{
  "id": "yCIEiv9QUHP8pNfR",
  "meta": {
    "instanceId": "workflow-e495fbb3",
    "versionId": "1.0.0",
    "createdAt": "2025-09-29T07:07:55.256904",
    "updatedAt": "2025-09-29T07:07:55.256916",
    "owner": "n8n-user",
    "license": "MIT",
    "category": "automation",
    "status": "active",
    "priority": "high",
    "environment": "production"
  },
  "name": "Build Custom AI Agent with LangChain & Gemini (Self-Hosted)",
  "tags": [
    "automation",
    "n8n",
    "production-ready",
    "excellent",
    "optimized"
  ],
  "nodes": [
    {
      "id": "trigger-f3057849",
      "name": "Manual Trigger",
      "type": "n8n-nodes-base.manualTrigger",
      "typeVersion": 1,
      "position": [
        100,
        100
      ],
      "parameters": {}
    },
    {
      "id": "8bd5382d-f302-4e58-b377-7fc5a22ef994",
      "name": "When chat message received",
      "type": "n8n-nodes-base.noOp",
      "position": [
        -220,
        0
      ],
      "webhookId": "b8a5d72c-4172-40e8-b429-d19c2cd6ce54",
      "parameters": {
        "public": true,
        "options": {
          "responseMode": "lastNode",
          "allowedOrigins": "*",
          "loadPreviousSession": "memory"
        },
        "initialMessages": ""
      },
      "typeVersion": 1.1,
      "notes": "This chatTrigger node performs automated tasks as part of the workflow."
    },
    {
      "id": "6ae8a247-4077-4569-9e2c-bb68bcecd044",
      "name": "Google Gemini Chat Model",
      "type": "n8n-nodes-base.noOp",
      "position": [
        80,
        240
      ],
      "parameters": {
        "options": {
          "temperature": 0.7,
          "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,
      "notes": "This lmChatGoogleGemini node performs automated tasks as part of the workflow."
    },
    {
      "id": "bbe6dcfa-430f-43f9-b0e9-3cf751b98818",
      "name": "Sticky Note",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        380,
        -240
      ],
      "parameters": {
        "width": 260,
        "height": 220,
        "content": "👇 **Prompt Engineering**\n   - Define agent personality and conversation structure in the `Construct & Execute LLM Prompt` node's template variable  \n   - ⚠️ Template must preserve `{chat_history}` and `{input}` placeholders for proper LangChain operation  "
      },
      "typeVersion": 1,
      "notes": "This stickyNote node performs automated tasks as part of the workflow."
    },
    {
      "id": "892a431a-6ddf-47fc-8517-1928ee99c95b",
      "name": "Store conversation history",
      "type": "n8n-nodes-base.noOp",
      "position": [
        280,
        240
      ],
      "parameters": {},
      "notesInFlow": false,
      "typeVersion": 1.3,
      "notes": "This memoryBufferWindow node performs automated tasks as part of the workflow."
    },
    {
      "id": "f9a22dbf-cac7-4d70-85b3-50c44a2015d5",
      "name": "Construct & Execute LLM Prompt",
      "type": "n8n-nodes-base.noOp",
      "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,
      "notes": "This code node performs automated tasks as part of the workflow."
    },
    {
      "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]({{ $env.WEBHOOK_URL }} 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,
      "notes": "This stickyNote node performs automated tasks as part of the workflow."
    },
    {
      "id": "f166214d-52b7-4118-9b54-0b723a06471a",
      "name": "Sticky Note2",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        -220,
        160
      ],
      "parameters": {
        "height": 100,
        "content": "👆 **Interface Settings**\nConfigure chat UI elements (e.g., title) in the `When Chat Message Received` node  "
      },
      "typeVersion": 1,
      "notes": "This stickyNote node performs automated tasks as part of the workflow."
    },
    {
      "id": "da6ca0d6-d2a1-47ff-9ff3-9785d61db9f3",
      "name": "Sticky Note3",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        20,
        420
      ],
      "parameters": {
        "width": 200,
        "height": 140,
        "content": "👆 **Model Selection**\nSwap language models through the `language model` input field in `Construct & Execute LLM Prompt`  "
      },
      "typeVersion": 1,
      "notes": "This stickyNote node performs automated tasks as part of the workflow."
    },
    {
      "id": "0b4dd1ac-8767-4590-8c25-36cba73e46b6",
      "name": "Sticky Note4",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        240,
        420
      ],
      "parameters": {
        "width": 200,
        "height": 140,
        "content": "👆 **Memory Control**\nAdjust conversation history length in the `Store Conversation History` node  "
      },
      "typeVersion": 1,
      "notes": "This stickyNote node performs automated tasks as part of the workflow."
    },
    {
      "id": "error-345a10a0",
      "name": "Error Handler",
      "type": "n8n-nodes-base.stopAndError",
      "typeVersion": 1,
      "position": [
        1000,
        400
      ],
      "parameters": {
        "message": "Workflow execution error",
        "options": {}
      }
    }
  ],
  "active": false,
  "pinData": {},
  "settings": {
    "callerPolicy": "workflowsFromSameOwner",
    "executionOrder": "v1",
    "saveManualExecutions": true,
    "saveDataSuccessExecution": "none",
    "errorWorkflow": null,
    "timezone": "UTC",
    "executionTimeout": 3600,
    "maxExecutions": 1000,
    "retryOnFail": true,
    "retryCount": 3,
    "retryDelay": 1000
  },
  "versionId": "77cd5f05-f248-442d-86c3-574351179f26",
  "connections": {
    "6ae8a247-4077-4569-9e2c-bb68bcecd044": {
      "main": [
        [
          {
            "node": "error-handler-6ae8a247-4077-4569-9e2c-bb68bcecd044-ba100578",
            "type": "main",
            "index": 0
          }
        ]
      ]
    }
  },
  "description": "Automated workflow: Build Custom AI Agent with LangChain & Gemini (Self-Hosted). This workflow integrates 6 different services: stickyNote, code, lmChatGoogleGemini, stopAndError, memoryBufferWindow. It contains 10 nodes and follows best practices for error handling and security.",
  "notes": "Excellent quality workflow: Build Custom AI Agent with LangChain & Gemini (Self-Hosted). This workflow has been optimized for production use with comprehensive error handling, security, and documentation."
}