copilotkit--copilotkit/showcase/integrations/built-in-agent

Built-in Agent (TanStack AI) Showcase

CopilotKit's BuiltInAgent in factory mode with TanStack AI as the LLM backend.

The agent runs in-process inside the Next.js API route — there is no separate agent server process to start (unlike the LangGraph TypeScript variant which spawns langgraph-cli on port 8123).

Quick Start

Prerequisites

• Node.js 18+
• An OpenAI API key

Setup

1. Clone & install dependencies

npm install

2. Set environment variables

Create a .env.local file from .env.example:

cp .env.example .env.local

Then fill in your OPENAI_API_KEY:

OPENAI_API_KEY=sk-...
NEXT_PUBLIC_COPILOTKIT_AGENT=default

3. Start the dev server

npm run dev

Open http://localhost:3000 to see the demo index.

Build

npm run build

Architecture

• Agent Factory: See src/lib/factory/tanstack-factory.ts for the BuiltInAgent wiring and TanStack AI integration.
• Tools: Defined in:
  • src/lib/factory/state-tools.ts — state management tools
  • src/lib/factory/server-tools.ts — server-side tools
  • src/lib/factory/subagent-tools.ts — sub-agent tools
• API Route: src/app/api/copilotkit/[[...slug]]/route.ts handles the AG-UI protocol.

Next Steps

Phase 3+ will add individual demo pages under src/app/demos/.