CopilotKit

Slots (Subcomponents)

Customize any part of the chat UI by overriding individual sub-components via slots.


/** * LangGraph TypeScript agent — CopilotKit showcase integration * * Defines a graph with a chat node and all showcase tools, * wired to CopilotKit via the sdk-js LangGraph adapter so frontend actions * and shared state flow seamlessly. */import { z } from "zod";import { RunnableConfig } from "@langchain/core/runnables";import { tool } from "@langchain/core/tools";import { ToolNode } from "@langchain/langgraph/prebuilt";import { AIMessage, SystemMessage } from "@langchain/core/messages";import {  MemorySaver,  START,  StateGraph,  Annotation,} from "@langchain/langgraph";import { ChatOpenAI } from "@langchain/openai";import {  convertActionsToDynamicStructuredTools,  CopilotKitStateAnnotation,} from "@copilotkit/sdk-js/langgraph";import {  getWeatherImpl,  queryDataImpl,  manageSalesTodosImpl,  getSalesTodosImpl,  scheduleMeetingImpl,  searchFlightsImpl,  generateA2uiImpl,  buildA2uiOperationsFromToolCall,} from "../../shared-tools";// ---------------------------------------------------------------------------// 1. Agent state — extends CopilotKit state with a proverbs list// ---------------------------------------------------------------------------const AgentStateAnnotation = Annotation.Root({  ...CopilotKitStateAnnotation.spec,  proverbs: Annotation<string[]>,});export type AgentState = typeof AgentStateAnnotation.State;// ---------------------------------------------------------------------------// 2. Tools — shared implementations wrapped for LangChain// ---------------------------------------------------------------------------const getWeather = tool(  async ({ location }) => JSON.stringify(getWeatherImpl(location)),  {    name: "get_weather",    description: "Get current weather for a location",    schema: z.object({      location: z.string().describe("City name"),    }),  },);const queryData = tool(  async ({ query }) => JSON.stringify(queryDataImpl(query)),  {    name: "query_data",    description: "Query financial database for chart data",    schema: z.object({      query: z.string().describe("Natural language query"),    }),  },);const manageSalesTodos = tool(  async ({ todos }) => JSON.stringify(manageSalesTodosImpl(todos)),  {    name: "manage_sales_todos",    description: "Create or update the sales todo list",    schema: z.object({      todos: z        .array(          z.object({            id: z.string().optional(),            title: z.string(),            stage: z.string().optional(),            value: z.number().optional(),            dueDate: z.string().optional(),            assignee: z.string().optional(),            completed: z.boolean().optional(),          }),        )        .describe("Array of sales todo items"),    }),  },);const getSalesTodos = tool(  async ({ currentTodos }) => JSON.stringify(getSalesTodosImpl(currentTodos)),  {    name: "get_sales_todos",    description: "Get the current sales todo list",    schema: z.object({      currentTodos: z        .array(          z.object({            id: z.string().optional(),            title: z.string().optional(),            stage: z.string().optional(),            value: z.number().optional(),            dueDate: z.string().optional(),            assignee: z.string().optional(),            completed: z.boolean().optional(),          }),        )        .optional()        .nullable()        .describe("Current todos if any"),    }),  },);const scheduleMeeting = tool(  async ({ reason, durationMinutes }) =>    JSON.stringify(scheduleMeetingImpl(reason, durationMinutes)),  {    name: "schedule_meeting",    description: "Schedule a meeting (requires user approval via HITL)",    schema: z.object({      reason: z.string().describe("Reason for the meeting"),      durationMinutes: z.number().optional().describe("Duration in minutes"),    }),  },);const searchFlights = tool(  async ({ flights }) => JSON.stringify(searchFlightsImpl(flights)),  {    name: "search_flights",    description: "Search for available flights",    schema: z.object({      flights: z        .array(          z.object({            airline: z.string(),            airlineLogo: z.string().optional(),            flightNumber: z.string(),            origin: z.string(),            destination: z.string(),            date: z.string(),            departureTime: z.string(),            arrivalTime: z.string(),            duration: z.string(),            status: z.string(),            statusColor: z.string().optional(),            price: z.string(),            currency: z.string().optional(),          }),        )        .describe("Array of flight results"),    }),  },);const generateA2ui = tool(  async ({ messages, contextEntries }) => {    const prep = generateA2uiImpl({ messages, contextEntries });    const secondaryModel = new ChatOpenAI({ temperature: 0, model: "gpt-4.1" });    const renderTool = tool(async () => "rendered", {      name: "render_a2ui",      description: "Render a dynamic A2UI v0.9 surface.",      schema: z.object({        surfaceId: z.string().describe("Unique surface identifier."),        catalogId: z.string().describe("The catalog ID."),        components: z          .array(z.record(z.unknown()))          .describe("A2UI v0.9 component array."),        data: z          .record(z.unknown())          .optional()          .describe("Optional initial data model."),      }),    });    const modelWithTool = secondaryModel.bindTools!([renderTool], {      tool_choice: { type: "function", function: { name: "render_a2ui" } },    });    const response = await modelWithTool.invoke([      new SystemMessage({ content: prep.systemPrompt }),      ...prep.messages.map((m) => m as any),    ]);    const aiMsg = response as AIMessage;    if (!aiMsg.tool_calls?.length) {      return JSON.stringify({ error: "LLM did not call render_a2ui" });    }    const args = aiMsg.tool_calls[0].args as Record<string, unknown>;    return JSON.stringify(buildA2uiOperationsFromToolCall(args));  },  {    name: "generate_a2ui",    description: "Generate dynamic A2UI surface components",    schema: z.object({      messages: z.array(z.record(z.unknown())).describe("Chat messages"),      contextEntries: z        .array(z.record(z.unknown()))        .optional()        .describe("Context entries"),    }),  },);const tools = [  getWeather,  queryData,  manageSalesTodos,  getSalesTodos,  scheduleMeeting,  searchFlights,  generateA2ui,];// ---------------------------------------------------------------------------// 3. Chat node — binds backend + frontend tools, invokes the model// ---------------------------------------------------------------------------async function chatNode(state: AgentState, config: RunnableConfig) {  const model = new ChatOpenAI({ temperature: 0, model: "gpt-4o" });  const modelWithTools = model.bindTools!([    ...convertActionsToDynamicStructuredTools(state.copilotkit?.actions ?? []),    ...tools,  ]);  const systemMessage = new SystemMessage({    content: `You are a helpful assistant. The current proverbs are ${JSON.stringify(state.proverbs)}.`,  });  const response = await modelWithTools.invoke(    [systemMessage, ...state.messages],    config,  );  return { messages: response };}// ---------------------------------------------------------------------------// 4. Routing — send tool calls to tool_node unless they're CopilotKit actions// ---------------------------------------------------------------------------function shouldContinue({ messages, copilotkit }: AgentState) {  const lastMessage = messages[messages.length - 1] as AIMessage;  if (lastMessage.tool_calls?.length) {    const actions = copilotkit?.actions;    const toolCallName = lastMessage.tool_calls![0].name;    if (!actions || actions.every((action) => action.name !== toolCallName)) {      return "tool_node";    }  }  return "__end__";}// ---------------------------------------------------------------------------// 5. Compile the graph// ---------------------------------------------------------------------------const workflow = new StateGraph(AgentStateAnnotation)  .addNode("chat_node", chatNode)  .addNode("tool_node", new ToolNode(tools))  .addEdge(START, "chat_node")  .addEdge("tool_node", "chat_node")  .addConditionalEdges("chat_node", shouldContinue as any);const memory = new MemorySaver();export const graph = workflow.compile({  checkpointer: memory,});

