configure Gemini Credentials**: Set up your Google Gemini API key ([Get API key here](https:\/\/ai.google.dev\/) if needed). Alternatively, you may use other AI provider nodes. \n2. **Interaction Methods**: \n - Test directly in the workflow editor using the \"Chat\" button \n - Activate the workflow and access the chat interface via the URL provided by the `When Chat Message Received` node "
},
"typeVersion": 1
},
{
"id": "f166214d-52b7-4118-9b54-0b723a06471a",
"name": "Sticky Note2",
"type": "n8n-nodes-base.stickyNote",
"position": [
-220,
160
],
"parameters": {
"height": 100,
"content": "\ud83d\udc46 **Interface Settings**\nConfigure chat UI elements (e.g., title) in the `When Chat Message Received` node "
},
"typeVersion": 1
},
{
"id": "da6ca0d6-d2a1-47ff-9ff3-9785d61db9f3",
"name": "Sticky Note3",
"type": "n8n-nodes-base.stickyNote",
"position": [
20,
420
],
"parameters": {
"width": 200,
"height": 140,
"content": "\ud83d\udc46 **Model Selection**\nSwap language models through the `language model` input field in `Construct & Execute LLM Prompt` "
},
"typeVersion": 1
},
{
"id": "0b4dd1ac-8767-4590-8c25-36cba73e46b6",
"name": "Sticky Note4",
"type": "n8n-nodes-base.stickyNote",
"position": [
240,
420
],
"parameters": {
"width": 200,
"height": 140,
"content": "\ud83d\udc46 **Memory Control**\nAdjust conversation history length in the `Store Conversation History` node "
},
"typeVersion": 1
}
],
"active": false,
"pinData": [],
"settings": {
"callerPolicy": "workflowsFromSameOwner",
"executionOrder": "v1",
"saveManualExecutions": false,
"saveDataSuccessExecution": "none"
},
"versionId": "77cd5f05-f248-442d-86c3-574351179f26",
"connections": {
"Google Gemini Chat Model": {
"ai_languageModel": [
[
{
"node": "Construct & Execute LLM Prompt",
"type": "ai_languageModel",
"index": 0
}
]
]
},
"Store conversation history": {
"ai_memory": [
[
{
"node": "Construct & Execute LLM Prompt",
"type": "ai_memory",
"index": 0
},
{
"node": "When chat message received",
"type": "ai_memory",
"index": 0
}
]
]
},
"When chat message received": {
"main": [
[
{
"node": "Construct & Execute LLM Prompt",
"type": "main",
"index": 0
}
]
]
},
"Construct & Execute LLM Prompt": {
"main": [
[]
],
"ai_memory": [
[]
]
}
}
}
