Build custom AI agent with LangChain & Gemini (self-hosted)

Overview This workflow leverages the LangChain code node to implement a fully customizable conversational agent. Ideal for users who need granular control over their agent's prompts while reducing unnecessary token consumption from reserved tool-calling functionality (compared to n8n's built-in Conversation Agent). 

Setup Instructions 1. 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. 2. Interaction Methods: - Test directly in the workflow editor using the "Chat" button - Activate the workflow and access the chat interface via the URL provided by the When Chat Message Received node

Customization Options 1. Interface Settings: Configure chat UI elements (e.g., title) in the When Chat Message Received node 2. Prompt Engineering: - Define agent personality and conversation structure in the Construct & Execute LLM Prompt node's template variable - ⚠️ Template must preserve {chathistory} and {input} placeholders for proper LangChain operation 3. Model Selection: Swap language models through the language model input field in Construct & Execute LLM Prompt 4. Memory Control: Adjust conversation history length in the Store Conversation History node

Requirements: ⚠️ This workflow uses the LangChain Code node, which only works on self-hosted n8n. (Refer to [LangChain Code node docs](https://docs.n8n.io/integrations/builtin/cluster-nodes/root-nodes/n8n-nodes-langchain.code/))