What is required and what is optional?
| Item | Required for AI features? | Our view |
|---|---|---|
| Indexable, crawlable pages | Yes, for Google's AI features | The foundation. Check it first. |
| Schema markup | No | Worth adding when it matches visible text. |
| llms.txt | No | Cheap to keep accurate. Effect unproven. |
| Crawler rules in robots.txt | Only if you want to limit access | Set deliberately, per crawler. |
When is schema markup worth it?
When every fact in the markup also appears in the visible text. Useful types include Organization, Service, Article, BreadcrumbList and FAQPage. Google has limited where FAQ rich results appear, so treat FAQ markup as a clarity aid, not a display feature. Markup that describes something the page does not show is worse than none.
What is llms.txt?
A plain Markdown file at the root of a site that lists and describes its most useful pages. Google states it does not need such files, and no source we found shows that it changes citations. If you add one, keep it short and accurate.
What about robots.txt?
Decide on purpose which crawlers may read your site. Some crawlers fetch pages to answer a user's question, others to collect training data. They are separate decisions.
Related answers
Assistants change often. Where a point is inference rather than a published rule, the page says so. Results vary and are never guaranteed.