非常多的问题：unknown tool 、失败时历史内容丢失

[xiangwan1]

1. unknown tool
   mac os 26.4，随便跑一个都报 unknown tool

{
pattern:"**/*",
path:"/Users/xxx/project/testonly"
}

Error: unknown tool ""
2. 对于错误的对话历史，刷新后内容完全丢失，连轨迹也没有了
历史加载失败：history unavailable for session "session-31d6e978-c425-4217-994f-1bcdea15c1d5": SessionPersistenceCorruptionError: stored session "session-31d6e978-c425-4217-994f-1bcdea15c1d5" failed validation: Error: session event at seq 129 message must have tool source（internal）

[Electricitysheep]

unknown tool "" 是流式解析 bug（SSE 空 delta 覆盖工具名，#725/#1405 同族，社区多帖复现），历史加载失败是它的次生问题（会话文件被错误状态污染）。

官方修复前的规避 + 同族清单见 FAQ：https://github.com/Electricitysheep/dsh-handbook/blob/main/docs/faq.md

[guntur-d]

On the "turn keeps failing / runs forever" symptom: after the unknown tool "" error is folded back into history, the model can keep emitting failing calls and the step loop has no bound — the turn issues model request after request until the operator stops it. That is a missing loop-hygiene guarantee rather than a model issue.

Tested fix in our fork (PR #3): the loop tracks consecutive steps whose tool calls ALL error and, past maxConsecutiveToolFailures (default 3, a validated agent-loop config field), ends the turn with a logged, model-visible notice instead of issuing another request. A step that produces text or commits at least one successful tool result resets the counter. Full unit suite passes, including a test that drives a scripted model through 3 all-error steps and asserts the turn ends at the cap.

[guntur-d]

关于「整轮不断失败／无限运行」的症状：在 unknown tool "" 错误被折叠回历史后，模型可能持续发出失败调用，而 step 循环没有任何上限——这一轮会不断发起模型请求，直到操作者手动停止。这是缺失的 loop-hygiene（循环卫生）保证，而不是模型问题。

我们 fork 中的已测试修复（PR #3）：loop 追踪工具调用全部出错的连续步骤，超过 maxConsecutiveToolFailures（默认 3，经过校验的 agent-loop 配置字段）后以一条已记录且模型可见的通知结束本轮，而不是再发起一次请求。产出文本或至少提交一条成功工具结果的步骤会重置计数器。完整单元测试通过，其中包括驱动脚本化模型经历 3 个全部出错步骤并断言本轮在上限处结束的测试。