Display components

"""PydanticAI agent backing the Tool-Based Generative UI demo.Mirrors showcase/integrations/langgraph-python/src/agents/gen_ui_tool_based.py.The frontend registers `render_bar_chart` and `render_pie_chart` tools via`useComponent`. CopilotKit's runtime injects those tool definitions into theagent request at runtime, so the agent does not need to declare them locally —PydanticAI's AG-UI bridge surfaces frontend-registered tools to the model oneach run, and the model decides when to call them."""from __future__ import annotationsfrom textwrap import dedentfrom pydantic_ai import Agentfrom pydantic_ai.models.openai import OpenAIResponsesModelSYSTEM_PROMPT = dedent(    """    You are a data visualization assistant.    When the user asks for a chart, call `render_bar_chart` or    `render_pie_chart` with a concise title, short description, and a    `data` array of `{label, value}` items. Pick bar for comparisons over    a small set of categories; pick pie for composition / share-of-whole.    Keep chat responses brief — let the chart do the talking.    """).strip()agent = Agent(    model=OpenAIResponsesModel("gpt-4.1-mini"),    system_prompt=SYSTEM_PROMPT,)

What is this?#

Render-only generative UI lets you register React components as tools your agent can invoke. When the agent calls the tool, CopilotKit renders your component directly in the chat with the tool's arguments as props; no handler logic or user interaction required.


useComponent({
name: "showChart",
description: "Populate data and show the user a chart",
parameters: ChartProps,
render: Chart
});


export const ChartProps = z.object({
  title: z.string(),
  data: z.array(z.object({ label: z.string(), value: z.number() })),
});

export function Chart({ title, data }: z.infer<typeof ChartProps>) {
  return (
    <div>
      <h3>{title}</h3>
      <ResponsiveContainer width="100%" height={300}>
        <BarChart data={data}>
          <XAxis dataKey="label" /><YAxis /><Tooltip />
          <Bar dataKey="value" fill="#6366f1" />
        </BarChart>
      </ResponsiveContainer>
    </div>
  );
}

When should I use this?#

Use render-only generative UI when you want to:

Display rich UI (cards, charts, tables) inline in the chat
Show structured data from agent responses
Render previews, status indicators, or visual feedback
Let the agent present information beyond plain text

How it works in code#

The renderer component receives the tool's arguments as typed props and mounts inline in the chat. Below is the chart renderer wired up in the canonical demo — the agent emits the data, the component draws it.

bar-chart-renderer.snippet.tsx

import { useComponent } from "@copilotkit/react-core/v2";import { z } from "zod";// Stand-ins for the locally-authored bar chart component + its prop// schema. In a real page, these live in the demo directory (e.g.// `./bar-chart.tsx` exporting `BarChart` and `barChartPropsSchema`).declare const BarChart: React.ComponentType<{  title: string;  data: { label: string; value: number }[];}>;declare const barChartPropsSchema: z.ZodSchema;export function BarChartRenderer() {  useComponent({    name: "render_bar_chart",    description: "Display a bar chart with labeled numeric values.",    parameters: barChartPropsSchema,    render: BarChart,  });