What is this?#

Every CopilotKit chat component is built from composable slots, named sub-components you can override individually. The slot system gives you three levels of customization without needing to rebuild the entire UI:

  1. Tailwind classes — pass a string to add/override CSS classes
  2. Props override — pass an object to override specific props on the default component
  3. Custom component — pass your own React component to fully replace a slot

Slots are recursive: you can drill into nested sub-components at any depth.

What it looks like in code#

The chat-slots cell above overrides three slots on a single <CopilotChat> — the welcome screen, the assistant message card, and the input's disclaimer. Each slot is just a prop; the demo extracts them into locals so the override points are easy to see.

Welcome screen slot#

The welcomeScreen prop replaces the empty-state view shown before the first message is sent. The demo swaps in a gradient card that still renders the default input and suggestions:

slot-overrides.snippet.tsx
import type {  CopilotChatAssistantMessage,  CopilotChatInput,  CopilotChatView,} from "@copilotkit/react-core/v2";declare const CustomWelcomeScreen: React.ComponentType;declare const CustomAssistantMessage: React.ComponentType;declare const CustomDisclaimer: React.ComponentType;export function ChatSlotsTeachingExtracts() {  const welcomeScreen =    CustomWelcomeScreen as unknown as typeof CopilotChatView.WelcomeScreen;

