UIMessage

Defined in: packages/ai/src/types.ts:785

UIMessage - Domain-specific message format optimized for building chat UIs Contains parts that can be text, tool calls, or tool results. Generic over the structured-output data type so useChat({ outputSchema })'s schema narrows parts.find(p => p.type === 'structured-output').data on the consumer side without manual casts.

Type Parameters

TData

TData = unknown

Properties

createdAt?

optional createdAt?: Date;

Defined in: packages/ai/src/types.ts:789

id

id: string;

Defined in: packages/ai/src/types.ts:786

metadata?

optional metadata?: Record<string, any>;

Defined in: packages/ai/src/types.ts:796

Optional AG-UI metadata bag. TanStack writes the tanstack key. User keys stay at the top.

name?

optional name?: string;

Defined in: packages/ai/src/types.ts:791

Optional AG-UI sender name. Converters preserve it across wire and persist.

parts

parts: MessagePart<TData>[];

Defined in: packages/ai/src/types.ts:788

role

role: "assistant" | "user" | "activity" | "system";

Defined in: packages/ai/src/types.ts:787