A business can be invisible to every AI assistant for two entirely separate reasons, and they are fixed in two different places by two different people. The first is robots.txt, a file on your own site naming the crawlers and telling them to stay out. The second is bot protection at your CDN or firewall, which returns 403 to those same crawlers no matter what robots.txt says.
We know the second one from our own estate rather than from an article. Opening one of our properties to AI crawlers took three changes: disabling a bot-protection rule, turning off a managed robots.txt that a platform had generated, and purging the cached copy of that file. Any one of those left alone kept the crawlers out while the other two read as correct.
Neither gate is visible from inside the business. Every page loads perfectly in your browser, the site ranks normally in Google, and nothing anywhere says that ChatGPT was turned away. The only way to find it is to ask the server as each crawler and compare, which is what the free audit does.
The second half of this work is the opposite problem. Plenty of shops now have an AI answering the phone or sitting on the website, and almost nobody has read a transcript of what it actually tells customers about price, timing or whether a repair is covered. That is a different audit and it is the one with real money attached to being wrong.