Generally no for public marketing and educational content, since being crawled is a prerequisite for being cited by AI answer engines — the more relevant question is usually which specific crawlers to allow and what content, if any, is genuinely sensitive enough to exclude.
Being cited by an AI answer engine requires the crawler to have accessed and understood your content first. Blocking AI crawlers on public content that exists specifically to be found and understood removes any chance of being the cited source, in favour of a competitor who did not block them.
Genuinely restricted content — behind HCP verification, or internal — should already be inaccessible to any crawler through proper access control, not through a robots.txt request that a crawler may or may not respect. Robots.txt is a request, not a security mechanism.
Before deciding, check what is currently being cited about you — see AI search visibility audit — since the decision is better informed by evidence of current representation than by a policy decided in the abstract.
It may reduce that specific use for crawlers that respect the block, which is a separate consideration from search and answer-engine visibility and worth weighing against that trade-off explicitly. Blocking does not affect crawlers that ignore robots.txt, so the protection it offers is partial at best.
No, it is a request that well-behaved crawlers respect voluntarily, not an access control mechanism enforced by anything technical. Truly restricted content needs authentication or another real barrier, since a robots.txt entry does not manage to stop a crawler that simply chooses to ignore it.
See how do you get cited by ChatGPT for what makes content more likely to be found, understood, and correctly referenced by AI answer engines directly, which requires being crawled in the very first place rather than excluded from it entirely by a blanket policy.
Content already behind HCP verification or otherwise restricted should be inaccessible to any crawler through proper access control rather than a robots.txt request. For public marketing and educational content built specifically to be found, exclusion mostly removes any chance of being the cited source.
Tell us your concern and we will check what is currently happening before recommending a policy.