Function buildRunStream

packages/ai-sandbox-cloudflare/src/chat-coordinator.ts:118–140

* Run `chat()` IN the DO, streaming its `StreamChunk`s. `stream: true` (with no * outputSchema) makes chat() return an `AsyncIterable ` directly — * no cast needed for the run driver. Both middlewares run `setup` before * streaming begins: our middleware provides the DO-backed b

(
    input: StartRunInput,
  )

   * and `withSandbox` provides the sandbox handle the harness adapter needs.
   */
  protected override buildRunStream(
    input: StartRunInput,
  ): AsyncIterable<StreamChunk> {
    const { adapter, sandbox, tools, systemPrompts } = this.config(input)
    const sessionId = input.metadata?.sessionId
    const modelOptions =
      typeof sessionId === 'string' && sessionId !== ''
        ? { sessionId }
        : undefined
    return chat({
      threadId: input.threadId,
      adapter,
      messages: input.messages,
      stream: true,
      ...(tools !== undefined ? { tools } : {}),
      ...(systemPrompts !== undefined ? { systemPrompts } : {}),
      ...(modelOptions !== undefined ? { modelOptions } : {}),
      middleware: [
        this.bridgeProvisionerMiddleware(input),
        withSandbox(sandbox),
      ],
    })
  }

  /** Drop the per-run bridge once the run is terminal (override from base). */
  protected override onRunSettled(runId: string): void {