> ## Documentation Index
> Fetch the complete documentation index at: https://docs.r28.ai/charter/llms.txt
> Use this file to discover all available pages before exploring further.

# Objects

> Every object and enum the Chat tools accept.

## Model tree

<div className="model-tree"><div className="model-tree-scroll"><div className="tree-node"><a href="#messagemetadata">MessageMetadata</a></div></div></div>

## MessageMetadata

Application-specific metadata attached to a message.

<div className="reference-table">
  | Field                                                                | Type     | Description                                           |
  | -------------------------------------------------------------------- | -------- | ----------------------------------------------------- |
  | `eventType` <span className="required" title="required">\*</span>    | `string` | The name of the metadata event, e.g. 'task\_created'. |
  | `eventPayload` <span className="required" title="required">\*</span> | `object` | A JSON object of the data associated with the event.  |
</div>