useSendFollowUpMessage

A user action in your view does not advance the conversation: the model only acts on conversation turns. useSendFollowUpMessage posts a message into the conversation as if the user had typed it, starting the next assistant turn.

Example

Tapping a product asks the model to tell the shopper more about it, while the carousel stays on screen.

import { useSendFollowUpMessage } from "skybridge/web";
import { useToolInfo } from "../helpers.js"; // generated, type-safe from server schema

function Carousel({ products }: { products: Product[] }) {
  const sendFollowUpMessage = useSendFollowUpMessage();

  return (
    <div className="carousel">
      {products.map((product) => (
        // scrollToBottom: false keeps the carousel in view on ChatGPT; ignored elsewhere
        <button
          key={product.id}
          onClick={() =>
            sendFollowUpMessage(`Tell me more about the ${product.name}`, {
              scrollToBottom: false,
            })
          }
        >
          {product.name}
        </button>
      ))}
    </div>
  );
}

Returns

useSendFollowUpMessage returns a single, memoized function, safe to pass to effects and handlers.

`sendFollowUpMessage`

sendFollowUpMessage(
  prompt: string | ContentBlock[],
  options?: { scrollToBottom?: boolean; target?: "active" | "new" }
): Promise<void>;

Posts the message and returns the host’s promise, which rejects when the host refuses the message. The promise carries no value: any model reply lands in the conversation, not back in the view.

prompt the text posted as a user turn, model-visible, as if the user had typed it, or an array of MCP content blocks. The view keeps running after the message is posted.
options
- scrollToBottom asks the host to scroll the conversation to the newest message after posting; omit it for the host default, or set false to keep the scroll position and the view on screen.
- target: "new" sends the message to a new conversation instead of the active one. On hosts that don’t advertise openai/message, the call rejects with a NotSupportedError and nothing is posted.

scrollToBottom is specific to ChatGPT. target and titled items come from the OpenAI MCP extensions: only ChatGPT reads them, and mobile only supports the active conversation. ChatGPT doesn’t accept audio blocks, nor resource links on iOS.

Titled items

On ChatGPT, a text or image block with _meta["openai/title"] becomes a labeled item in the message, which the user can remove as one unit. Untitled text stays ordinary message text.

sendFollowUpMessage([
  { type: "text", text: "Compare these two parts:" },
  {
    type: "text",
    text: "M6 hex bolt, 20mm, stainless",
    _meta: { "openai/title": "Hex bolt" },
  },
]);

Content blocks and target are sent through the MCP Apps ui/message request, also inside ChatGPT, so scrollToBottom doesn’t apply to them.

useCallTool

Call a server tool without a conversation turn

useToolInfo

Read the tool result the view mounted with

DataLLM

Sync on-screen state to the model passively

Server

Auth

Identity Providers

Hooks

Utilities

Types

Low-level

useSendFollowUpMessage

Example

Returns

`sendFollowUpMessage`

Titled items

useCallTool

useToolInfo

DataLLM

​Example

​Returns

​sendFollowUpMessage

​Titled items

useCallTool

useToolInfo

DataLLM

Example

Returns

`sendFollowUpMessage`

Titled items