设计 Agent 的工具和循环结构

只是写法示意，不是完整程序。

// ANS 零依赖 ReAct 智能体防死循环主控回路 (ans-agent-loop.ts)
export async function runAnsAgentLoop(goal: string, maxSteps = 8, stepFn: (s: number) => Promise<{ done: boolean; output: string }>) {
  for (let step = 1; step <= maxSteps; step++) {
    const res = await stepFn(step);
    if (res.done) return { status: "COMPLETED", steps: step, output: res.output };
  }
  return { status: "MAX_STEPS_ABORTED", steps: maxSteps, output: "已触发安全步数熔断" };
}