PerplexityBot and what the source list leaves out
Perplexity shows its sources, which makes it the best diagnostic available to a contractor. It is worth being precise about what that list does and does not tell you.
The crawler
PerplexityBot requests pages on Perplexity's behalf and obeys robots.txt like any other agent. Same two checks as everywhere else: is it permitted, and do your logs show it actually arriving. A site that permits it and never sees it has a discoverability problem rather than a permissions problem.
What the visible sources tell you
Which pages that answer rested on, in that run. That is genuinely useful and it is the fastest route to the finding most contractors have never seen: that the sources speaking for their trade in their town are mostly not contractor websites. Ten questions will show you the pattern.
What they do not tell you
Partial transparency · visible sources, invisible weighting
Three things, and conflating any of them with the visible list is where analysis goes wrong. You do not see what was retrieved and discarded, so absence from the list is not evidence a page was never read. You do not see the weighting, so you cannot tell whether the first source did most of the work or none of it. And you do not see why your competitor was named rather than you, because that judgement is not exposed anywhere.
The list is a record of inputs, and reading it as a ranking is the mistake that turns a good diagnostic into a bad conclusion.
Using it without over-reading it
Treat the recurring domains as a prospect list rather than as a ranking factor. If one review platform appears in most answers about your trade and your profile there is half-complete, that is a concrete afternoon of work with a plausible benefit and no promise attached. The full method is here.