> ## Documentation Index
> Fetch the complete documentation index at: https://docs.novu.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Emit custom events

> Send a named payload from a custom code agent handler with ctx.emit. Agent Chat renders it as a data part.

`ctx.emit({ name, data })` sends a named payload on the current turn. It is not a chat message. It is not a [signal](/agents/custom-code-agent/building-blocks/signals).

Use `ctx.reply()` when the subscriber must see text or a card. Use `ctx.emit()` when your client needs structured data during the turn, for example progress or a machine-readable status.

The call posts at once. It does not wait for `ctx.reply()`. If the bridge has no `eventsUrl`, the call is a no-op.

## Channel support

| Channel                                   | What the subscriber sees                                          |
| ----------------------------------------- | ----------------------------------------------------------------- |
| [Agent Chat](/agents/channels/agent-chat) | A `data` part on the in-flight assistant message                  |
| Slack, Teams, WhatsApp, Telegram, Email   | Nothing in the thread. Novu stores the event on the conversation. |

## Send an event

`name` is a non-empty string. `data` is yours. JSON size must stay at or under 64 KB. Novu drops the event when `name` is empty or `data` is over the limit.

```ts theme={null}
onMessage: async (message, ctx) => {
  await ctx.emit({
    name: 'order-progress',
    data: { pct: 70 },
  });

  await ctx.reply('Updating your order…');
},
```

You can call `ctx.emit` more than once in one turn. Each call is a separate event.

## Agent Chat

Agent Chat adds each event to the assistant message as `part.type === 'data'`. The fields are `name` and `data`.

Render the parts you support. Skip the rest. The part stays on the message.

Client walk: [Custom data parts](/agents/channels/agent-chat/chat-ui#custom-data-parts).

## Related

<Columns cols={2}>
  <Card icon="message-circle" href="/agents/custom-code-agent/building-blocks/reply" title="Reply">
    Send text, markdown, files, or cards to the subscriber.
  </Card>

  <Card icon="signal" href="/agents/custom-code-agent/building-blocks/signals" title="Signals">
    Metadata, workflow triggers, and conversation resolution.
  </Card>

  <Card icon="list" href="/agents/channels/agent-chat/chat-ui#custom-data-parts" title="Agent Chat data parts">
    Render `part.type === 'data'` in your product UI.
  </Card>
</Columns>