Reply

A reply sends a message back into the conversation. Agents can reply with plain text, markdown with files, or interactive cards, depending on provider capabilities.

Interactive cards include buttons, dropdowns, links, and text inputs. When a user interacts with a card, the onAction handler fires with the action ID and selected value.

Use replies when the agent needs to communicate something to the participant in the conversation.

Replies are user-facing messages your agent sends back into the conversation. Use signals when you need to update conversation state, trigger workflows, or resolve the thread without messaging the user.

The public API is ctx.reply(content, options?). You can also return a string or JSX card from a handler instead of calling ctx.reply() directly.

To send a reply from your backend without going through the bridge handler, use the Send an agent reply API.

Channel support

See Channels overview for the full matrix.

Reply types

The following table summarizes the reply types your agent can send:

To change a message after you send it, see Edit sent messages.

Plain text

Send a simple string reply with ctx.reply():

await ctx.reply('Hello! How can I help?');

Markdown

Send formatted text by passing a markdown string to ctx.reply():

await ctx.reply('**Report generated.** See the attached PDF.');

Sending attachments

Include files with string or markdown replies via the optional second argument.

When sending attachments, keep these limits in mind:

• Attachments are limited to 25 MB per file.
• Files are only supported with string or markdown replies, not card replies.
• Provide each file with exactly one of url or data.
• Prefer url for larger files. Inline data is capped at 5 MB per file (and 5 MB aggregate per message).

File reference type

Each file uses a FileRef object with the following shape:

type FileRef = {
  filename: string;
  mimeType?: string;
  data?: string | Uint8Array | ArrayBuffer | Blob;
  url?: string;
};

Use url for larger files. Novu fetches public HTTP(S) URLs server-side. Use data for small generated files in memory.

The following examples show both approaches:

Interactive cards

Cards are structured messages with buttons, dropdowns, links, and more. Build them with function calls or JSX.

The following example builds a card with the function call API:

import {
  Card, Button, CardText, Actions,
  Select, SelectOption, Divider, CardLink,
} from '@novu/framework';

await ctx.reply(Card({ title: 'Order #1234', children: [
  CardText('Your order is ready for pickup.'),
  Divider(),
  Actions([
    Button({ id: 'ack', label: 'Acknowledge' }),
    Button({ id: 'escalate', label: 'Escalate', style: 'danger' }),
  ]),
  CardLink({ url: 'https://example.com/order/1234', children: 'View details' }),
] }));

Add "jsxImportSource": "@novu/framework" to tsconfig.json, then return JSX from a handler or pass it to ctx.reply():

/** @jsxImportSource @novu/framework */
import {
  Actions, agent, Button, Card, CardLink, CardText, Divider,
} from '@novu/framework';

export const myAgent = agent('my-agent', {
  onMessage: async (message, ctx) => {
    return (
      <Card title="Order #1234">
        <CardText>Your order is ready for pickup.</CardText>
        <Divider />
        <Actions>
          <Button id="ack" label="Acknowledge" />
          <Button id="escalate" label="Escalate" style="danger" />
        </Actions>
        <CardLink url="https://example.com/order/1234">View details</CardLink>
      </Card>
    );
  },
});

You can also pass JSX to ctx.reply():

await ctx.reply(
  <Card title="Order #1234">
    <CardText>Your order is ready for pickup.</CardText>
  </Card>,
);

When a user clicks a button or selects a dropdown value, onAction fires with action.id and action.value. See Handlers and context.

Available card components

The following table lists the card components you can use in replies:

Related