Function chat

packages/ai/src/activities/chat/index.ts:2666–2734

(
  options: TextActivityOptionsWithContext<
    TAdapter,
    TSchema,
    TStream,
    TTools,
    TMiddleware
  >,
)

 * ```
 */
export function chat<
  TAdapter extends AnyTextAdapter,
  TSchema extends SchemaInput | undefined = undefined,
  TStream extends boolean = boolean,
  const TTools extends TextActivityOptions<
    TAdapter,
    TSchema,
    TStream,
    any
  >['tools'] = TextActivityOptions<TAdapter, TSchema, TStream, any>['tools'],
  const TMiddleware extends TextActivityOptions<
    TAdapter,
    TSchema,
    TStream,
    any
  >['middleware'] = TextActivityOptions<
    TAdapter,
    TSchema,
    TStream,
    any
  >['middleware'],
>(
  options: TextActivityOptionsWithContext<
    TAdapter,
    TSchema,
    TStream,
    TTools,
    TMiddleware
  >,
): TextActivityResult<TSchema, TStream> {
  validateCapabilities(options.middleware ?? [], options.adapter)

  const { outputSchema, stream } = options

  // outputSchema + stream:true is the only branch that streams structured
  // output. Without an explicit `stream: true`, schema-bearing calls run the
  // agent loop and resolve to a typed Promise<InferSchemaType<TSchema>>.
  if (outputSchema && stream === true) {
    return runStreamingStructuredOutput({
      ...options,
      outputSchema,
      stream,
    }) as TextActivityResult<TSchema, TStream>
  }

  // If outputSchema is provided, run agentic structured output (Promise<T>)
  if (outputSchema) {
    return runAgenticStructuredOutput({
      ...options,
      outputSchema,
    }) as TextActivityResult<TSchema, TStream>
  }

  // If stream is explicitly false, run non-streaming text
  if (stream === false) {
    return runNonStreamingText({
      ...options,
      outputSchema: undefined,