What tools are you thinking of? I think saying it links its sources is absolutely not a stretch. My experience is with Kagi and with Perplexity; both of which it has even returned messages saying something along the lines of the source documents not being able to answer the question.
Copilot doesn't link to the sources. It doesn't really know what their sources are. It links to article that may be related to what it just said. Many times the sources even contradict what was said. So definitely not a source in that case
