Treated "not in the places it searched" as "doesn't exist"

Any kind of task

Situation: Asking an AI whether anyone has already done a certain kind of project. The person asking already knew of one example.
What the AI did: It searched only official and government sources and wrote that no examples were found. The example the person knew could never have turned up with that search.
How to ask next time (the operator's example): "Before you say there are none, here is one example I know: [example]. First check that your search finds it. If it doesn't, search again with other words or other kinds of sources."
One question to ask: Would this search find the one example already known to exist?
Check it yourself: Ask the AI to list the exact queries and sites it used. Paste one into a search engine yourself and see whether your known example shows up; if it doesn't, "none found" tells you nothing.
AI used (month): Claude Code (2026-09)
Times this mistake was recorded: 5 times
Source: The operator's work records, and videos by Yuru Computer Science Radio (a Japanese YouTube channel)