I added llms.txt so you don't have to
I shipped an llms.txt on this blog last week, then went looking for proof anything reads it. Google's John Mueller compares it to the old keywords meta tag; a 2026 study of ~38,000 AI-cited domains found zero citation advantage (p=0.85). Where it's genuinely useful, how to test it against your own logs, and why a helper file is a long shot on a web that already ignores robots.txt.