フリー問題

問題文

A search subagent queries an external index. Sometimes the index times out; sometimes it returns successfully with zero matches. Currently both cases return an empty array. The coordinator cannot decide what to do next. What is the correct fix?

選択肢

1. Have the subagent terminate the entire workflow when the index times out.
2. Always retry empty results once, in case the index was temporarily unavailable.
3. Log the timeout on the subagent side and return an empty array to keep the interface simple.
4. Distinguish access failures from valid empty results in the response, so the coordinator can retry the former and accept the latter.