mcp-agent-langchainjs

<div align="center"> <img src="./packages/agent-webapp/public/favicon.png" alt="" align="center" height="64" /> # AI Agent with MCP tools using LangChain.js [](https://codespaces.new/Azure-Samples/mcp-agent-langchainjs?hide_repo_select=true&ref=main&quickstart=true) [](https://aka.ms/foundry/discord) [](#deploy-to-azure) <br> [](https://github.com/Azure-Samples/mcp-agent-langchainjs/actions) [](https://dev.to/azure/serverless-mcp-agent-with-langchainjs-v1-burgers-tools-and-traces-25oo)  [](https://www.typescriptlang.org) [](LICENSE) ⭐ If you like this sample, star it on GitHub — it helps a lot! [Overview](#overview) • [Architecture](#architecture) • [Getting started](#getting-started) • [Deploy to Azure](#deploy-to-azure) • [Run locally](#run-locally) • [MCP tools](#mcp-tools) • [Resources](#resources)  </div> ## Overview This project demonstrates how to build AI agents that can interact with real-world APIs using the **Model Context Protocol (MCP)**. It features a complete burger ordering system with a serverless API, web interfaces, and an MCP server that enables AI agents to browse menus, place orders, and track order status. The agent uses **LangChain.js** to handle LLM reasoning and tool calling. The system consists of multiple interconnected services, as detailed in the [Architecture](#architecture) section below. The system is hosted on [Azure Static Web Apps](https://learn.microsoft.com/azure/static-web-apps/overview) (web apps) and [Azure Functions](https://learn.microsoft.com/azure/azure-functions/functions-overview?pivots=programming-language-javascript) (API and MCP servers), with [Azure Cosmos DB for NoSQL](https://learn.microsoft.com/azure/cosmos-db/nosql/) for data storage. You can use it as a starting point for building your own AI agents. <!-- > [!TIP] > You can test this application locally without deployment needed or any cloud costs. The MCP server works with popular AI tools like GitHub Copilot, Claude, and other MCP-compatible clients. --> ### Key features - LangChain.js agent with tool calling via MCP (Streamable HTTP transport) - Multi-service, end‑to‑end architecture (web UIs, APIs, MCP server) - User authentication with sessions history - 100% serverless architecture, for cost-effective scaling - Single-command deployment using Infrastructure as Code (IaC) ## Architecture Building AI applications can be complex and time-consuming, but using LangChain.js and Azure serverless technologies allows to greatly simplify the process. This application is a AI agent that can be access through different interfaces (web app, CLI) and that can call tools through MCP to interact with a burger ordering API.  The application is made from these main components: | Component | Folder | Purpose | | ----------------- | ---------------------------------------------------- | -------------------------------------------- | | Agent Web App | [`packages/agent-webapp`](./packages/agent-webapp) | Chat interface + conversation rendering | | Agent API | [`packages/agent-api`](./packages/agent-api) | LangChain.js agent + chat state + MCP client | | Burger API | [`packages/burger-api`](./packages/burger-api) | Core burger & order management web API | | Burger MCP Server | [`packages/burger-mcp`](./packages/burger-mcp) | Exposes burger API as MCP tools | | Burger Web App | [`packages/burger-webapp`](./packages/burger-webapp) | Live orders visualization | | Infrastructure | [`infra`](./infra) | Bicep templates (IaC) | Additionally, these support components are included: | Component | Folder | Purpose | | --------------- | ------------------------------------------------ | -------------------------------------------------------- | | Agent CLI | [`packages/agent-cli`](./packages/agent-cli) | Command-line interface LangChain.js agent and MCP client | | Data generation | [`packages/burger-data`](./packages/burger-data) | Scripts to (re)generate burgers data & images | ## Getting started There are multiple ways to get started with this project. The quickest way is to use [GitHub Codespaces](#use-github-codespaces) that provides a preconfigured environment for you. Alternatively, you can [set up your local environment](#use-your-local-environment) following the instructions below. <details open> <summary><h3>Use GitHub Codespaces</h3></summary> You can run this project directly in your browser by using GitHub Codespaces, which will open a web-based VS Code: [](https://codespaces.new/Azure-Samples/mcp-agent-langchainjs?hide_repo_select=true&ref=main&quickstart=true) </details> <details> <summary><h3>Use a VSCode