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CopilotKit <> LangGraph Starter

examples/v2/interrupts-langgraph/README.md

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CopilotKit <> LangGraph Starter

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

.
ā”œā”€ā”€ apps/
│   ā”œā”€ā”€ 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

  1. Install all dependencies (this installs everything for both apps):
bash
pnpm install
  1. Set up your OpenAI API key by copying the example env file and editing it:
bash
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.

  1. Start the development servers:
bash
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:

bash
# 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/.

šŸ“š Documentation

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