Method createStreamResult

src/node/services/streamManager.ts:1515–1550

(
    request: StreamRequestConfig,
    abortController: AbortController,
    stepTracker?: StepMessageTracker
  )

  }

  private createStreamResult(
    request: StreamRequestConfig,
    abortController: AbortController,
    stepTracker?: StepMessageTracker
  ): Awaited<ReturnType<typeof streamText>> {
    return streamText({
      model: request.model,
      messages: request.messages,
      system: request.system,
      abortSignal: abortController.signal,
      prepareStep: async ({ messages: stepMessages }) => {
        // streamText runs multiple internal LLM calls (steps) when tools are enabled.
        // Strip workflow run records from same-turn tool results (history-level redaction in
        // applyToolOutputRedaction can't see these), then extract supported attachments out of
        // tool-result JSON so providers don't treat them as text.
        const withoutWorkflowRunRecords = stripWorkflowRunRecordsFromModelMessages(stepMessages);
        const rewritten =
          await extractToolMediaAsUserMessagesFromModelMessages(withoutWorkflowRunRecords);
        const effectiveMessages = rewritten === stepMessages ? stepMessages : rewritten;
        if (stepTracker) {
          stepTracker.latestMessages = effectiveMessages;
        }
        request.onStepMessages?.(effectiveMessages);
        if (rewritten === stepMessages) return undefined;
        return { messages: rewritten };
      },
      onChunk: request.onChunk,
      tools: request.tools,
      stopWhen: this.createStopWhenCondition(request),
      // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-assignment
      providerOptions: request.providerOptions as any, // Pass provider-specific options (thinking/reasoning config)
      headers: request.headers, // Per-request HTTP headers (e.g., anthropic-beta for 1M context)
      maxOutputTokens: request.maxOutputTokens,
      ...(request.streamCallSettings ?? {}),
    });
  }

  /**
   * Atomically creates a new stream with all necessary setup