This is a starter template for building AI agents using LangGraph and CopilotKit. It provides a modern Next.js application with an integrated LangGraph agent to be built on top of.

This project is organized as a monorepo using pnpm workspaces.

Project Structure

.
├── apps/
│   ├── web/          # Next.js frontend application
│   └── agent/        # LangGraph agent
└── package.json      # pnpm workspaces via pnpm-workspace.yaml

Prerequisites

Node.js 20+
pnpm 9.15.0 or later
OpenAI API Key (for the LangGraph agent)

Getting Started

Install all dependencies (this installs everything for both apps):

pnpm install

Set up your OpenAI API key by copying the example env file and editing it:

cp apps/agent/.env.example apps/agent/.env

Then open apps/agent/.env in your editor and fill in OPENAI_API_KEY with your key.

For production, also copy apps/web/.env.example to apps/web/.env and set LANGGRAPH_DEPLOYMENT_URL to your deployed agent URL.

Start the development servers:

pnpm dev

This will start both the Next.js app (on port 3000) and the LangGraph agent (on port 8125) via Turbo (installed as a dev dependency).

Available Scripts

All scripts use Turbo to run tasks across the workspace:

pnpm dev - Starts both the web app and agent servers in development mode
pnpm build - Builds all apps for production
pnpm lint - Runs linting across all apps

Running Scripts for Individual Apps

You can also run scripts for individual apps using pnpm's filter flag:

# Run dev for just the web app
pnpm --filter web-langgraph-interrupt dev

# Run dev for just the agent
pnpm --filter agent-langgraph-interrupt dev

# Or navigate to the app directory
cd apps/web
pnpm dev

Customization

The main UI component is in apps/web/src/app/page.tsx. You can:

Modify the theme colors and styling
Add new frontend actions
Utilize shared-state
Customize your user-interface for interacting with LangGraph

The LangGraph agent code is in apps/agent/src/.

📚 Documentation

CopilotKit Documentation - Explore CopilotKit's capabilities
LangGraph Documentation - Learn more about LangGraph and its features
Next.js Documentation - Learn about Next.js features and API

Contributing

Feel free to submit issues and enhancement requests! This starter is designed to be easily extensible.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Troubleshooting

Agent Connection Issues

If the chat returns an "Internal error while dispatching CopilotKit request" 500: Check the Next.js server logs for [copilotkit/route] runtime construction failed: or [copilotkit/route] handleRequest dispatch failed:. Common causes:

LANGGRAPH_DEPLOYMENT_URL unset in production (required — check apps/web/.env)
LangGraph server not running at the configured URL (check pnpm --filter agent-langgraph-interrupt dev started cleanly)
OPENAI_API_KEY missing from apps/agent/.env