dev container</h3></summary> A similar option to Codespaces is VS Code Dev Containers, that will open the project in your local VS Code instance using the [Dev Containers extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers). You will also need to have [Docker](https://www.docker.com/get-started/) installed on your machine to run the container. [](https://vscode.dev/redirect?url=vscode://ms-vscode-remote.remote-containers/cloneInVolume?url=https://github.com/Azure-Samples/mcp-agent-langchainjs) </details> <details> <summary><h3>Use your local environment</h3></summary> You need to install following tools to work on your local machine: - [Node.js LTS](https://nodejs.org/en/download) - [Azure Developer CLI 1.19+](https://aka.ms/azure-dev/install) - [Git](https://git-scm.com/downloads) - [PowerShell 7+](https://github.com/powershell/powershell) _(for Windows users only)_ - **Important**: Ensure you can run `pwsh.exe` from a PowerShell command. If this fails, you likely need to upgrade PowerShell. - Instead of Powershell, you can also use Git Bash or WSL to run the Azure Developer CLI commands. Then you can get the project code: 1. [**Fork**](https://github.com/Azure-Samples/mcp-agent-langchainjs/fork) the project to create your own copy of this repository. 2. On your forked repository, select the **Code** button, then the **Local** tab, and copy the URL of your forked repository.  3. Open a terminal and run this command to clone the repo: `git clone <your-repo-url>` </details> ## Deploy to Azure ### Prerequisites - **Azure account**: If you're new to Azure, [get an Azure account for free](https://azure.microsoft.com/free) to get free Azure credits to get started - **Azure account permissions**: Your Azure account must have `Microsoft.Authorization/roleAssignments/write` permissions, such as [Role Based Access Control Administrator](https://learn.microsoft.com/azure/role-based-access-control/built-in-roles#role-based-access-control-administrator-preview), [User Access Administrator](https://learn.microsoft.com/azure/role-based-access-control/built-in-roles#user-access-administrator), or [Owner](https://learn.microsoft.com/azure/role-based-access-control/built-in-roles#owner) ### Deploy with Azure Developer CLI 1. Open a terminal and navigate to the root of the project 2. Authenticate with Azure by running `azd auth login` 3. Run `azd up` to deploy the application to Azure. This will provision Azure resources and deploy all services - You will be prompted to select a base location for the resources - The deployment process will take a few minutes Once deployment is complete, you'll see the URLs of all deployed services in the terminal. ### Cost estimation Pricing varies per region and usage, so it isn't possible to predict exact costs for your usage. However, you can use the Azure pricing calculator with pre-configured estimations to get an idea of the costs: [Azure Pricing Calculator](https://azure.com/e/0ddf5e6a4c654576a74b7199c85413b9). ### Clean up resources To clean up all the Azure resources created by this sample: ```bash azd down --purge ``` ## Run locally After setting up your environment and provisioned the Azure resources, you can run the entire application locally: ```bash # Install dependencies for all services npm install # Start all services locally npm start ``` Starting the different services may take some time, you need to wait until you see the following message in the terminal: `🚀 All services ready 🚀` This will start: - **Agent Web App**: http://localhost:4280 - **Agent API**: http://localhost:7072 - **Burger Web App**: http://localhost:5173 - **Burger API**: http://localhost:7071 - **Burger MCP Server**: http://localhost:3000 > [!NOTE] > When running locally without having deployed the application, the servers will use in-memory storage, so any data will be lost when you stop the servers. > After a successful deployment, the servers will use Azure Cosmos DB for persistent storage. You can then open the Agent web app and ask things like: - _What spicy burgers do you have?