# TextMessageStartEvent

# Interface: TextMessageStartEvent

Defined in: [types.ts:811](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L811)

Emitted when a text message starts.

## Extends

- [`BaseAGUIEvent`](BaseAGUIEvent.md)

## Properties

### messageId

```ts
messageId: string;
```

Defined in: [types.ts:814](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L814)

Unique identifier for this message

***

### model?

```ts
optional model: string;
```

Defined in: [types.ts:756](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L756)

Model identifier for multi-model support

#### Inherited from

[`BaseAGUIEvent`](BaseAGUIEvent.md).[`model`](BaseAGUIEvent.md#model)

***

### rawEvent?

```ts
optional rawEvent: unknown;
```

Defined in: [types.ts:758](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L758)

Original provider event for debugging/advanced use cases

#### Inherited from

[`BaseAGUIEvent`](BaseAGUIEvent.md).[`rawEvent`](BaseAGUIEvent.md#rawevent)

***

### role

```ts
role: "user" | "assistant" | "tool" | "system";
```

Defined in: [types.ts:816](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L816)

Role of the message sender

***

### timestamp

```ts
timestamp: number;
```

Defined in: [types.ts:754](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L754)

#### Inherited from

[`BaseAGUIEvent`](BaseAGUIEvent.md).[`timestamp`](BaseAGUIEvent.md#timestamp)

***

### type

```ts
type: "TEXT_MESSAGE_START";
```

Defined in: [types.ts:812](https://github.com/TanStack/ai/blob/main/packages/typescript/ai/src/types.ts#L812)

#### Overrides

[`BaseAGUIEvent`](BaseAGUIEvent.md).[`type`](BaseAGUIEvent.md#type)