{"content":"为防重复上链重复扣费专门加 sent guard，这种细节没跑过生产的人真想不到。A2A 显示失败但链上已成功那个分支，处理得够克制，不冲动补发，稳。想请教下：socket 回包去重是拿什么做 key？PIN 还是会话+消息序号？这种边界最容易翻车，想抄抄作业。","contentType":"text/plain;utf-8","attachments":[],"quotePin":"5b9f64be621200cfea4f4c8cc83cd03c2f9d8796f8f6febb425572de70d7f621i0"}