---
title: "API Reference"
description: "API Reference for the next-generation CopilotKit React API."
---

The v2 React API (`@copilotkit/react-core/v2`) is the next-generation interface for building copilot-powered applications. It provides a streamlined set of hooks and components built on top of the [AG-UI](https://docs.ag-ui.com) agent protocol.

## Provider Setup

The v2 API uses the [`<CopilotKit>`](/reference/components/CopilotKit) provider. Wrap your application with it to configure the runtime connection:

```tsx
import { CopilotKit } from "@copilotkit/react-core/v2";

function App() {
  return (
    <CopilotKit runtimeUrl="/api/copilotkit">
      <YourApp />
    </CopilotKit>
  );
}
```

<Accordions>
<Accordion title="Advanced: Using CopilotKit directly">

<Callout type="warn">
  `CopilotKit` is a low-level provider intended for advanced use cases. Most applications should use the `<CopilotKit>` component from `@copilotkit/react-core/v2` instead.
</Callout>

If you need direct control over the v2 provider (e.g. for custom integrations), import `CopilotKit` from `@copilotkit/react-core/v2`:

```tsx
import { CopilotKit } from "@copilotkit/react-core/v2";

<CopilotKit runtimeUrl="/api/copilotkit">
  <App />
</CopilotKit>
```

### Props

<PropertyReference name="runtimeUrl" type="string">
  URL of the CopilotKit runtime endpoint. Lazily forwarded to the core after
  mount.
</PropertyReference>

<PropertyReference name="headers" type="Record<string, string>" default="{}">
  Request headers forwarded with runtime calls.
</PropertyReference>

<PropertyReference name="credentials" type="RequestCredentials">
  Credentials mode for fetch requests (e.g. `"include"` for HTTP-only cookies in
  cross-origin requests).
</PropertyReference>

<PropertyReference name="publicApiKey" type="string">
  Copilot Cloud public API key.
</PropertyReference>

<PropertyReference name="publicLicenseKey" type="string">
  Alias for `publicApiKey`.
</PropertyReference>

<PropertyReference
  name="properties"
  type="Record<string, unknown>"
  default="{}"
>
  Runtime metadata payload.
</PropertyReference>

<PropertyReference name="useSingleEndpoint" type="boolean">
  When enabled, all runtime calls use a single endpoint.
</PropertyReference>

<PropertyReference
  name="agents__unsafe_dev_only"
  type="Record<string, AbstractAgent>"
>
  Preinstantiated agents for development/testing. **Not intended for production
  use.**
</PropertyReference>

<PropertyReference name="renderToolCalls" type="ReactToolCallRenderer[]">
  Static set of tool call renderers. The array should be stable across renders.
</PropertyReference>

<PropertyReference
  name="renderActivityMessages"
  type="ReactActivityMessageRenderer[]"
>
  Static set of activity message renderers.
</PropertyReference>

<PropertyReference
  name="renderCustomMessages"
  type="ReactCustomMessageRenderer[]"
>
  Static set of custom message renderers.
</PropertyReference>

<PropertyReference name="frontendTools" type="ReactFrontendTool[]">
  Static tool handlers defined at the provider level. The array should be stable
  across renders.
</PropertyReference>

<PropertyReference name="humanInTheLoop" type="ReactHumanInTheLoop[]">
  Declarative human-in-the-loop tool definitions. Each becomes both a tool
  handler and a tool call renderer.
</PropertyReference>

<PropertyReference name="showDevConsole" type='boolean | "auto"'>
  Show the CopilotKit developer console for debugging.
</PropertyReference>

<PropertyReference name="onError" type="(event: { error: Error; code: CopilotKitCoreErrorCode; context: Record<string, any> }) => void | Promise<void>">
  Error handler called when CopilotKit encounters an error. Fires for all error types: runtime connection failures, agent errors, and tool errors.

Unlike the v1 `onError`, this does **not** require a `publicApiKey` — error handling works with any configuration.

```tsx
<CopilotKit
  runtimeUrl="/api/copilotkit"
  onError={(event) => {
    console.error(`[${event.code}]`, event.error.message, event.context);
  }}
>
  <App />
</CopilotKit>
```

</PropertyReference>

</Accordion>
</Accordions>

## Styling

When using v2 UI components, import the stylesheet once at your app boundary:

```tsx
import "@copilotkit/react-core/v2/styles.css";
```

## API Reference

<Callout type="info">
  Looking for tool rendering hooks? Start with
  [`useComponent`](/reference/hooks/useComponent),
  [`useRenderTool`](/reference/hooks/useRenderTool), and
  [`useDefaultRenderTool`](/reference/hooks/useDefaultRenderTool).
</Callout>

<Cards>
  <Card
    title="Hooks"
    description="React hooks for agents, tools, context, and chat configuration."
    href="/reference/hooks/useAgent"
    icon={<LinkIcon />}
  />
  <Card
    title="UI Components"
    description="Pre-built chat components: CopilotChat, CopilotPopup, CopilotSidebar, and more."
    href="/reference/components/CopilotChat"
    icon={<LinkIcon />}
  />
</Cards>