Assistant message slot#

Drill into messageView={{ assistantMessage: ... }} to wrap every assistant response. The cell wraps the default component with a tinted card and a small "slot" badge so you can see the override is active during the message flow:

slot-overrides.snippet.tsx
import type {  CopilotChatAssistantMessage,  CopilotChatInput,  CopilotChatView,} from "@copilotkit/react-core/v2";declare const CustomWelcomeScreen: React.ComponentType;declare const CustomAssistantMessage: React.ComponentType;declare const CustomDisclaimer: React.ComponentType;export function ChatSlotsTeachingExtracts() {  const welcomeScreen =    CustomWelcomeScreen as unknown as typeof CopilotChatView.WelcomeScreen;  const messageView = {    assistantMessage:      CustomAssistantMessage as unknown as typeof CopilotChatAssistantMessage,  };

Disclaimer slot#

The input={{ disclaimer: ... }} sub-slot lets you replace the small text shown below the input. The demo uses it to display a visibly tagged disclaimer so reviewers can tell the override is still in effect once the welcome screen is gone:

slot-overrides.snippet.tsx
import type {  CopilotChatAssistantMessage,  CopilotChatInput,  CopilotChatView,} from "@copilotkit/react-core/v2";declare const CustomWelcomeScreen: React.ComponentType;declare const CustomAssistantMessage: React.ComponentType;declare const CustomDisclaimer: React.ComponentType;export function ChatSlotsTeachingExtracts() {  const welcomeScreen =    CustomWelcomeScreen as unknown as typeof CopilotChatView.WelcomeScreen;  const messageView = {    assistantMessage:      CustomAssistantMessage as unknown as typeof CopilotChatAssistantMessage,  };  const input = {    disclaimer:      CustomDisclaimer as unknown as typeof CopilotChatInput.Disclaimer,  };

Tailwind Classes#

The simplest way to customize a slot. Pass a Tailwind class string and it will be merged with the default component's classes.

page.tsx
import { CopilotChat } from "@copilotkit/react-core/v2";

export function Chat() {
  return (
    <CopilotChat
      messageView="bg-gray-50 dark:bg-gray-900 p-4"
      input="border-2 border-blue-400 rounded-xl"
    />
  );
}

Props Override#

Pass an object to override specific props on the default component. This is useful for adding className, event handlers, data attributes, or any other prop the default component accepts.

page.tsx
<CopilotChat
  messageView={{
    className: "my-custom-messages",
    "data-testid": "message-view",
  }}
  input={{ autoFocus: true }}
/>

Custom Components#

For full control, pass your own React component. It receives all the same props as the default component.

page.tsx
import { CopilotChat } from "@copilotkit/react-core/v2";

const CustomMessageView = ({ messages, isRunning }) => (
  <div className="space-y-4 p-6">
    {messages?.map((msg) => (
      <div key={msg.id} className={msg.role === "user" ? "text-right" : "text-left"}>
        {msg.content}
      </div>
    ))}
    {isRunning && <div className="animate-pulse">Thinking...</div>}
  </div>
);

export function Chat() {
  return <CopilotChat messageView={CustomMessageView} />;
}

Nested Slots (Drill-Down)#

Slots are recursive. You can customize sub-components at any depth by nesting objects.

Two levels deep#

Override the assistant message's toolbar within the message view:

page.tsx
<CopilotChat
  messageView={{
    assistantMessage: {
      toolbar: CustomToolbar,
      copyButton: CustomCopyButton,
    },
    userMessage: CustomUserMessage,
  }}
/>

Three levels deep#

Override a specific button inside the assistant message toolbar:

page.tsx
<CopilotChat
  messageView={{
    assistantMessage: {
      copyButton: ({ onClick }) => (
        <button onClick={onClick}>Copy</button>
      ),
    },
  }}
/>

Labels#

Customize any text string in the UI via the labels prop. This is a separate convenience prop on CopilotChat, CopilotSidebar, and CopilotPopup, not part of the slot system.

page.tsx
<CopilotChat
  labels={{
    chatInputPlaceholder: "Ask your agent anything...",
    welcomeMessageText: "How can I help you today?",
    chatDisclaimerText: "AI responses may be inaccurate.",
  }}
/>

Available Slots#

CopilotChat / CopilotSidebar / CopilotPopup#

These are the root-level slot props available on all chat components:

SlotDescription
messageViewThe message list container.
scrollViewThe scroll container with auto-scroll behavior.
inputThe text input area with send/transcribe controls.
suggestionViewThe suggestion pills shown below messages.
welcomeScreenThe initial empty-state screen (pass false to disable).

CopilotSidebar and CopilotPopup also have:

SlotDescription
headerThe modal header bar.
toggleButtonThe open/close toggle button.