_ - _Order two Classic Cheeseburgers with extra bacon._ - _Show my recent orders_ The agent will decide which MCP tool(s) to call, then come up with a response. ### Available scripts This project uses [npm workspaces](https://docs.npmjs.com/cli/v9/using-npm/workspaces) to manage multiple packages in a single repository. You can run scripts from the root folder that will apply to all packages, or you can run scripts for individual packages as indicated in their respective README files. Common scripts (run from repo root): | Action | Command | | ---------------- | ------------------ | | Start everything | `npm start` | | Build all | `npm run build` | | Lint | `npm run lint` | | Fix lint | `npm run lint:fix` | | Format | `npm run format` | ## MCP tools The Burger MCP server provides these tools for AI agents: | Tool Name | Description | | ------------------------ | -------------------------------------------------------------------------------------------- | | `get_burgers` | Get a list of all burgers in the menu | | `get_burger_by_id` | Get a specific burger by its ID | | `get_toppings` | Get a list of all toppings in the menu | | `get_topping_by_id` | Get a specific topping by its ID | | `get_topping_categories` | Get a list of all topping categories | | `get_orders` | Get a list of all orders in the system | | `get_order_by_id` | Get a specific order by its ID | | `place_order` | Place a new order with burgers (requires `userId`, optional `nickname`) | | `delete_order_by_id` | Cancel an order if it has not yet been started (status must be `pending`, requires `userId`) | ### Testing the MCP Server #### Using the MCP Inspector You can test the MCP server using the MCP Inspector: 1. Install and start MCP Inspector: ```bash npx -y @modelcontextprotocol/inspector ``` 2. In your browser, open the MCP Inspector (the URL will be shown in the terminal) 3. Configure the connection: - **Transport**: Streamable HTTP - **URL**: `http://localhost:3000/mcp` 4. Click **Connect** and explore the available tools #### Using GitHub Copilot To use the MCP server in local mode with GitHub Copilot, create a local `.vscode/mcp.json` configuration file in your project root: ```json { "servers": { "burger-mcp": { "type": "stdio", "command": "npm", "args": ["run", "start:local", "--workspace=burger-mcp"] } } } ``` If you open that file Then, you can use GitHub Copilot in **agent mode** to interact with the MCP server. For example, you can ask questions like "What burgers are available?" or "Place an order for a vegan burger" and Copilot will use the MCP server to provide answers or perform actions. > [!TIP] > Copilot models can behave differently regarding tools usage, so if you don't see it calling the `burger-mcp` tools, you can explicitly mention using the Bruger MCP server by adding `#burger-mcp` in your prompt. ## Resources Here are some resources to learn more about the technologies used in this project: - [Model Context Protocol](https://modelcontextprotocol.io/) - More about the MCP protocol - [MCP for Beginners](https://github.com/microsoft/mcp-for-beginners) - A beginner-friendly introduction to MCP - [Generative AI with JavaScript](https://github.com/microsoft/generative-ai-with-javascript) - Learn how to build Generative AI applications with JavaScript - [Azure AI Travel Agents with Llamaindex.TS and MCP](https://github.com/Azure-Samples/azure-ai-travel-agents/) - Sample for building AI agents using Llamaindex.TS and MCP - [Serverless AI Chat with RAG using LangChain.js](https://github.com/Azure-Samples/serverless-chat-langchainjs) - Sample for building a serverless AI chat grounded on your own data with LangChain.js You can also find [more Azure AI samples here](https://github.com/Azure-Samples/azureai-samples). ## Troubleshooting If you encounter issues while running or deploying this sample: 1. **Dependencies**: Ensure all required tools are installed and up to date 2. **Ports**: Make sure required ports (3000, 4280, 5173, 5174, 7071, 7072) are not in use 3. **Azure Developer CLI**: Verify you're authenticated with `azd auth login` 4. **Node.js version**: Ensure you're using Node.js 22 or higher For more detailed troubleshooting, check the individual README files in each service directory. ## Built for AI Agents This project has been optimized for use with AI agents like [GitHub Copilot](https://github.com/features/copilot). This includes: - Built-in context engineering provided with [AGENTS.md](https://agents.md/) files to help AI agents understand and extend the codebase. - [Reusable prompts](./.github/prompts/) for common tasks. - [Custom instructions](./.github/instructions/) tailored for each service of the project. - Custom **Codebase Explorer** chat mode for Copilot, to help you explore and understand the codebase. To learn how to set up and use GitHub Copilot with this repository, check out the [docs/copilot.md](./docs/copilot.md) guide. ## Getting Help If you get stuck or have any questions about building AI apps, join: [](https://aka.ms/foundry/discord) If you have product feedback or errors while building visit: [](https://aka.ms/foundry/forum)