Built-in Agent

The Built-in Agent is the simplest agent backend CopilotKit ships. Instead of proxying to an external framework process (LangGraph, Mastra, etc.), it instantiates BuiltInAgent({ model, tools, prompt }) inside your runtime and runs the agent loop in-process. No separate agent server, no external framework install — direct connection to OpenAI / Anthropic / Google or any AI-SDK model with full support for tools, generative UI, and shared state.

For the full BIA-scoped guides — quickstart, server tools, MCP servers, model selection, advanced configuration — see /built-in-agent.